STATE UNIVERSITY LIBRARIES S02065728 U This book is due on the date indicated unless recalled by the Libraries. Books not returned on time are subject to replacement charges. Borrowers may access their library accounts at: http://www.lib.ncsu.edu/ads/borrow.html MANUAL OP CATTLE-FEEDING A TREATISE ON THE LAWS OF ANIMAL NUTRITION AND THE CHEMISTRY OF FEEDING-STUFFS IN THEIR APPLICATION TO THE FEEDING OF FARM-ANIMALS. With Illustrations and an Appendix of Useful Tables. By henry p. ARMSBY, Ph.D., DIBBCTOR or THB PENNSYLVANIA STATE COLLEGE AQBICULTUBAIi EXPERIMENT STATION. FIFTH EDITION. THIRD THOUSAND. NEW YORK JOHN WILEY & SONS LONDON CHAPMAN & HALL, Ltd. 1903 Copyright, JOHN WILEY & SONS. PRESS OF BRAUNWORTH & CO, BOOKBINDERS AND PRINTERS BROOKLYN, N. Y. PEEFAOE Investigatioi^ into the laws wliicli form the basis of the ra- tional feeding of Hve-stock has been most actively and indus- triously carried on of late years, and very important advances have been made, especially in Germany, where this branch of apphed science has been most attentively and persistently studied. The period smce the year 1860, in particular, has been a remarkably fruitful one ; within this period the theory of feeding has been placed on a firm, scientific foundation, and the direction of its futui-e progress has been marked out ; and while very much still remains to be done, the results ah-eady achieved are of great practical importance. Unfortunately, however, these results are largely inaccessible to the majority of American feeders, and those of them which appear from time to time in agricultural papers and other pubhcations are deprived of much of their good effect by their necessarily fragmentary character. It is the object of this work to present these results in a connected aad systematic form to American farmers and others interested in stock-feeding, an attempt which, so far as the writer is aware, has not before been made, and a few words as to the scope and aims of such a book wiU therefore be in IV PREFACE. In the writer's view, the highest usefiihiess of a work like the joresent does not consist simply in giving receipts which shall enable the farmer to feed his stock more economically, or to pro- duce more milk or more or better beef, but in so elucidating our knowledge of the unchanging natui'al laws, chemical and physiological, of the nutrition of animals, that the attentive stu- dent shall be able to adapt his practice to the varying conditions in which he may be placed, and, more important still, shall be able to appropriate inteUigently the results of new investiga- tions and follow or take part in the advances of the science. Guided by this idea, the author has not been content simply to state results, but has endeavored, so far as was possible in an elementary work, to indicate the processes by which these results have been reached and the degree of certainty which attaches to them, as well as to point out the directions in which Gur knowledge is still deficient. Only in this way can a cor- rect idea of the present state of the science be obtained or the learner be prepared to appreciate and utilize further progress. Iq this the chiefly practical importance of the subject has not been forgotten. The ultimate object of this branch of appHed science is, of course, to enable us to feed better and more economically ; but the only sure and lasting foundation for a rational practice is a knowledge of the natural laws on which it is based, and with which it must be in accordance in order to be successful. This method of treating the subject naturally makes demands for study and thought on the part of the reader ; the results of twenty years of arduous scientific work by scores of investi- gators are not to be grasped and a^Dpropriated without labor. At the same time the author has endeavored to reduce this PREFACE. V labor as much as is possible without the sacrifice of accuracy and a reasonable degi'ee of fulness. Above all, he has sought to make his work a rehable exponent of the present state of knowledge on the subject of cattle-feeding, and to draw a sharp hue between proved and useful facts, and merely probable hypotheses or speculations. This book was begun as a translation of Wolff's " Land- imrthschaftliche F litter ungslehre" a volume of some two hun- di-ed pages. It was soon found, however, that considerable additions and changes were required to suit it to Ameri- can readers, and the work has finally assumed its present form. Some portions of it are still fi*ee translations of Wolff, but much more of it has been either added or entirely re- written, and a number of illustrations have been introduced, so that the chai'acter of the book has been considerably altered. One of the most marked changes is the substitution, in the Appendix, of Kiihn's tables of the composition and digestibiUty of feeding-stuffs for those of Wolff*. Although the writer does not accept all of Kiihn's opinions, he yet beheves that tables arranged on the plan adopted by Kiihn ai-e, on the whole, preferable to those containing simply aver- ages ; and in view of the changes and additions made else- where in the volume, he has felt justified in making the sub- stitution named, though aware 'that Kiihn's views, on some points, are warmly opposed by Wolff. In addition to the " Fiitterungslehi^e," the author is espe- cially indebted to Wolft"s larger book, "Die Erndhrung der landioir'thschaftlichen Nutzthiere" while other works and the current literature of the subject have been freely consulted. Sept. 1. 1880. TABLE OF CONTENTS. PAQB Introduction 1 PART I, THE GENERAL LAWS OF ANIMAL NUTRITION. CHAPTER I.— The Composition of the Animal Body . . 5 § 1. Proportions of the various tissues .... 5 § 3. Non-nitrogenous matters . . . . . . 7 § 3. Nitrogenous matters ...... 14 § 4. Inorganic or non -volatile matters .... 20 CHAPTER II.— Components of Fodders— Nutrients . . 25 § 1. Definitions 25 § 2. Nitrogenous nutrients 26 § 3. Non-nitrogenous nutrients 38 § 4. Inorganic nutrients ..... . . 47 § 5. Fodder Analysis 48 CHAPTER III.— Digestion and Resorption .... 54 § 1. Digestion 54 § 2. Resorption 66 CHAPTER IV.— Circulation, Respiration, and Excretion. 74 § 1. Circulation 74 §2. Respiration 80 § 3. Excretion 93 Vlll CONTENTS. CHAPTER V. — Methods of Investigation . 55 1. Determination of digestibility § 2. Determination of nutritive effect of a ration CHAPTER VI. — Formation op Flesh .... § 1. Introductory § 2. Organized and circulatory protein . § 3. Feeding with protein alone .... § 4. Feeding with fat or carbhydrates alone . § 5. Feeding with protein and fab .... ^ 6. Feeding with protein and carbhydrates . § 7. Nutritive value of amides § 8. Influence of quantity of food . . . . , CHAPTER VIL— The Formation of Fat § 1. Sources of fat ...... § 2. Feeding with fat alone ..... § 3. Feeding with protein alone .... § 4. Feeding with protein and fat .... § 5. Feeding with protein and carbhydrates . § 6. Influence of other conditions on the production fat CHAPTER VIII.— The Production op Work § 1. Effects of muscular exertion on excretion § 2. The source of muscular power § 3. Internal work ..... of PAGE 104 104 109 119 119 123 128 136 137 143 158 167 169 187 188 189 191 198 202 204 213 PART 11. THE FEEDING-STUFFS. CHAPTER I.— Digestibility § 1. Digestibility of the nutrients of coarse fodder . § 2. Circumstances affecting the digestibility of coarse fodder § 3. Digestibility of the concentrated fodders and their influence on that of coarse fodder .... CHAPTER 11— The Coarse Fodders g 1. Meadow hay, roweu, and pasture 243 245 259 273 288 288 CONTENTS. IX PAGE § 2. The legumes 301 Clover and clover hay 302 Lucerne 307 Vetches 309 Lupines . . . . . . . .310 Other legumes 311 § 3. Hungarian grass 314 § 4. Maize fodder and stover 315 § 5. Tops of root crops 321 § 6. Straw of the cereals 322 §7. Straw of the legumes 326 § 8. Chaff, pods, and maize cob . . . . . 327 CHAPTER III.— Concentrated Fodders . . . .330 § 1. The grains 330 § 2. Bye-products of the grains 337 § 3. The legumes 342 § 4. Oil seeds and oil cake 345 § 5. Animal products ....... 349 § 6. Tubers and roots 355 FABT III. THE FEEDING OF FARM ANIMALS. CHAPTER I.— Feeding Standards CHAPTER II. — Feeding for Maintenance § 1. Oxen §2. Sheep CHAPTER III.— Fattening § 1. Cattle . §2. Sheep . § 3. Swine. CHAPTER IV.— Feeding Working Animals § 1. Introductory .... § 2. Working oxen .... §3. Horses 3G5 374 374 383 392 392 399 404 407 407 408 409 X CONTENTS. PAGE CHAPTER v.— Production of Milk 414 § 1. The milk-glands and their functions , . . 414 § 2. The quantity of milk 419 § 3. The quality of the milk 426 § 4. The feeding standard 431 CHAPTER VI.— Feeding Growing Animals ... 436 § 1. General laws of the nutrition of young animals . . 436 §2. Calves 442 § 3, Lambs 448 §4. Pigs . . . . • 458 § 5. Inorganic nutrients 462 CHAPTER VII.— The Calculation OF Rations ... 466 APPENDIX, Table I. — The composition of feeding-stuffs .... 478 Table II.— The digestibility of feeding-stuffs ... 487 Table III. — Feeding standards for farm animals . . . 493 Table IV. — Proportions of the various parts of cattle, sheep, and hogs 494 MANUAL OP CATTLE-FEEDING. INTEODUCTION. The two objects of agriculture are the production of plants and of animals. We must seek for the laws governing the former in the chemistry and physics of the air, the soil, and manures, and in the phenomena of vegetable gi'owth ; while a scien- tific study of the latter involves a consideration of the laws of animal nutrition and growth, and of the chemistry of plants, so far as they are used as food. All forms of life with which we are acquainted, vegeta- ble as well as animal, manifest themselves through the breaking up of more complex into simpler compounds, accompanied by a liberation of energy. The broad distinction between vegetable and animal life is, that plants are able to appropriate the force which ex- ists in the sun's rays and use it to build up these complex compounds out of very simple, so-called inorganic mate- rials, while animals lack this power, and are obliged to avail themselves of the compounds already formed by plants. In the economy of nature, the office of the plant is to store up energy from the sun's rays in certain complex compounds, setting free oxygen in the process ; while the 1 2 MANUAL OF CATTLE-FEEDING. animal takes these compounds and utilizes the latent en- ergy which thej contain for his vital processes, the sub- stances themselves uniting again with the oxygen from which they were separated in the plant. In the plant the spring is wound up — in the animal it unwinds and gives out just as much force as was used in winding it up. The two processes supplement each other ; the w^hole is a com' plete circle. A living animal, then, is constantly decomposing and oxidizing the materials of its own body. These first break up in the cells of the body, independently of oxygen, id accordance with the laws which regulate vital phenomena and give out part of the latent energy which they con- tained. Then the oxygen of the air, carried by the blood to every part of the body, seizes on the resulting substances and burns them, more or less rapidly, producing a large quantity of heat to replace that which the body is constantly losing by radiation and otherwise, while the products of this burning are finally excreted from the body. The body is thus continually suffering a loss of material. To replace this loss, as well as to supply material for fur- ther growth, is the office of the food, which may, frona this point of view, be regarded as a vehicle for the intro- duction of supplies of force into the body. It is the object of such a book as the present one to show how much and what kind of food is needed to sup- ply the losses arising under the various conditions to which farm animals are subject. In order to do this intelligently, we need to consider : Jlrst, the nature and extent of the processes going on in the body ; second, the materials avail- able as food ; and third, the adaptation of these materials to the various purposes of feeding. The subject;, then, naturally divides itself into three parts : MANUAL OF CATTLE-FEEDING. 3 I. The General Lav7S of Animal Nutrition, or that portion of animal physiology which treats of the so-called " vegetative functions." This includes the composition of the animal body, the processes of digestion, circulation and respiration, and the production of flesh, fat, and work. n. The Composition and Digestibility of Feeding- Stuffs. m. The Feeding of Farm Animals — a consideration of the kind and quantity of food required for the various purposes for which such animals are kept. ^;^^c*i. PAET L THE GENERAL LAWS OF ANIMAL NUTRITION. CHAPTEE I. THE COMPOSITION OF THE ANIMAL BODY. § 1. Proportions of the Different Organs and Parts. The Fluids circulating in the blood and IjTiipli vessels constitute but a small part, at most not more than 7 to 9 per cent., of the live weight, and in old or very fat animals the proportion sinks as low as from 4 to 6 per cent. The digestive fluids and other secretions and fluid excretions, although they are produced in considerable quantity in the course of twenty-four hours, can hardly be taken into account as constituents of the body, since they are being produced at every instant, are formed more or less directly from the blood, and are partly re-absorbed into it or pass out of the body ; while the blood, on the other hand, al- though continually giving up material to the tissues and receiving new from the food, remains very constant in its quantity and chemical properties. The Solid Tissues. — The fresh bones constitute, ac- cording to the kind, age, and condition of the animal, 6 to 12 per cent, of its weight, the muscles and tendons 35 to 48 per 6 MANUAL OF CATTLE-FEEDING. cent., and the fat, so far as it can be mechanically separa- ted, 10 to 40 pei cent. It is to be noted, however, that the fresh bones contain 11 to 14 per cent, of water, and the muscles from 60 to over 75 per cent. The average of the results of numerous investigations made on the various farm animals gives them approximately the following composition; • Bones 9 per cent. Flesh and tendons 40 " MechanicaUy separable fat 24 *' The remaining 27 per cent, comprises the blood, hide and hair, entrails, and the contents of stomach and intestines. Fuller details regarding the proportions of the various parts in lean and fat animals of various kinds are to be found in the Appendix. It should be added that the volume and weight of the contents of the stomach and intestines are very various, according to whether the animal has received a more or less bulky fodder. For example, in some investigations made by E. v. Wolff, in Hohenheim, with sheep, the fol- lowing averages were obtained : No. of Experiments. Fodder. Average live weight per head. Pounds. Contents of Btomach and intestines. Pounds. Contents in per cent, of live weight. 3* Chiefly straw 93.8 100.1 124.2 20.9 16.0 11.2 22.3 2* Hay, with small amount of beans 15.9 6t Clover hay, potatoes, peas, and com 9.04 ♦ "Die Versuchs- Station Hohenheim," 1866-1870, p. 62. f Landw. Jahrbiicher, L, 569. MANUAL OF CATTLE-FEEDING. Grouven * found in the case of oxen : No. of Experiments. Fodder. TJ,ro Contents of weSt stomach and Contents ia per cent, of live weight. 4 Straw 1,199 1,419 199 183 16.6 7 Fattening fodder. 9.4 Fatted hogs give a less proportion, viz., 4 to 6 per cent. Lawes and Gilbert f, in iiftj-nine experiments, found the proportion of stomach and intestines, together with their content&j to range from 5.59 per cent, to 10.13 per cent, of the live weight, the average being 7.52 per cent. § 2. The Non-Nitrogenous Constituents op the Animal Body. Water. — One of the most important constituents of the animal body is water. This substance constitutes, under most circumstances, more than half of the entire weight of the animal ; it is contained in all parts of the body, and forms as essential an ingredient of the so-called solid tissues as do any of their other components. In the new-born animal, water constitutes 80 to 85 per cent, of the total weight, but during the period of rapid growth the proportion of dry matter increases and that of water diminishes, so that the mature, but not fattened, animal may contain 50 to 60 per cent, of water. In the process of fattening, the percentage of water decreases * Zweiter Salzmunde Bericht, 1864, p. 137, and Erst^r Bericht, 1862, p. 260. t Jour. Roy. Ag. Sec, Series I., XXI., 449. 8 MANUAL OF CATTLE-FEEDING. stili more, falling, according to the experiments of Lawes and Gilbert, below 50 per cent., and in one case (a very fat sheep) to 35.2 per cent, of the whole animal, or 33 per cent, of the dressed carcass. It is sometimes stated that, in fattening, the body loses water, its place being taken by nitrogenous matters and especially by fat, but the author has not been able to find any account of experiments which substantiate this view. Fat animals, it is true, contain a smaller percentage of water and a larger percentage of fat than lean ones, but this is not sufficient to prove the point, for an increase in the ahsolute amount of fat contained in an animal would cause a decrease in the relative amount (percentage) of all the other ingredients, water included. The only method by which the truth of the above view can be determined, is to compare the absolute weight of water, fat, albuminoids, etc., in lean and fat animals of the same breed and as nearly alike as possible. Such comparisons have been made by Lawes and Gil- bert,* in the follo\ving manner. Ten animals of different kinds, and in different stages of fatness, were slaughtered, and the percentages of ash, albuminoids, fat, and water in the whole animal determined, and by this means data were obtained for estimating the absolute amounts of these sub- stances in the body of a living animal whose weight was known. A large number of animals were then fattened, and, their composition before and after being estimated as above, it was easy to determine the amomit of each in- gredient which had been produced, and from this the per- centage composition of the increase in weight. * Jour, Roy. Agr. Soc. Series I., XX I., 456. MANUAL OF CATTLE-FEEDING. 9 The following table shows the average results for oxen, sheep, and hogs : Average Composition of the Increase of Live Weight in Fattening, Ash. Per cent. Protein. Per cent. Fat. Per cent. Total dry matter. Per cent. Water. Per cent. 98 Oxen 1.47 2.34* 0.06 1 7.69 7.13 6.44 66.3 70.4 71.5 75.4 79.9 78.0 24.6 348 Sheep , 20.1 80 Hogs 22.0 Average 1.10 7.26 67.8 76.2 23 8 It is evident from the method followed that the results are not absolutely accurate, but they suffice to show that in fattening, a gain of water takes place, though it is rela- tively small. The same conclusion is indicated by recent experiments by Henneberg, Kern, and Wattenberg,;]: on the fattening of sheep. They slaughtered animals in two stages of fattening, and also, at the beginning of the experiment, others which had not been fattened. The following numbers, taken from their results, show the total gain of weight by the " fat " and the " very fat " animals, and also the excess of fat and flesh contained in their bodies over that found in the unf atted ones : * Probably too high, owing to dirt in the wool, f Probably too low. if Biedermann's Central- Blatt., Jahrg. 8, p. 363 1* 10 MANUAL OF CATTLE-FEEDING. Lean, rounds. Fat. Pounds. Very fat. Poundfl, Original weight 90.53 90.53 89.54 116.45 26.91 89 10 Final weight 123 86 Gain 34.76 Gain of fat 24.51 —0.33 33 78 Gain of flesh, . . ,, 51 Total, fat and flesh 23.18 34.29 The increase of fat and flesh is, in each case, less than the total gain, showing that there was a gain of some- thing else, and making it improbable that any essential loss of water took place, especially as the flesh was found to contain almost exactly the same percentage of water in the very fat and in the lean animals, viz. : Lean 79.41 per cent. Very fat 79.02 *' Unfortunately, however, no such complete analyses of the whole animal were made in these trials as in those of Lawes and Gilbert, and hence the data which they afford are insufficient to settle the question. The dry substance of the animal body consists of organic and inorganic matter, and the former, again, of nitrogenous and non-nitrogenous materials. By organic matter, in the above sense, is understood matter which is combustible, and which, when subjected to the action of fire, disappears, leaving the irwrganic mat- ter behind as ashes. The terms are not strictly coiTect, since the ash of a MANUAL OF CxVTTLE- FEEDING. 11 piece of flesh, or of a mass of wood, was as really organ- ized^ and formed as truly a part of it, as the so-called or- ganic portion, but they are in common use with this meaning. The organic matters of the animal body are classified, according to whether they contain the element nitrogen or not, as nitrogenous or non-nitrogenous. Fat. — Of the non-nitrogenous substances fat is by far the most abundant. It is present in the blood in minute quantities, generally constituting not more than 0.1 to 0.3 per cent, of it; it exists in larger quantity in the substance of the nerves and in the bones, but is chief- ly found enclosed in special cells or tissues under the skin, on the kid- neys, omentum, and mesentery, and in the flesh between the bundles of muscular fibres. Pig. l._(Settegast). Fat The thin membrane which com- ^^^^^' poses the cell- walls of the fat- tissue is a nitrogenous sub- stance, and constitutes only 0.8 per cent, of the whole tissue when the latter is entirely filled with fat, but when this is not the case its amount may rise to 4 per cent., or over. The quantity of water in the fresh fat-tissue stands in a fixed relation to the amount of membrane (about 5 or 6 to 1), so that the quantity of water may vary from 4 to over 24 per cent., according to whether the cells are more or less laden with fat. Most of the fat-cells of the living body contain liquid, perfectly transparent fat, but its consistency varies in the different organs; it solidifies to a solid, butter-like mass more or less easily, according to whether the oily or the solid fats predominate. The appearance, also, as well as the 12 MANUAL OF CATTLE-FEEDING. smell and taste, of fat taken from different kinds of animals, or from different parts of tlie same animal, is very variable, on account of admixtures of small quantities of coloring matters and volatile substances of all sorts ; but this has almost no influence upon the elementary composi- tion of the fat, which is very constant. Schulze and Keinecke,* at the Weende Experiment Sta- tion, found twenty-eight samples of mutton, beef, and pork fat, taken from different individuals and from different parts of the body, and freed from the fat-membrane and fi'om water, to have the foUowmg composition : If ^1 Cakbow. Htdrogen. Oxygen. Av. Per cent. Max. Per cent. Min. Per cent. Av. Per cent. Max. Per cent. Min. Per cent. Av. Per cent. 11.59 11.52 11.36 Max. Per cent. Min. Per cent. Beef fat 10 6 12 76.50 76.54 76.61 76.74 76.27 11.91 11.94 12.03 12.11 12.07 12.16 11.76 11.86 11.87 11.86 11.83 11.56 11.15 Pork fat . 76.78 76.85 76.29 76.27 11.15 Mutton fat 11.00 Average of all the An- alyses in round numbers. 76.50 12.00 11.50 Other results were Fat from Carbon— per cent. Hydrogen — per cent. Oxygen — per cent. Dog 76.63 76.56 77.07 76.62 12.05 11.90 11.69 11.94 11.32 Cat 11.44 Horse Man 11.24 11.44 Versuchs-Stationen, IX, 97. MANUAL OF CATTLE-FEEDING. 13 It is evident from these figures that in all calculations regarding the gain or loss of fat bj the body, we may treat this fat, in spite of the numerous modifications which it undergoes in the various organs, as chemically identical, without falling into any appreciable error. The quantity of fat which may be laid up in the body is often enormous. For example, in the case of fattened neat-cattle and swine, the fat may make up from 25 to over -1:0 per cent, of the live weight of these animals, or from two to three times as much as all the nitrogenous substances present. In lean animals, on the other hand, the amount of fat is much less, and that of the nitro- genous substances relatively greater. Other Non-Nitrogenous Organic Substances. — All the non-nitrogenous organic substances, other than fat, which occur in the body, and are to be regarded as normal constituents of it, are very inconsiderable in quantity, al- though often of importance for the functions of the organs or fiuids in which they are found. The gastric juice (the digestive fluid of the stomach), and also the contents of the large and small intestines, and sometimes the chyle of the thoracic duct (see p. 68), con- tain lactic acid, the well-known acid of sour milk, while the juices of the flesh contain another acid — sa7'kolactic acid — isomeric* with the former. The blood, and in fact almost all the animal fluids, also contain minute quantities of one or the other of these acids. Sugar is likewise found in the blood, but at most in quantities not exceeding 0.015 per cent., except in the * Two substances are said to be isomeric when they have the same percentage composition, but different chemical properties. 14 MANUAL OF CATTLE-FEEDING. blood of the hepatic vein (the vein leading from the liver toward the heart), where the amount rises to about 0.1 per cent. The liver itself contains a considerable quantity of a sub- stance called glycogen^ somewhat resembling starch, which is continually yielding sugar by its decomposition. The sugar in the hepatic vein has its source in the glycogen of the liver. The muscles likewise contain glycogen, and also small quantities of a non-nitrogenous substance peculiar to themselves, and resembling sugar in composition and properties, called inosite. Furthermore, various non-nitrogenous organic com- pounds occur in the bile, and innmnerable such in the so- called extractive matters of the tissues and juices, that is in the mixture of substances obtained by treating the flesh, etc., with alcohol. The " extractive matters" give to meat soup its agreeable taste and smell. The weight of all these substances, however, is inconsiderable, and van- ishes almost entirely in comparison with the great quanti- ties of fat and nitrogenous matter in the whole body. § 3. Nitrogenous Organic Substances. Of the nitrogenous constituents of the body, there are three principal groups to be considered, viz., the Albu- minoids, Gelatigenous Substances, and PIorny Matters. The albuminoids are by far the most important of the three, since all manifestations of animal life are dependent chiefly on them and the organs which are composed of them, and since they furnish the material out of which the members of both the other groups are formed ; while the latter, once formed, do not appear to be capable of MANUAL OF CATTLE-FEEDING. 15 being altered back into albuminoids, or of performing the fmictions of the latter in nourishing the body. Albuminoids. — The albuminoids are found in manifold modifications in all the organs and fluids of the healthy body, except the urine, and all these modifications suffer an almost continual mutual alteration under the influence of the vital processes. Notwithstanding their diversity, however, they have many and marked characteristics in common. As their name implies (albuminoid — albumin-like), they resemble albumin or white of egg. Like it, they are des- titute of any crystalline form (amorphous). Most of them exist in at least two modifications— a soluble and an in- soluble one. In the soluble form they constitute, when dried at a gentle heat, transparent, white or yellowish solids, destitute of taste or smell, and soluble in water ; in the insoluble modification they form white, fiocculent or fibrous masses, insoluble in water, and, like the soluble forms, having neither taste nor smell. The soluble albuminoids are very readily converted into the insoluble form by a variety of means ; in some cases by heat, in others by the action of acids or other bodies, and in still others from some cause not yet known. This change is called coagulation; it is apparently only a change in the condition and not in the nature of the substance. At any rate, it is not accompanied by any change in composition. Almost innumerable varieties of albmninoids have been described, and much confusion exists as to their properties, and relations to each other. For our present purpose, however, it will suffice to indicate the three groups into which these bodies may be classified — viz. : Albumin (represented by white of Qg^^ Fih^n (repre- sented by lean meat), and Casein (the basis of cheese). 16 MANUAL OF CATTLE-FEEDING. Albumin predominates in all animal fluids, especially in the so-called chyle, in the colorless sermn (see below) of the blood, and in the fluid contents of the blood-corpus- cles, where it is tinted red by the coloring matter of the blood. It also occm-s in the juice of the muscles and in the nerves. It is distinguished by the property of coagulating when heated above a certain point. For pure albumin this point is 165° F. ; for solutions of albumin it is higher in proportion as they are more dilute. (A good example of coagulation is furnished in the boil- ing of an egg. As the heat of the boiling water penetrates the egg the albmnin changes from a transparent soluble liquid to an opaque solid w^hich no longer dissolves in water.) Fibrin. — The blood of all the higher animals, shortly after it is removed from the body, partially solidifles, and separates into two parts, the " clot " and a yellowish liquid called the serum. The serum contains albumin and the dissolved matters of the blood generally ; the clot contains an albuminoid known as hlood-fibriii, colored red by the blood-corpuscles which it has entangled within itself while coagulating. Authorities differ as to the nature of this so-called spontaneous coagulation, and for our present purpose it is not necessary to enter upon the subject. When purified, as far as possible, from adhering im- purities, blood-fibrin is a white, fibrous-looking, elastic substance, in which the microscope shows no traces of any structure, fibrous or otherwise. Flesh-fibrin^ the chief constituent of aU muscular fibres, differs from blood-fibrin in the fact that it appears in or- ganized structures in the form of variously shaped and MANUAL OF CATTLE-FEEDING. 17 grouped cells. Flesh-fibrin behaves, also, somewhat differ- ently to chemical reagents from the coagulated blood-fibrin, but, like all insoluble modifications, it is easily converted by the action of the digestive fluids into a soluble form. Casein is found in considerable quantity only in milk ; it is a product of the milk-glands and therefore not to be looked upon as a constituent of the body in general. It does not coagulate on heating ; the tenacious skin which forms on the surface of milk when it evaporates is a sub- stance altered by the action of the air. On the other hand, the casein separates almost com- pletely in a coagulated state when a small quantity of rennet is added to the milk, as in making cheese, or when the milk is gently warmed with dilute acids or various other substances, as well as in the natural souring of milk. Composition. — All the albuminoids contain, as essen- tial constituents, carbon, hydrogen, oxygen, nitrogen, and sulphur ; and these constituents are present in such con- stant quantities that it is impossible to distinguish the various albuminoids from each other by their percentage composition, samples of the same albuminoid from different sources often showing as great differences as exist between members of different groups. The following numbers show the extremes of variation : Carbon 52-54 per cent. Hydrogen , 7 " ** Nitrogen 15-17 " " Oxygen 24-21 " *♦ Sulphur 1-L5 ** " Generally the average amount of nitrogen is assumed to be 16 per cent., and the total quantity of albmninoids in a 18 MANUAL OF CATTLE-FEEBING. substance is calculated by multiplying the percentage of nitrogen foimd by analysis by 6.25 (6.25 x 16=100). The phosphorus which always accompanies the albu- minoids seems to be held only loosely as phosphoric acid, and not to be an essential ingredient of them. Gelatigenous Substances. — The gelatigenous substances constitute scarcely less of the weight of the body than the albuminoids. They form the nitrogenous organic substance of bone and cartilage, and make up the larger part of the mass of the tendons, ligaments, and connective tissue, and of the skin. By protracted boiling with water the gelatigenous substances are completely dissolved, and converted into glue. Their composition is very similar to that of the albuminoids, except that they generally contain somewhat less carbon (50 to 51 per cent.), and in case of cartilage also less nitrogen (about 15 per cent.), while the gelatigenous substance of the bones, tendons, and skin, on the contrary, is richer in nitrogen (about IS per cent.). The sulphiu* is also either entirely lacking, or is present in smaller quan- tity than in the albmninoids. Horny ^Iatters. — The horny matters are found chiefly on the outer surface of the body, either in a thin layer, as the epidermis (scarf-skin), or in well-characterized tissues, as hair, wool, horns, nails, hoofs, claws, feathers, etc. The average composition of all these tissues is very uniform : Carbon 50-51 per cent. Hydrogen about 7 " Nitrogen 16-17 ** Oxygen 22-20 " Sulphur 3-5 *' In the main, therefore, they differ from the albuminoids MANUAL OF CATTLE-FEEDING. 19 and gelatigenous substances only in containing more sul- phur, while the proportions of the remaining constituents are almost the same. AvEEAGE Composition. — It will be seen that all the important nitrogenous substances which occur in the body are very similar and, on the average, almost identical in composition with the pure albuminoids out of which they were all formed, directly or indirectly, in the processes of nutrition and growth. This agreement was also found in the investigations of Lawes and Gilbert on whole bodies of animals, already re- ferred to. In these experiments the total quantity of water, fixed mineral matters, fat, and organic substances other than fat was determined, and the nitrogen of the latter was estimated. The amount of '' organic substances other than fat " found directly, agreed almost exactly with that obtained by multiplying the quantity of nitrogen found by the usual factor, 6.25 ; in other w^ords, all the organic sub- stances other than fat were found to contain, on the aver- age, almost exactly 16 per cent, of nitrogen. In the average of all the experiments, the organic matter other than fat was found to be 11.67 per cent, of the dressed w^eight, and the amount of albuminoids calculated from the nitrogen, 11.83 per cent. This shows at once that all the nitrogenous organic matters of the body aside from the three groups already mentioned, e. ^., certain constituents of the bile, of the juice of the muscles, etc., have, on ac- coimt of their relatively small quantity, no material influ- ence on the elementary composition of the organic sub- stance of the body, and especially none on the percentage of nitrogen. 20 MANUAL OF CATTLE-FEEDING. § 4. InorganiCj or Non-volatile Matters. Amount. — The total quantity of the inorganic portion, or ash, of the animal body is, in round numbers, In neat cattle 4-5 per cent, of the live weight. *' sheep 2.8-3.5 '' '' "swine 1.8-3.0 " " In lean animals the amount approaches the maximum, in fat animals the minimum. Phosphoric acid and lime are present in about equal proportions and make up together about four-fifths of the total quantity of ash, while the other fifth consists of potash, soda, magnesia, chlorine, sulphuric acid, carbonic acid, and, to a very minute extent, of silica. The sulphur, mentioned above as forming part of all the important nitrogenous substances of the body, is not included in the ash. In the bones, as is well-known, the quantity of mineral matter (bone-ash) is especially great, and amounts, on the average, in a full-grown animal, to about two-thirds of the dry, fat-free substance of the bones. Immediately after birth, the dried bones contain only about 50 per cent., and in advanced age often as much as 75 per cent, of ash. The outer and more solid layers are always richer in ash than the inner and porous parts, es- pecially in the hollow bones. At least seven-eighths of the total bone-ash is phosphate of lime, the remainder is car- bonate of lime with small quantities of magnesia, fluorine, and soda. Besides phosphoric acid and lime, the most important inorganic constituents of the body are potash, soda, and chlorine (the two latter generally combined to form chlo- ride of sodium or common salt). Need of a Continual Supply. — The quantity of these MANUAL OF CATTLE-FEEDING. 21 substances in the various tissues and fluids, while it is very constant, is relatively small, except in the case of the bones, but they are absolutely essential constituents of all those parts of the body in which the vital processes are most actively carried on, and in which, consequently, de composition and rebuilding are continually taking place. As a consequence, they are continually excreted from the body in considerable quantities with the final products of the metamorphosis of tissue, and the vital processes would soon suffer important disturbances were not a continual, almost daily, supply provided. Salt-hunger. — Numerous experiments have shown that when animals are fed on food from which the mineral matters (salts) have been extracted as completely as pos- sible, they become sleepy, weak, especially in the extremi- ties, and finally die from lack of mineral food, although the quantity of organic food eaten and digested may be amply sufficient to sustain life. As an example of these riiay be mentioned some experi- ments made at the Physiological Institute of the Univer- sity of Munich, by Forster,* on pigeons and dogs. The pigeons were fed with starch and casein, made as free from ash as possible ; the dogs with meat repeatedly extracted with water (to remove the mineral matters) and with fat, sometimes with addition of starch. The results were the same in every case. All the animals became, after a few days, in consequence of " salt-hunger," dull and inactive ; a rapidly increasing weakness of the muscles ap- peared, particularly in the extremities, and toward the end of the experiment cramps and shivering showed a great irritability of the nervous system. ♦Zeitschr. f. Biologic, IX., 297. 22 MANUAL OF CATTLE-FEEDING. The digestion, however, as well as the utilization of the digested nutrients, was exactly the same as under normal conditions, and the animals, when killed at the end of the experiments, were found to be apparently well nourished, and with all the organs in a healthy state. We must conclude from these, and numerous other simi- lar researches, that the phenomena of dulness and weak- ness observed in all such experiments are due directly and exclusively to the lack of inorganic ingredients in the food, and that the comparatively speedy death is caused by the separation from the animal organs and juices of those salts necessary for the due performance of their functions, and their removal fi-om the body in the urine. Essential and Accidental Salts. — The greater por- tion of the inorganic matters of the body exists, in com- bination with organic substances, as an essential constitu- ent of the various tissues and juices. Strictly speaking, it forms part of the organic (or organized) portion of the body,, Its amount is very constant. Another variable and much smaller portion, which we may call accidental, exists simply dissolved in the fluids of the body, without really forming part of it. This portion can never be very great, even with an abundant supply of salts in the food, since the latter are rapidly excreted in the urine, and the more rapidly the greater their quantity ; while those salts which enter into the composition of the tissues can be ex- creted no faster than they are set at liberty by the using up of the tissue, and, in fact, even when thus set at liberty, may recombine, in part, with organic matter to form new tissue. This latter fact is particularly noticeable when the food is poor in salts. Thus, it was found in the experiments already described (p. 21) that the excretion of salts was MANUAL OF CATTLE-FEEDING. 23 least when the food was most abundant but was poorest in salts, showing that nature can be very economical and get on with a minimum. There is a limit to this, however. The excretion of salts can be diminished but not entirely pre- vented, and if the supply of salts is too small, the animal loses mineral matter continually, and sooner or later dies. Practical Conclusions. — In practice, in the feeding of mature animals intended to be kept in a medium condition, or to be fattened, a lack of the necessary mineral matters is scarcely ever to be feared. They are, indeed, generally present in large excess. Only common salt is in certain respects an exception, as will be explained more fully below. The opinion is indeed somewhat prevalent that a lack of phosphate of lime in the fodder may be the immediate cause of the disease, prevalent among cattle in some neighborhoods, called rickets. This explanation is, however, at most, only valid in case this lack was experienced by the animal from its earliest youth up. In the case of full-grown and healthy animals, the lack of phosphate of lime cannot well be the cause of the disease, since experiment has shown that such animals, when they are insufficiently supplied with this substance, die in a comparatively short time, and before any essential change takes place in the composition of the bones. Young and rapidly-growing animals naturally need, both relatively and absolutely, a greater quantity of phosphate of lime than old and full grown ones. In the feeding of milk cows, too, regard must be had to the quantity of phosphate of lime in the fodder. (See Part III., chapters Y. and YI.) Uses of Common Salt. — As mentioned above, salt occupies, to a certain extent, an exceptional position. 24 MANUAL OF CATTLE-FEEDING. Besides its strictly physiological functions, it is of use in facilitating the passage of the albuminoids of the food f roni the digestive canal into the blood, and to a certain extent in facilitating the circulation and thus increasing the energy of the vital processes. For this piu'jDose a certain excess of salt seems to be necessary, which circulates rapidly through the body, and is excreted in the urine in quantity corresponding to the amount taken. This need of salt is especially manifest in certain kinds of herbivura, and particularly in such as, like our domestic animals, are largely stall-fed and, by means of abundant fodder, are caused to produce largely either flesh and fat, milk, or work. To this may be added that many fodders in common use, such as potatoes, roots, grains, etc., are comparatively poor in sodium chloride and rich in potash salts, which latter, it has been found, cause an increased excretion of salt tlu'ough the urine. In view, then, of the absolute demand for a certain amount of salt for the preservation of life and the great advantages of a certain excess of it, it is plain that it is te be regarded not as a iuxuiy but as a necessity. // •5^« /# ^^- CHAPTEE 11. COMPONENTS OF FODDERS.— NUTRIENTS. § 1. Definitions. Nutrient, Fodder, Ration. — In the preceding chapter we have seen that the animal body, in spite of the great complexity of its structure, may be considered, in a general way, as composed of nitrogenous and non-nitrogenous or- ganic substances, and of mineral matters. Since, now, these substances are being constantly de- stroyed in the body in the performance of the vital func- tions, it is necessary that the animal should receive from without a supply of substances identical with or similar to those destroyed, and which can be assimilated by the tis- sues and fluids of the body to replace those lost and enable the vital actions to continue. Any single chemical compound, such as albumin, fat, starchj sugar, etc., which is capable of aiding to replace this loss is called a nutrient. Such substances do not occur in a pure, unmixed state in nature, but are found in various forms and proportions in all fodders. By a fodder, or feeding-stuff, we imderstand any natu- ral or artificial product which is used as food for animals ; e. g., hay, oil cake, roots. Since the animal organism not only contains various nitrogenous and non-nitrogenous substances, but contains them in proportions varying only within narrow limits ; and since the rate at which each is destroyed in the body 26 MANUAL OF CATTLE-FEEDING. is also fixed witliin certain limits ; it is plain tliat tlie food which the animal receives must also contain the various nitrogenous and non-nitrogenous nutrients in proper pro- portions. A fodder usually contains several or all of the groups of nutrients, but mav not contain them in the proper pro- portions to satisfy the needs of the organism. Thus, in the examples given above, good hay contains all the groups of nutrients in proper proportions, and will sus- tain an herbivorous animal indefinitely ; while oil cake and roots contain an excess, the one of albuminoids, the other of bodies of the starch or pectin groups, and so, if capable of sustaining life, do it with a great waste of the one or the other material. They are one-sided foods. By combining several one-sided foods, we may prepare a mixture which shall contain all the groups of mitrients in proper proportions and be capable of sustaining an animal economically. Such a mixture we may call a ra- tion or a comjylete food. The proportions of the various nutrients in the common fodders and the proper combining of fodders to form ra- tions suitable for various purposes will be treated of in Parts II. and III., and we shall concern ourselves here only with the occurrence and properties of the nutrients. These it is necessary to consider in order to a proper un- derstanding of the processes of digestion and assimilation. The nutrients are divided into three groups, corresponding to the three groups of substances in the animal body, viz. : nitrogenous, non-nitrogenous, and mineral substances. § 2. Nitrogenous Nutrients. Protein. — The predominant nitrogenous constituents of plants resemble closely, in all important particulars. MANUAL OF CATTLE-FEEDING. 27 the albuminoids of the animal body, and have, like them, been called albuminoids or protein bodies. The name protein was used by Mulder to designate a supposed substance which formed the basis of all the albuminoids. The word is no longer used in this sense, but is very commonly met with as a collective term for all the albuminoids, and we shall thus use it in the present work. The vegetable albuminoids which have as yet been in- vestigated may be divided into tliree groups, albumin^ casein^ 2iW^ fibrin^ having more or less resemblance to the corresponding groups of animal albuminoids, though it is doubtful if the two are identical. Vegetable Albumin appears to occur chiefly in the, young and growing parts of plants, while in the older parts it is converted into other forms of protein. It i? contained, dissolved in small quantities, in the sap of fresh plants, and coagulates when the sap is heated. Vegetable albumin is soluble in cold water, in dilute potash solu- tion, and in dilute acetic acid ; it is insoluble in alcohol, and is very similar in all its properties to animal albumin. Its composition varies somewhat according to the source from which it is derived. The fol- lowing table shows the extremes of variation : Carbon . . . Hydrogen Nitrogen . Oxygen . . Sulphur. . Vegetable albumin. Per cent. 52.3-54.3 7.1- 7.7 15.5-17.6 20.6-23.0 0.8- 1.6 The composition of animal albumin is not far from the average for Tegetable albumin, but the identity of the two is, at best, doubtful. 28 MANUAL OF CATTLE-FEEDING. Vegetable Casein. — If wheat iloiu' be made into dough, and the dough kneaded in a stream of water, the starch of the flour is washed out, and a sticky mass remains^ known as crude wheat-ghiten. The crude ghiten thus obtained is a mixture of at least four albuminoids, and contains, besides, some starch and fat. When treated with dilute (60 to 80 per cent.) alcohol at ordinary temperatures, three of these albiuninoids are dissolved, while the fourth, called gluten-casein, re- mains behind, together with various impurities. The same or a very similar substance is also contained in rye, barley, and perhaps in buckwheat, and in the " oil seeds ; " while oats contain an albuminoid having some of the prop- erties of gluten-casein but more closely resembling the legumin about to be described. In addition to gluten-casein, two other bodies belonging to the casein group have been described, viz. : tegicmin, the chief albuminoid of the seeds of the legumes (peas, beans, etc.), and conglutin, contained in almonds and in maize (?) The properties of these albuminoids, and in particular those of legu- mi?i, resemble very closely those of animal casein. Legumin is in- soluble in water. It is, however, quite soluble in water containing small quantities of basic phosphates, especially of potash, and hence warm water extracts legumin from the seeds of the legumes, since the latter contain soluble phosphates. Such a solution of legumin is not coagulated by heat, but is by acids, and according to one authority by rennet. Legumin is insoluble in either strong or dilute alcohol, but very readily soluble in dilute potash solution, and somewhat soluble in dilute acids. The reactions of gluten-casein, as well as those of con- glutin, are very similar to those of legumin. The composition of these albimiinoids, like that of all others, varies more or less accoi'ding to their source and MANUAL OF CATTLE-FEEDING. 29 mode of preparation, owing largely to the great difficulty of obtaining them in a pm-e state and in part perhaps, to the non-identity of substances bearing the same name but derived from different sources. The following table shows some of Ritthausen's results.* Gluten-casein. Per cent. Legumin fbom CONGLUTIN FBOM Oats. Per cent. Peas. Per cent. Beans. Per cent. Maize. Per cent. Sweet almonds. Per cent. Carbon 52.70-53.16 6.95- 7.15 16.70-17.21 21.92-22.18 0.93- 1.27 51.63 7.49 17.45 22.64 0.79 51.48 7.02 17.13 23.97 0.40 51.48 6.96 14.76 (?) 26.85 0.45 51.41 7.19 17.72 ■23.C8 50.44 Hydrogen Nitrogen 6.85 18.61 23.67 0.43 Vegetable Fibrin. — When crude wheat gluten is treated with alcohol in the preparation of gluten-casein, as above described^ a solution is obtained from which an albuminoid known as gluten-fibrin may be prepared as a tenacious, translucent substance of a brownish-yellow color. It is insoluble in water or absolute alcohol ; soluble in dilute alcohol, in dilute acids, and in dilute potash solution. When heated, it is con- verted into an insoluble modification, which is not dissolved by dilute acids or alkalies. The same or a similar substance is contained in barley and maize. The corrvposition of vegetable fibrin, like that of the other albuminoids, varies more or less. Kitthausen ob- tained the f ollowins: results : * Die Eiweisskorper der Getreidearten, etc. , 1873, and Jahresber. Agr. Chem., N. F., I., 168. 30 MANUAL OF CATTLE-FEEDING. Carbon. . . Hydrogen Nitrogen. . Oxygen... Sulphur. . From wheat. Per cent. 54.31 7.18 16.89 20.61 1.01 100.00 From barley. Per cent. 54.55 7.27 15.70 22.48 100.00 From maize. Per cent. 54.69 7,51 16,33 20,78 0.69 100.00 Mueedin and Gliadin. — Besides gluten-casein and glu- ten-fibrin, wheat gluten contains two other albuminoids, viz. : nnicedin, and gliadin or vegetable glue. Mueedin, when freshly prepared and containing water, is a yellowish- white, slimy substance, somewhat translucent and with a silky lustre. It is soluble in dilute alcohol, but insoluble in strong alcohol, which precipitates it from its solutions. Its behavior to water is peculiar. It is scarcely soluble, but when agitated with water, can be suspended in it, forming a turbid, slimy fluid, which, on long standing, deposits the mueedin unaltered. The same results are obtained if the water is warmed instead of stirred. Continued boiling with water decomposes mueedin, and alters most of it into an insoluble substance, Gliadin very closely resembles animal glue in its properties. It is soluble in both weak and strong alcohol, in alkalies, and in acids. In cold water it swells up like glue ; prolonged boiling with water decomposes it. The composition of mueedin and gliadin obtained from wheat was found by Eitthausen to be : Carbon , . . Hydrogen Nitrogen . Oxygen. . „ Sul]>hur . . Mueedin — Per cent. Gliadin — Per cent. 45.11 52.67 6.90 7.10 16,63 18.01 21.48 21.37 0.88 0.85 MANUAL OF CATTLE-FEEDING. 31 Mucedin is also found in rye and barley, and gliadin in oats. Other Albuminoids. — It will not have escaped notice that in the above paragraphs we have coniined om-selves chiefly to a consideration of the albuminoids of the cereal grains and the legumes. This is simply because these are the only vegetable prod- ucts which have been mvestigated with any degree of completeness. Doubtless other feeding-stuffs would be found to contain still other varieties of protein, were they investigated, but at present we know little or nothing re- garding them. Comparative Value in Nutrition. — While the vari- ous albuminoids of the vegetable world vary not inconsid- erably in their composition, especially as regards carbon and nitrogen, they still show such strong general resem- blances, both in composition and properties, to each other and to the animal albuminoids, that we must consider them all as closely related bodies. Indeed they seem capable, to a certain extent, of conversion into each other in various ways. Whether the various vegetable albuminoids are equally valuable as nutrients, are assimilated and formed into part of the body with equal ease, we are unable to say, owing to the entire lack of experiments on the subject. It is, perhaps, questionable if they are, but the differences, if they exist, are probably not great, and for the present we must consider them all as equivalent, so far as they are actually digested. The recent experinients of Wildt - and of E. v. Wolff f on swine seem also to show that the animal albuminoids con- ♦ Landw. Jahrbucher, VI., 177. f Ibid., VIII., 223. 32 MANUAL OF CATTLE-FEEDING. tained in dried blood and flesli-meal (the residue fi'om tiie preparation of "Extract of meat,") are equivalent in nutri- tive effect to vegetable albuminoids. It is possible tliat we ought to regard gliadin as forming an exception to the equivalence of the albuminoids on ac- count of its great likeness to animal glue, or gelatin, the latter having been shown by Yoif^ to be incapable of per- forming all the functions of protein in the food. Importance. — This close mutual relation and easy con- vertibility of the albuminoids has the highest significance for animal nutrition. As we have seen, the most important solid components of the animal body are the albuminoids and related bodies. It is these which constitute its muscles, tendons, nerves, in fact all its working machinery. I^ow, so far as we know, the animal organism has no power to originate a particle of these substances. Its sole source of them is, in the herbivora directly and in the carnivora indirectly, the albuminoids of the plant. These, by virtue of their great similarity to the animal al- buminoids, are readily altered into them and become part of the body. They are hence indispensable elements of any food, and likewise the most important, smce, while they can, to a certain extent, take the place of the non- nitrogenous nutrients, none of the latter can possibly re- place the albuminoids; and they are of all the greater importance because, while the animal body is, to so large an extent, composed of them, they are found in compara- tively small quantity in most parts of plants. Evidently, then, the proportion of albuminoids which a fodder contains is an important element in determining its * Zeitschrif t f . Biologie, VIII., 297. MANUAL OF CATTLE-FEEDING. 33 value ; and those fodders which contain them in the largest quantity are, other things being equal, the most valuable, since the albuminoids are the most expensive ingredients to produce. Occurrence in Plants. — This is not the place for a discussion of the composition of the various fodders, but a few general considerations regarding the distribution of the albuminoids in the plant may not be out of place. In the plant, as in the animal, life manifests itself chiefly through the albuminoids, and consequently all young and growing plants and parts of plants contain them abundantly, while in the older portions, which have for the most part finished their growth, they are present in much smaller proportion, both owing to the increase of other substances, chiefly woody-flbre, and an actual transfer (translocation) of albmninoids to other parts of the plant. This is one reason of the greater nulTitive value of young grass and green fodder in general, of hay cut while still young, etc. (See, however, page 299.) In mature plants the albuminoids tend to accumulate in the seeds. Thus the grains, beans, peas, etc., contain large quantities of albuminoids and owe to them, in a large meas- ure, their value as fodder, while the plants on which they grow, if allowed to stand till the seed is ripe, become cor- respondingly impoverished in these compounds. In the case of the cereals, it is the seeds which we desire, and hence we allow the plant to mature. On the other hand, in the case of the grasses, belonging to the same natural family {(jraimnecB)^ we use the whole plant as fodder, and hence cut it before the seed matures, because, although the whole amount of albuminoids is not decreased in ripening, it is largely stored up in the seeds, and these are mostly lost in the processes of curing, while 3* 34 MANUAL OF CATTLE-FEEDING. such as are retained, owing to tlieir small size, escape mas- tication and are not digested. The proportion of albuminoids in the same species of plants and in the same parts of the plant differs according to the quality of the soil on which it is grown, the manur- ing, the weather, and other circumstances, so that it is only by means of numerous analyses that the average composi- tion of any fodder can be ascertained. A discussion of these points and of the results of analyses of the more im- portant fodders will be found in Pait II. Other Nitrogenous Constituents of Plants. — Vari- ous nitrogenous substances not belonging to the albumi- noid group have been found in plants. For our present purpose, we may divide them into f om- classes : 1. Nitrates^ nitrites^ and ammonia salts; 2. Pej)tones ; 3. Alkaloids; 4. Amines, amides, and amido-adds. Nitrates, Nitrites, and Ammonia Salts. — These sub- stances usually occur very sparingly in plants, though beets, and probably other root crops, contain considerable quan- tities of them, and maize also frequently contains a not in- considerable amount of nitrates. These substances, how- ever, need hardly be taken into accomit here, since tliey have no nutritive value. Peptones. — Recently, v. Gorup-Besanez has shown (^^?*. J)eut. Chem. Ges., 1874, p. 1478) that the seeds of the vetch contain a ferment capable of converting starch into sugar and albuminoids into peptones,* and a similar substance has since been found in other seeds. It is highly probable that, ♦ See p. 59. MANUAL OF CATTLE-FEEDING. S5 during germination, these ferments act on tlie albuminoids of the seeds, converting them into peptones and so facilitat- ing their translocation into the young plant. How exten- sively or in what amount peptones are to be found in plants, we have no certain knowledge. Alkaloids. — The term alkaloid (alkali-like) is applied to a class of organic bodies possessing more or less marked alkaline characters, a bitter taste, and poisonous or nar- cotic qualities. Morphine, strychnine, and nicotine, are common examples. These bodies, though quite widely distributed in the vegetable kingdom, occur in few of our ordinary fodder plants, the principal one being the lupine. Siewert {Jahresher, f. Agr. Chem.^ 13-15, II. 6) found in the seeds of the yeUow lupine 0.6 per cent, of alkaloids, and in those of the blue lupine 0.63 per cent., and H. Schulze {Lomdw, Jahrbuche7\ YIII., 37) obtained only 0.39 per cent. Amines, Amides, and Amido-acids. — By these names the chemist understands certain nitrogenous organic sub- stances, having a more or less close chemical resemblance to ammonia. When solid, they are generally crystalline and soluble in water, and pass easily through a moist membrane by the process of liquid diffusion, differing m these respects from the albuminoids, many of which are slightly or not at all soluble in water, and all of which are non-crystalline, and diffuse with extreme slowness. Most of them, when boiled with dilute acids or alkalies, give off their nitrogen, wholly or in part, as ammonia. The first one to be discovered was asparagin (amido- succinamic acid) by Yauquelin and Eobinet in 1805, in asparagus shoots. The same body has since been found in a large number of plants or parts of plants, and appears to be quite widely distributed in the vegetable kingdom. 36 MANUAL OF CATTLE-FEEDING. Several other substances belonging to the same class have also been isolated. Scheibler * discovered betain (tri-m ethyl gljcocoll) in mangolds, v. Gorup - Besanez f found leucin in germinating vetches, Schulze and Urich if have sho^\^l that glutamin is contained m mangolds, and the same body, along with some tyrosin, was found by Schulze and Barbieri § in germinating squash seeds, and it is highly probable that other similar bodies will yet be isolated. Functions in the Plant. — The investigations of Pfeffer || on asparagin showed that this body was abundantly formed, during the germination of leguminous plants, by the split- ting up of the protein of the seed, and, after being dissolved in the water always present and thus transferred to the young plant, was reconverted into protein. That is, it served, by virtue of its solubility and diffusibility, to render available to the plant the insoluble albuminoids of the seed. Later researches by E. Schulze, ^ and especially by Borodin, ^^ seem, however, to show that the formation of asparagin is not limited to germination, but that the trans- fer of protein from one part of the plant to another which is continually taking place during growth is also effected by the agency of this and other amides. Borodin also believes that asparagin (and other like bodies ?) is being continually produced in the living plant. /Vccording to him, the respiration of the plant takes place ♦ Zeitschrift fiir Riibenzucker- Industrie, XVI., 229. f Ber. Deut. Chem. Ges-.VIL, 147. IVersuchs-Stationen, XX., 193. § Landw. Jahrbiicher, VI., 681. I Jahrbiiclier fiir Wiss. Botanik, VIIL, 530. 1 Landw. Jahrbiicher, VII. , 411. ** Botanische Zeitung, Jahrg. 86, Nr, 51 and 52. ~ MAlSrUAL OF CATTLE-FEEDING. 37 at the expense of the albuminoids of the protoplasm, which are decomposed with formation of asparagin. Under nor- mal conditions, the latter is regenerated to protein, but under certain circumstances it may accumulate in the plant. According to Schulze, various amides are formed in this process, some of which are rapidly regenerated, while others are utilized but slowly, and hence accumulate in comparatively large quantities. This view is supported by the results of Kellner,* who found a considerable amount of amides in a large number of growing plants. His experiments were made chiefly on fodder plants, in some of which over 30 per cent, of the total nitrogen was found to exist in amide form, but con- siderable quantities of these bodies were also found in the green parts of several species of trees. Furthermore, Schulze and Urichf have shown that beets, and, presumably, other roots, contain large quanti- ties of amides, and that in the second year's growth they pass into the plant and serve as a source of protein. Amides have also been f oimd in considerable amounts in potatoes, where they doubtless perform a similar function. It is but recently that investigation into the proportion of amides in fodder-plants has been begun, and our knowl- edge of the extent of their occurrence is still quite limited. In view of the importance of the matter, it is earnestly to be desired that it should receive a speedy and thorough in- vestigation, extending at least so far as to determine the average proportion of albuminoids and non-albuminoids in our common feeding-stuffs. * Landw. Jahrbiicher, VIII., I. Supplement, 243. f Versuchs-Stationen, XX., 214. 38 MANUAL OF CATTLE-FEEDING. ? 3. NON-NlTKOaENOUS NUTRIE^TS. Carbhydrates. — The chief substances composing this group of non-nitrogenous nutrients are cellulose, or %ooody- fl)re ; starch', dextrine', cane, (/''^J>^^ riiilk, and fruit sugar ; and the gums. " These bodies, especially cellulose and starch, form by far the larger share of all the dry matter of vegetation, and most of them are distributed through all parts of plants." They owe their name to the fact that they all contain, besides carbon, the elements hydrogen and oxygen in the proportions in which the latter exist in water. This similarity of composition and their ready transformation into each other, both artificially and in the plant, show that they are nearly related chemically. Cellulose. — All plants consist of cells or microscopic closed sacks or tubes adhering together. The walls of these cells are composed of cellulose, and hence the latter is a constituent of all vegetable tissue, constituting, as it were, its frame- work. In those parts of the plant where greater strength is needed, the originally thin walls of the cells increase greatly in thickness, and often become im- pregnated with a harder substance or substances known as lignin, making them still tougher. This is especially the case with the stems. Foliage, and the husks, etc., of fruits, also contain much cellulose. Projperties. — Pure cellulose is an odorlesc and tasteless solid, varying somewhat in appearance, according to its source, but usually white in color, and with a silky or horny lustre. Cotton, flax, and hemp, and cloth and unsized paper made from them are examples of nearly pure cellu- se. It is distinguished from the other bodies of this group 3IA]SrUAL OF CATTLE-FEEDING. 39 by its slight solubility ; neither dilute acids nor alkalies, water, or any of the ordinary solvents, dissolve it. Hence, it may be obtained by acting on vegetable matter with various solvents till all other substances are removed. If cellulose be exposed for some time to the action of strong oil-of -vitriol, or be boiled for some hours witli dilute acids or alkalies, it is converted first into dextrine and then into grape-sugar. If treated with iodine and then with strong sulphuric acid, it assumes a deep-blue color. This reaction serves to identify cellulose under the microscope. CoiTvposition. — Pure cellulose has exactly the same com- position as starch, viz. : Carbon 44.44 per cent. Hydrogen 6.17 " Oxygen 49.39 ** 100.00 As intimated above, however, it is seldom found pure, except in the young and tender parts of plants, but is usually more or less impregnated with substances to which the collective name of lignin has been given, and the follow- ing composition assigned : Carbon 55.3 percent. Hydrogen „....,... 5.8 *' Oxygen 38.9 " 100.0 This is, however, simply the inferred composition of what is left after cellulose has been removed, and not the result of direct analysis. But it is certain that lignin (using the name in a collective sense) is richer in carbon than cellulose, and as a membrane becomes impregnated with the former, its percentage of that element increases. 40 MANUAL OF CATTLE- FEEDING. Digestibility. — Cellulose was long thought to be indiges- tible. Haubner * was the first to show that this belief was er^ roneous, and that the ruminants were capable of digesting large quantities of this substance. His results have since been verified in innumerable digestion experiments, which have shown that cellulose forms an important ingredient in the fodder, not onlj of rmninants, but of all om- herbi- vorous domestic animals. The proportion of cellulose which is digested varies very considerably according to the kind and quality of the fodder and the species of animal to which it is fed. Of the cellulose of the ordinary coarse fodders, fi'om about 30 to 70 per cent, is digested by ruminants, while the cellulose of the cereal grains seems much less digestible. In general, the younger and more tender a feeding-stuff is, the greater is the amount of cellulose which is digested, while in old and woody plants, in which much lignin is formed, its digestibility is considerably less. The lignin itself appears to be entirely indigestible. Determination. — The amount of cellulose in a fodder is usually determined by successively boiling the finely divided material with dilute acid and dihite alkali, and washing with alcohol and ether. These solvents remove the other constituents of the fodder and leave the (impure) cellulose behind. The residue, after deduction of the small quantities of ash and albuminoids which it still con- tains, is designated as crude fibre. It is by no means pure cellulose, but is chiefly a mixture of the latter with lignin. The crude fibre obtained from * Amts- und Anzeigeblatt f . d. landw. Vereine des Konigreichs Sachsen, 1854, Nr. 6 ; also, Zeitschr. f. D. Landw. 1855, 177. MANUAL OF CATTLE-FEEDING. 41 different fodders according to tliis method has a varying appearance and composition ; the crude fibre, e. g., pre- pared from hay and straw, contains 45 to 46 per cent, of carbon, while that fi'om clover hay and the straw of the legumes contains 48 to 49 per cent, of the same element ; that is, the latter is richer in lignin than the former. It is evident from these considerations that the crude fibre is not a definite body, but a variable mixture of several substances. The method just described is, indeed, simply a conventional one, agreed on by chemists for lack of a better, and the term crude fibre simply means the residue obtained by treating the fodder in the prescribed manner. The results, especially when combined with digestion ex- periments, are of great value, but it is still much to be re- gretted that no more accurate method has yet been devised. Starch. — Next to water and cellulose, starch is the most abundant substance in the vegetable world, being found in all plants and in almost all parts of them. It appears to be first formed in the gi-een leaves, as the product of the reduction of the carbonic acid of the air under the in- fluence of sunlight, and from thence to be distributed, by a process of solution and redeposition, to all the organs of the plant. It is found in large quantity in the seeds of the cereals, wheat, e. g.^ containing 61 to 76 per cent, of it in the dry substance, and constitutes a large proportion of the dry matter of potatoes and other tubers.* Properties. — Pure starch is an odorless and tasteless white powder, which, when examined under the micro- scope, is seen to consist of minute organized grains. These starch grains are formed, in the plant by a process of * The artichoke and some other tubers contain, instead of starch, a body closely resembling it, called inulin. Inulin exists in plants both as a liquid and in grains. It gives no coloration with iodine. 42 MANUAL OF CATTLE-FEEDING. growth, and vary in size and appearance according to the species of plant which produces them, so tliat starch from different som-ces can be readily distinguished. They are composed of two substances — a skeleton of a material resembling cellulqse and called starch-cellulose^ and a more soluble substance called granuloses which constitutes by far the larger part of the grains. A characteristic property of starch is that, when brought in contact with a minute quantity of iodine in solution, it assumes a beauti- f ul blue color. This property seems to reside in the granu- lose, since, if this be removed by solvents, the residue gives no longer a blue but a yellow color with iodine, like ordinary cellulose. Starch is insoluble in cold water so long as the grains remain whole. If they are crushed and ground very fine with water, a minute quantity is dissolved. Wlien heated with water nearly to boiling, the grains swell and burst, absorbing water and forming a jelly-like mass, but very little starch is really dissolved by this treatment. Starch, like cellulose, may be converted into dextrine and grape-sugar by boiling with acids or alkalies, but much more readily. The same transformation may be effected by dry heat, and by the action of diastase,"^ the ferment of malt, as in the preparation of beer and spirits. It is also rapidly dissolved and converted into sugar by the action of the saliva of the mouth and by the pancre- atic juice, and is, indeed, one of the most important ol the non-nitrogenous nutrients, owing to its abimdance and the comparative ease and completeness with which it is digested. * Diastase produces a peculiar kind of sugar called maltose^ instead of grape-Bugar. MANUAL OF CATTLE-FEEDING. 43 The composition of dry starch is the same as that of cellulose, viz. : Carbon 44.44 Hydrogen 6.17 Oxygen , 49.39 100.00 In the air-dry state it contains 12 to 20 per cent, of water. Dextrine seldom has Leen found in plants, at least in any considerable quantity, and is chiefly interesting in this connection on account of its relations to starch and sug-ar. It is prepared commercially in large quantities, under the name of British gum, by the action of dry heat on starch. It is formed in the same way from starch during the baking of bread, and is an important ingredient of food prepared by cooking materials containing starch. It appears to be entirely digestible. The Sugars. — There are four principal kinds of sugar, viz. : cane-sugar^ obtained from the juice of the sugar-cane, the sugar-beet, sugar-maple, and other plants, and forming the ordinary sugar of commerce ; milk-sugar^ occurring in the milk of mammalia ; and grape-sugar and fruit-sugar, usually occurring together in the juices of plants and sweet fruits and in honey. Grape-sugar is also known as. glucose and dextrose, and fruit-sugar as levulose. These sugars have the following composition : Carbon. Per cent. Hydrogen. Per cent. Oxygen. Per cent. Cane-sugar ) Milk-sugar i" Grape-sugar \ Fruit-sugar J 43.11 40.00 6.43 6.67 51.46 53.33 44 MANUAL OF CATTLE-FEEDING. They all resemble, in a general way, cane-sngar in tlieii properties, though they are by no means identical. For our present purpose, it is sufficient to say that they are all readily soluble in water, and hence easily digestible. They are important nutrients, being formed in large quan- tities, in digestion, from other carbhydrates, though in the ordinary fodders they occur in only small quantity. The Gums. — Another group of substances of consider- able importance is the gums, of which gum-arabic may be taken as a representative. They are found in small proportions in various vegeta- ble products, and in considerable quantity in the ordinary bread grains. They appear to be digestible by domestic animals, but of their value as nutrients w^e know as yet but little. Probably, however, they are practically about equivalent to starch. Mutual Relations of the Carbhydrates. — The close relationship between the several members of this group of substances which is indicated by their analogous composi- tion is shown still more plamly both by their ready con- version one into another, in nature and in the laboratory, and by their behavior to various reagents. In the plant, starch seems to be the first formed, and from it all the other carbhydrates are produced, while these may be converted back again into starch. In germination, the starch of the seed is converted into dextrine and sugar, which are carried in solution to the young plant, there to form cellulose or be reconverted into starch. In older plants, cellulose may be dissolved or con- verted into gum or vegetable mucilage. In the laboratory, all the various carbhydrates are finally converted by heat or by boiling with acids or alkalies, first into dextrine and then into some form of sugar. MANUAL OF CATTLE-FEEDING. 45 The close relationship between starch and cellulose is also shown by their behavior toward iodine. As we have seen, starch is colored blue by this reagent, while cellulose requires the addition of sulphuric acid (or one of several other substances) to produce the blue color. It is only the granulose of starch, however, which gives a blue with iodine, while the starch-cellulose behaves like ordinary cellulose, and, on the other hand, J. Ktilin "^ has shown that the cotyledons of the flax-seed contain a form of cellulose which is colored blue by iodine alone. Indeed, the most recent investigations seem to show that there is a numerous series of carbhydrates, varying from the most insoluble and resistent to the most soluble and easily attacked forms, and capable of mutual intercon- version in the plant and, to a certain extent, out of it. The Pectin Substances. — This group includes a nmn- ber of bodies of rather uncertain composition, which are the characteristic ingredients of fi-uit-jellies. They are found in ripe fi'uits, and, together with sugar, constitute the larger part of the non-nitrogenous organic matter of the common root crops. Uncooked fruits and roots are supposed to contain a body caUed pectose, which, on boil- ing with water or exposure to heat, is converted into pectin, which is soft and soluble in water. It is this change which takes place in the cooking of fruit. By further heating, the pectin is converted into pectic and pectosic acids. These substances are insoluble in cold water, and constitute the essential part of fruit-jelly. Pec- tosic acid is soluble in boiling water, and hence most jel- lies become liquid on heating ; on cooling, its solution gela- tinizes again. Pectic acid is insoluble, even in boiling water. * Emahrung des Rindviehes, 6th ed. , p. 49. 46 MANUAL OF CATTLE-FEEDING. By long-continued boiling, all these bodies are converted into metapectic acid, which is quite soluble and has a sour taste. All these bodies are digestible, and are not unimportant as nutrients. They probably play much the same part in nutrition as the carbhydrates. The Fats. — Composition. — The fats found in plants have essentially the same composition as that possessed by those occurring in the animal body, and already noted on page 12, viz., on an average : Carbon , 76.5 per cent. Hydrogen 12.0 " Oxygen 11.5 " 100.0 It will be noticed that these nutrients differ from those hitherto considered in containing a much larger proportion of carbon and a much smaller one of oxygen. They con- sequently require much more oxygen for their complete combustion and give out about two and one-half times as much heat in burning as the carbhydrates, a fact of great importance in connection wdth the production of animal heat, and which will be treated of more fully in a subse- quent chapter. Occurrence. — Fat is found in small quantities in almost all plants. In roots we find 0.1 to 0.2 per cent. ; in hay and straw, 1.0 to 3.0 per cent. ; in the cereal grains, 1.5 to 3.0 per cent., except in oats, which contain as much as 6 per cent. ; and in maize about 4 to 9 per cent. It is especial- ly, however, in the seeds of certain plants that fat or oil occurs. The seeds of flax, hemp, colza, cotton, and nmnerous MANUAL OF CATTLE-FEEDING. 47 otvier plants, contain from 10 to 40 per cent, of oil, accom- panied generally by a considerable quantity of protein. The oil forms an article of commerce, and is commonly obtained by simply pressing the seeds. By this process, however, it is impossible to separate all the fat, and in the residue of the manufacture — oil cake, rape cake, cotton-seed cake, etc. — there is left a consider- able amount (8 to 12 per cent.) of oil, together with nearly all the albuminoids, and hence, owing to the importance of both classes of nutrients, these residues constitute most valuable fodder materials. Sometimes the oil is extracted by means of solution in bisulphide of carbon instead of by pressing. In this case the residue is valuable chiefly on account of its albuminoids, the fat content being reduced to from 2 to 4 per cent. Value. — In the ordinary fodder of our domestic animals fat plays a rather subordinate part, but in rapid fattening it is a most important aid, though, as we shall see, it is by no means the sole source of fat to the animal body. In addition to its direct nutritive effect, it also aids in the digestion and resorption of the important albuminoids. I 4. Inorganic Nutrients. These comprise the substances found in the ashes of plants — the so-called inorganic or mineral constituents. The need of these in the animal organism and their func- tions, so far as known, have been already sufficiently spoken of in Chapter I. In all ordinary cases a ration which contains sufficient organic nutrients will also contain an abundance of the inorganic, so that commonly no special consideration of the quantity of the latter is necessary, with the exception of common salt, which, for reasons already 48 MANUAL OF CATTLE-FEEDING. given, is needed in larger amoimts than those contained in most fodders. Sucli being the case it is not necessary, for the purposes of the present work, to do more than mention these sub- stances. g 5. Fodder Analysis. In the preceding sections we have mdicated briefly the occurrence and properties of the most important nutrients. It only remains to describe, in a general way, the usual methods of determining the amount of these present in any fodder. In the present state of our knowledge it is impossible, even were it necessary, to separate and determine all the multitudinous substances which may occur in a fodder, and we must content ourselves with distinguishing the several groups of nutrients. Albuminoids. — The amomit of albuminoids in a fodder has generally been foimd by multiplying its content of nitrogen by 6.25, it being assumed, first, that all the all:)u- minoids contain 16 per cent, of nitrogen, and, second, that no other nitrogenous substances are present. Neither of these assumptions being, as we have seen, strictly true, it follows that the result can only be approxi- mate, and in view of this fact it is designated as crude protein. Of the two sources of error arising under the above as- sumptions, the second is the more serious. It is only within a very short time that feeding-stuffs have begun to be ex- amined for amides, but the results already obtained show that these bodies are to be found far more extensively, and in greater quantity, in feeding-stuffs than was before sus- pected. This is especially the case with those fodders MANUAL OF CATTLE-FEEDING. 49 which, like hay, and coarse fodders in general, are cut when still immature, and with roots; while the grains appear to contain practically all their nitrogen in the form of protein. In the present state of our knowledge a simple determi- nation of the total nitrogen of a fodder is not sufficient, but either the amide-nitrogen must be determined or the protein nnist be separated from the other nitrogenous matters, by some one of the numerous methods which have been proposed, and a separate estimation of its nitrogen made. The error arising from the somewhat variable compo- sition of • the numerous vegetable albuminoids we have, unfortunately, no means of correcting. In the present state of ouik knowledge, it is impossible to fix upon separate factors, either for the several albuminoids or for different classes of feeding-stuffs, since the same albumin- oid may vary considerably in composition according to its source or mode of preparation, and since the proportions in which these albuminoids are contained in the same vegetable product also vary. Moreover, we have no knowl- edge whatever regarding the composition of the albumin- oids of an important class of feeding-stuffs, the so-called coarse fodders. For the present we are obliged to continue the use of the conventional factor 6.25, bearing always in mind that it is but an approximation to the truth, though probably in most cases a tolerably close approximation. Amides. — For the determination of amides Sachsse's method is generally used. The details of the method are too technical to find a place here ; a description of the two processes proposed by Sachsse may be found in his book, '-''Die Chemie und Physiologie derFarlstoffe, Kohlehydrate 50 MANUAL OF CATTLE-FEEDING. und Protelnsuhstanzeii^'' Leipzig, 1ST7, pp. 256 and 258, and a combination of the two methods, as proposed by E. Schulze, in '^ Die Landwirthschafilichen Yei'suchsSta- tionen^ XX., 117. Cellulose, as ah-eady stated (page 40), is determined by removing other substances, so far as possible, by boiling with dilute acid and alkali, washing with alcohol and ether, and deducting from the weight of the residue the ash and albuminoids which it still contains. The result gives the amount of crude fibre. Fat is determined by dissolving it out of the dried fod- der by extraction with renewed quantities of common (dry) ether, evaporating off the ether fi-om the resulting solution, and weighing the fat remaining after careful drying at 100° C. ^ The ether extract of most grains and the residues from them can be considered as tolerably pure fat, but that of all green and coarse fodders, such as hay, straw, stover, etc., consists of a mixture of the most various substances, among which, along with the real fat, numerous wax and tar- like bodies, and especially leaf -green, or chlorophyll, occur in varying quantity. These substances are certainly of very varying importance, and in part are entirely indigestible. Ash. — The mineral matter, or ash, of a fodder is deter- mined by carefully burning a weighed quantity at as low a temperature as possible, to avoid volatilization of alkaline chlorides. From the ash thus obtained is deducted any particles of coal which it contains, and also the carbonic acid, since the latter is only formed in the burnmg of the organic matter, and is often very variable in quantity, according to the temperature at which the ash is prepared, so that it is not properly a constituent of the latter. MANUAL OF CATTLE- FEEDING. 61 Nitrogen-free Extract. — All that remains of the dry natter of the fodder, after deducting the crude protein, crude fibre, crude fat, and ash, is designated as nitrogen- free extract (JST. fr. Extr.) ; that is, the quantity of the lat- ter is determined by difference. In all grains and roots this is of a tolerably simple na- ture, and consists chiefly of starch or sugar and bodies of the pectin group, and sometimes of vegetable mucilage, which has a composition analogous to that of starch and exerts, probably, an equal nutritive effect. But in green and coarse fodders we have, in addition, varying quantities of gum-like substances and of lignin, which latter partly dissolves when the fodder is treated with acids and alkalies, but, at the same time, appears not to be resorbed in the alimentary canal, and therefore not to contribute to the nourishment of the animal. On the other hand, we shall see further on that all of the nitrogen-free extract which is really digested has the percentage composition of starch, and that, therefore, the non-nitrogenous nutrients of fodders, with the exception of fat, may be considered in general as carbhydrates. The small quantities of organic acids and other bodies present are of no direct importance as nutrients, though they often have an important indirect influence, either by imparting to the fodder an agreeable taste or smell, or the reverse, by some specific physiological action, or by impart- ing undesirable properties to the products of the animal — e. g., the well-known effect of cabbage, rape cake, or onions on milk. Nutritive Ratio. — Along with the composition of a fodder we usually find given its nutritwe ratio, by which we understand the ratio of the digestible protein to the digestible non-nitrogenous nutrients. 52 MANUAL OF CATTLE-FEEDING. From tlie results of large numbers of digestion experi- ments, we are able to tell, with a good degree of certainty, what percentage of the several nutrients of any fodder is digestible, and these results are to be found in tables of " digestion coefficients." Suppose, now, that we have the analysis of a sample of average meadow hay of the following composition : Water 14.3 per cent. Ash 6.2 " Protein 9.7 "• Crude-fibre „ , 26.3 " Nitrogen-free extract 41.0 " Fat 2.5 " 100.0 The average of all available experiments shows that the following proportions of the different nutrients are digest- ible : Protein 56 per cent. Crude-fibre 57 " Nitrogen-free extract 63 " Fat 48 " We therefore multiply the amount of each nutrient con- tained in the fodder by the corresponding digestion co- efficient, and obtain the following results : Digestible protein = 9.7 x 0.56= 5.4 per cent. crude-fibre =26.3x0.57=15.0 extract =41.0x0.63=25.8 " " fat = 2.5 X 0.48= 1.2 " The digestible portions of the crude-fibre and nitrogen- free extract have been shown to have the composition of starch, and may be considered as of equal nutritive value, MANUAL OP CATTLE-FEEDING. 63 poimd for pound ; but the fat produces a greater effect in tlie body than an equal weight of carbhydrates, and this fact must be taken into account. It was formerly believed that the non-nitrogenous nutrients served cliiefly as fuel in the body to maintain the animal heat, and that since a pound of fat yields two and one- half times as much heat when burned as a pound of starch, it was therefore two and one-half times as valuable a food, and hence, in calcu- lating nutritive ratios, the fat was reduced to its " starch equivalent " by multiplication by 2^. We now know that this Is but a partial and, for purposes of feeding, a mis- leading view, and it is probable that in time the present factor, 2|-, will be replaced by a more correct one ; but tliat time is not yet, and, in the meantime, we must follow established custom, for the sake of rendering our analyses comparable with others. We therefore make the following calculation : Digestible fat x 2^ _ = 3.0 Digestible fibre. „ =15.0 Digestible extract =25.8 43.8 Digestible protein » . . . . , . , , , = 5,4 The nutritive ratio, then, is 5.4 : 43.8, or 1 : 8.1 ; the quantity of digestible protein being usually taken aa unity. CRAPTER III. DIGESTION AND RESORPTION. § 1. Digestion. Introductory. — The nutrients described in the preced- ing chapter, as they occur in the ordinary fodders, are not in suitable condition to become at once part of the body. They must be separated from the various useless substan- ces with which they are associated, and be converted into soluble forms, before they can be taken up into the circula- tion and so serve to nourish the body ; — that is, they must be digested. " The digestive apparatus has been compared to the fit- tings of a pharmaceutist's laboratory in which extracts are prepared from organic substances. As, there, the mass to be extracted is pulverized by mortars, rasps, knives, and similar tools, so are the feeding-stuffs by the teeth of the animal ; what is effected there by water, alcohol, ether, and other extracting fluids, the digestive juices which are se- creted by various glands, and with which the whole mass to be digested is saturated, do in the animal body. " As, in the laboratory, the sufficiently extracted materials are filtered to obtain the finished extract, so the filtration of the extracted nutrients in the animal body takes place through the membranes of the intestines. " In the laboratory, the finished extract is received into a suitable vessel, and the worthless residue is thrown away ; in the body, the blood and lymph vessels receive the ex- MANUAL OF CATTLE-FEEDING. 55 tracted nutrients, while the undissolved residue, which has no nutritive value, is removed from the body in the form of the solid excrements. " There exists, however, one great difference between the extracts prepared in the laboratory and those produced in the animal organism ; the former contain, unaltered, the soluble matters which were present in the crude materials, while the constituents of the latter are essentially different fi'om those contained in the food. " This difference is due to the fact that the action of the digestive fluids is a more energetic one, and is accompanied by a chemical alteration of the dissolved substances." — {Set- tegast.) Mastication and Insalivation. — The process of diges- tion takes place in the alimentary canal, consisting of the mouth, gullet, stomach, and small and large intestines. The first step in the process takes place in the mouth, and consists, in the first place, of the act of mastication, by which the food is broken up and thus made to expose more surface to the action of the digestive fluids. At the same time certain glands (salivary glands), opening into the mouth, pour out abundantly a fluid known as the saliva. The secretion of the different salivary glands varies considerably in appearance and properties. The mixed sa- liva, as it is found in the mouth, is a watery, alkaline, somewhat slimy, transparent or slightly turbid fluid, con- taining from one-half to one per cent, of solid matter. This fluid is mixed thoroughly with the food during mas- tication, and serves to moisten and soften it and so to bring it into a suitable condition to be swallowed and further acted upon. Besides moistening the food, however, the saliva con- tains a ferment, called ^tyaUn^ which has the power, at 56 MANUAL OF CATTLE-FEEDING. the temperatur-e of the body, of acting upon starch with very much the same results as boiling dilute acids or alka- lies, viz., converting it into a form of sugar, i. e., a soluble substance which can easily pass into the circulation. To how great an extent this action takes place is a somewhat dis- puted point, but there seems to be little doubt that it is at least of some consequence, though it by no means completes the digestion of the starch, especially in animals having a simple stomach. Moreover, the saliva, being a very watery secretion, dissolves the soluble matters of the food, and forms, to a certain extent, an aqueous extract of it. Rumination. — From the mouth, the food, after being formed into morsels by the tongue, passes through the gullet to the stomach. In animals with a simple stomach, the horse or hog, e. g., the acts of mastication and in- salivation are performed com- pletely at first, but in the case of animals that chew the cud (ruminants), the food is at first only slightly chewed, and then passes into one of the divisions of their compound stomach. The stomach of the ruminants consists of four divisions, as shown in outline in fig. 2. The slightly-chewed masses pass first through the gullet, a, into the largest division of the stomach, the pmmch or first stomach, hh, and partly also into the second stom- ach or reticuluTn, c. Ilere they remain for a time, until softened by the sa- FiO. 2.— (J. Kuhn.) MANUAL OF CATTLE- FEEDING. 57 liva and the alkaline fluid secreted by the stomach itself. What is dissolved here passes directly on through the other divisions of the stomach, while the undissolved sub- stances pass, a portion at a time, into the gullet, and are returned to the mouth to be thoroughly chewed and mixed with saliva. From the opening of the gullet into the fii'st stomach, a passage called the obso^hogean demi-canal leads by the paunch and reticulum to the third stomach. This canal may be described as a continuation of the gullet, having a slit in its lower wall which forms an opening into the fii'st and second stomachs. When the food is swallowed the first time, its bulk seems to open the slit in the canal so that it passes mto these two stomachs as already stated. Wlien swallowed the second time, a portion of it passes through this slit back into the first and second stomachs, but much of it goes on into the third stomach {omasum or manifolds)^ d, from which it does not return again to the mouth. The interior surface of this division of the stomach is composed of numerous folds of mucous membrane, between which the food is received and subjected to more or less mechanical action, while the numerous capillary blood- vessels which the folds contain take up whatever materials are dissolved. From the omasum the food passes to the fourth stomach, abomasum^ or rennet, e, there to undergo the ordinary pro- cesses of digestion in the same manner as in animals with a simple stomach. So long as the young animal lives on milk alone, the first three divisions of the stomach remain undeveloped, and the food passes directly into the fourth ; but as it 58 MANUAL OF CATTLE-FEEDING. begins to eat more voluminous food the fii'st three are de. veloped and begin their fimctions. Liquid foods, in the full-grown animal, pass partly into all four stomachs. The ruminants are thus especially adapted by nature to digest and utilize large volumes of coarse and relatively poor fodder, straw e. g., and to extract from them the nutrients which they contain. The opinion has been almost universally held that a cer- tain volume of fodder is essential to the well-being of rmni- nating animals, and that, when concentrated feeding-stuffs are used, they must be supplemented by a suitable amount of coarse fodder, such as hay or straw, in order that the hn- portant function of rumination may not be disturbed. There is no doubt that a bulky fodder is the natural food of ruminants, but the somewhat famous experiments of Mr. Linus "W. Miller, of Stockton, N. Y., seem to show that rumination may be suspended for a considerable time with no injurious results. Mr. Miller states that for several years he has success- fully wintered his cows on corn-meal exclusively, feeding about three quarts per day and head, and that, although rumination has been entirely suspended for some months, no ill-effects were observed. Several others have also tried his system with favorable results. The question of the sufficiency of such a ration we shall consider further on, but although the experiments have been the object of much criticism they certainly seem to show that a bulky fodder is not so essential to rmninants as has been supposed. Natm-ally, however, coarse fodders will continue to form the basis for the rations of our farm animals under most circumstances ; and since, in that case, the process of diges- MANUAL OF CATTLE-FEEDING. 59 tion is a complicated and a slow one, the animals should be allowed the necessary time and repose to complete the act of rumination undisturbed. Gastric Digestion. — In the fourth stomach of rumi- nants and the simple stomach of other animals, the food is subjected to the action of the gastric juice. This fluid is produced by innumerable small glands, imbedded in the inner coat of the stomach, which, when excited by the pres- ence of solid matter in the latter, pour out abundantly a clear, colorless fluid, having a sour taste and smell, and containing two characteristic ingredients. One of these is inuriatic acid., the chlorine of which comes from the salt of the food ; the other is, pepsin, an or- ganic substance about whose composition and properties little is known with certainty, but which acts powerfully, at the temperature of the body, on the albuminoids of the food. Its first effect on the soluble albuminoids is to coagulate them. Afterward, however, the pepsin, in the presence of the muriatic acid of the gastric juice, acts on the coagulated or the originally solid albuminoids, and converts them into substances called jpejptones, having much the same proper- ties as protein, but soluble in water, and hence easily taken up into the circulation. The formation of peptones from albuminoids seems to be accom- plished by the assimilation by the latter of the elements of water, being similar to the formation of dextrine and sugar from starch by the ac- tion of acids or alkalies. Indeed, albumin, when treated with acids, yields peptones. According to Hoppe-Seyler,* the chief action of pepsin consists in this,, that it unites with the muriatic acid present, transfers it to the "Physiologische Chemie," 1878, p„ 231. 60 MANUAL OF CATTLE-FEEDING. protein, unites with a fresh quantity, transfers this, again, to the pro tein, and so on to an indefinite extent. If this be true, the similarity between the action of the gastric juice and that of acids is very close. The quantity of pepsin concerned in this process is very small, and it is found that the same pepsin is capable of acting over and over again and converting apparently un- limited quantities of albuminoids into peptones, provided that more acid is added from time to time. It is stated that the digestion of the albuminoids by the pepsin and nmriatic acid of the gastric juice, and their conversion into soluble peptones, is facilitated by the pres- ence of a little fat in the food, and by salt, which causes an increased secretion of the gastric juice. It is hindered by dilution of the gastric juice by large amounts of drink, and too high or too low a temperature of the drink may, by destroying the pepsin, suspend the digestion altogether, until new pepsin can be secreted. The action of the gastric juice on the food is aided by a peculiar action of the involuntary muscles which form one of the coats of the stomach. These keep the food con- tinually in motion in the stomach, and in this way mix it thoroughly with the gastric juice, so that all parts of it may be acted upon. By means of the gastric juice, aided by the motion of the stomach just described, portions of the food are dissolved, and the whole converted into a more or less fluid mass called chyme. A portion of the chyme is resorbed in the stomach, and passes directly or indirectly into the circulation. Tliis is the case with the sugar produced fi'om the carbhydrates of the food by the saliva, with the vegetable acids, and in general with the easily soluble constituents c>f the chyme, MANUAL OF CATTLE-FEEDING. 61 and witli water. They are largely (not entirely) taken up by the blood-vessels of the stomach. Some of the pep- tones are also resorbed in the stomach, though not into the blood-vessels but into the lymphatics, but a large part of them, along with the portions of the food not yet acted on, leaves the stomach through a valve, called the ;pylor\ts^ at its lower end (/J fig. 2), and passes into the intestines (^, %• 2). Intestinal Digestion. — The intestines form a long tube, folded and bent many times upon itself, which, togetlier with the stomach, liver, and a few other organs, fills the cavity of the abdomeUo Its length varies very considerably in different animals. In carnivorous animals, which live on easily-digested and concentrated food, it is from four to six times the length of the body ; while in herbivorous animals, which feed on vo- luminous fodder, it is very much longer, being ten to twelve times the length of the body in the liorse, twenty times in the ox, and twenty -five to twenty-six times in the goat. It is divided into two principal parts — the small intestine, be- ginning with the stomach and forming about f to f of the whole length, and the large intestine, ending with the anus. The movement of the food through the intestines is accomplished by a peculiar worm-like motion of the latter, resembling that of the stomach and called the peristaltic motion. It is produced by the involuntary muscles of the intestines, and effects both a forward movement of the food and a mixture of it'with the various digestive fluids to whose action it is subjected. Chief among these digestive fluids are the bile and the pancreatic juice. The hile, or gall, of the herbivora is a dark yellowish- green li(_[uid, secreted by the liver, the largest gland m the 62 MANUAL OF CATTLE-FEEDING. body, and, in most animals, stored up in the gall-bladdel till it is needed. The composition of the bile is very complex, and need not be taken up in detail here. It contains two character- istic coloring matters, hiliruhin and hiliverdln^ but its most important and necessary ingredients are compounds of soda with certain organic acids, viz. : glycocholic and taurocholic, and in the hog hyoglycochoUc acids. The soda of these compomids comes almost entirely from the salt (sodium chloride) of the food, while the same substance furnishes chlorine for the equally necessary muriatic acid of the gastric juice. The chief action of the bile is on the fat of the food, A small portion seems to be decomposed by the soda salts of the bile, forming soluble soda salts of the fatty acids (soaps) ; but the main effect is to emulsify the fat, that is, to separate it into minute globules like the butter globules in milk, and to hold these globules suspended, so that the whole forms a thin fluid resembling milk and called an emulsion. This fluid can be taken up by the resorbent vessels of the intestines when the latter are wet with bile. Besides its function of digesting the fats, the bile serves to hinder, to some extent, the decay of the easily decom- posable albuminoids. When bile is added to the contents of the stomach in the state in which they enter the intestines, the peptones which they contain, as well as the pepsin, are precipitated and the digestive process is stopped. A further addition of bile, however, redissolves the precipitate, but since the muriatic acid of the gastric juice is neutralized by the soda of the bile, the action of the pepsin is stopped. In the in- testines, however, the latter is more than replaced by the ferment of the pancreatic juice. MANUAL OF CATTLE-FEEDING. 63 The bile is secreted in very considerable quantity, but most of what is not used in digestion is taken up by the blood-vessels and resorbents of the intestines. The color of the solid excrements is due largely to portions of the bile that escape resorption. The jpancreatic jidce, the secretion of the pancreas, or sweetbread, is a clear, viscid, colorless liquid, having a slightly salt taste and a distinctly alkaline reaction. It contains at least three distinct ferments, viz. : a dias- tase, capable of converting starch into sugar ; tryj^sin, which acts on the albummoids ; and a ferment which sepa- rates fats into glycerine and fatty acids. By virtue of the first of these ferments, the starch of the food which is not acted on in the stomach is rapidly converted into su2:ar. The trypsin of the pancreatic juice acts powerfully upon albuminoids in much the same way as the pepsin of the gastric juice, but with the differences that trypsin acts in alkaline or at most very weakly acid Golution, and that the decomposition goes further. Under the action of pepsin the albuminoids yield chiefly peptones, wdth small quantities of the well-known amides, leucin and tyrosin, while trypsin, on the contrary, decom- poses the peptones at first formed, and produces abundant quantities of the amides just mentioned, at least in artifi- cial digestion experiments. The action of the pancreatic juice upon the fats is a two-fold one ; it rapidly converts them into an exceedingly fine and permanent emulsion, and more slowly decom- poses them into their constituents, glycerine and fatty acids. It will thus be seen that the pancreatic juice is a most important secretion, acting, as it does, upon all three 64 MANUAL OF CATTLE-FEEDIXG. classes of nutrients and supplementing the saliva, the gastric juice, and the bile. Intestinal fluid. — It is commonly stated that, in addi- tion to the bile and pancreatic juice, the food is acted on by a third fluid secreted by numerous little glands, known as Lieberkiihn's glands, in the nmcous membrane of the intestines. The statements regarding the composition of this fluid and its action on the food are very conflicting, doubtless owing in part to the difiiculty of obtaining it un- mLxed with the other digestive fluids, and there seems to be considerable doubt of its existence, which at any rate cannot be regarded as proven. Recapitulation. — We see, then, that the whole process of digestion is simply a conversion of the solid matters of the food into forms which are soluble in water or in the digestive fluids and can therefore pass into the circulation. This is accomplished, in case of the albuminoids by the gas- tric juice in the stomach and the pancreatic juice in the intestines, in case of starch, etc., by the saliva and the pan- creatic juice, and in case of the fats by the bile and pan- creatic juice. In what part of the alimentary canal, or by what secretion, cellulose is digested, is not known. Possi- bly the pancreatic juice, which acts so powerfully on the other carbhydrates, is the agent of its solution, but this is only a conjecture. . The latest view regarding the digestion of cellulose is that it is not accomplished by any specific digestive fluid, but that in the extensive digestive canal of the herbivora it undergoes a sort of fermentation, caused by the innu- merable bactei'ia and other low organisms there present, and yields marsh gas, carbonic acid, hydrogen, and various soluble products. By the action of these various digestive fluids, the chyme MANUAL OF CATTLE-FEEDING. 65 which comes from the stomach is converted into a more or less thin, milky fluid, called chyle. The ease of digestion depends on various circum- stances. Digestion is both a chemical and physical process, con- sisting of solution and chemical change of the nutrients by means of the digestive fluids, and the rapidity of this pro- cess depends, in general, upon the same conditions which determine that of similar processes outside the body. Hard and compact fodder is less easily digested than that which is soft and watery, other things being equal, simply be- cause it is not so easily penetrated by the juices, and hence exposes less surface to their action, just as coarse salt dis- solves more slowly than fine. If the nutrients are shut up in insoluble envelopes, they are protected from the action of the juices. Thus, if we have starch in a cell whose walls are incrusted thickly with the indigestible (because insoluble) lignin, the starch may be, to a large extent, protected and escape digestion. So, too, if whole grain is fed and escapes mastication, the hard outer coats of the seed protect the interior, and the grain is frequently found with little alteration in the ex- crements. In a chemical process, the proportions of the substances concerned are of the greatest importance. So, too, in digestion, the proportions of albuminoids, carbhydrates, and fat, exercise an important influence on the digestibility of each of these groups, though exactly in what way we are ignorant. That a moderate proportion of fat aids the digestion of the albuminoids in the stomach, has already been men- tioned. Too great an amount of fat, on the contrary, hinders digestion. 66 MANUAL OF CATTLE-FEEDING. If the fodder be poor in albuminoids and rich in starch, the latter may escape digestion in considerable quantities ; and as it is of no value in the manure (since it only fm*- nishes to the plant the elements of carbonic acid and water, with both of which it is richly supplied by the atmosphere) that which thus escapes is a dead loss, while if, on account of a too great proportion of albuminoids, a portion of these pass into the manure, they still are able to furnish the plant with the valuable element, nitrogen. In a properly proportioned fodder, however, the quan- tity of really digestible matters that escapes digestion is comparatively small, although ^ij^erfect digestion of them is not to be expected. Small portions will escape diges- tion, either owing to their hardness and impermeability, or to their being protected by insoluble matters, or simply from the fact that they are not exposed for a sufficient time to the action of the digestive fluids. This is shown by the fact that the ruminants, in which the process of digestion is long, extending through two or three days, are able to digest more of hard and diffi- cultly soluble matters, especially of crude fibre, than other herbivora, in which the process is simpler and shorter, the horse, e. g. § 2. Resorption. We have seen that the process of digestion is essentially a process of solution, the various nutrients of the food be- ing altered into soluble forms and dissolved by the diges- tive fluids. But the digested food, so long as it remains in the ali- mentary canal, is, to a certain extent, still outside the body ; it has not yet been taken up into its vessels and be- come really a part of it. It must still be resorhed or taken MANUAL OF CATTLE-FEEDING. 67 up into the circulation by the resorbent vessels which line the stomach and intestines. The Epithelium. — In all vertebrate animals, the whole surface of the intestines, from end to end, is covered with so-called epithelial cells, which are remarkably similar in all animals. These cells are roughly cylindiical, and are thickly crowded together, leaving no spaces between them. They are separated from each other by a cell wall, but are open toward the interior of the intestines, and also, ac- cording to some authorities, communicate on the other side with the lacteals. The cells contain a soft mass of protoplasm, which, when resorption is not going on, bears on its intestinal sm-face minute upright fibres, which give the surface of the intes- tines a velvety appearance. During resorption, however, these fibres nearly disappear into the main part of the cell contents. The Villi. — In the higher animals the extent of resorb- ing surface in the intestines is greatly increased by various folds and projections of its surface, of which the most important are the villi. These are little conical, round, or club-shaped protuberances of the inner surface of the in- testines. They are covered, like all parts of the intestinal surface, with the epithelial cells just described, and under- neath these there is said to be a fine membrane. Beneath this membrane there are found numerous minute capillary blood-vessels, a layer of smooth (involuntary) muscular fibres, and a net-work of nerves. All three layers fol- low the epithelium of the intestines in all its folds and projections, and thus in the villi take somewhat the shape of a glove-finger. In the centre of each of the viUi ends a vessel called a lacteal, belonging to the lymphatic system. 6S MAiq-UAL OF CATTLE-FEEDING. Fig. 3 sliows a longitudinal section of a villus, in which a represents the epithelial cells, h the capillary blood-ves- sels, c the layer of muscular fibres, and d the lacteal. Lacteals and Blood-Vessels. — The lacteal s unite into larger ones leading to the mesenteric glands^ and after leaving these, finally join the thoracic duct, a large vessel leading forward (in man upward) and emptying into a vein in the left side near the collar-bone, called the left suhclavian vein, near its entrance into the heart. They derive their name from a millvy- looking fluid with which they are filled during digestion, and which owes its ap- pearance to the digested and emulsified fat of the food which has been resorbed from the chyle. At other times they contain a clear or opalescent liquid called lymph. The capillaries of the intestines also unite into larger vessels, and finally into one, the ])ortal vein, leading to the liver. (Compare fig. 4, p. 77.) There the blood which it carries is distributed through a second set of capillaries in that organ, and then reunited again into a single vein, the he2)atic vein, leading almost directly to the heart. Phenomena of Resorption. — As soon as the food passes from the stomach into the intestines, the resorbents of the latter begin their work, and the two processes of digestion and resorption go on simultaneously. Our knowledge of the processes of resorption is not as full as might be wished. We know that liquids and soluble Bubstances brought into the intestines, rapidly disappear MANUAL OF CATTLE-FEEDIKG. 69 from them. In some cases tlie substances thus resorbed are excreted unchanged ; in others we are able to recognize the products of their decomposition without being able to say exactly where they are destroyed. Water introduced into the intestine disappears, and is excreted unchanged in the urine and perspiration ; sugar, on the other hand, while it is rapidly resorbed, does not reappear as such, but speedily causes an increased excretion of carbonic acid through the lungs, showing that it has been oxidized in the body. It would seem that only soluble substances are resorbed, both from the fact that solutions are readily taken up and that the whole digestive process is di- rected toward solution of the solid ingredients of the food. The fats, however, form to a certain extent an exception. We have seen that in the digestive process they are simply emulsified, and only to a very small extent dissolved. After a meal containing much fat, the lacteal s are found to be full of a fluid having a milky appearance which the microscope shows to be due to the presence of innumerable globules of fat, which have evidently been resorbed from the contents of the intestines, having passed through the epithelial cells. Causes of Resorption. — It has been extensively taught that the phenomena of resorption are due chiefly to the action of the laws of the diffusion of liquids through mem- branes, aided by the pressure exerted on the contents of the intestines by the peristaltic motion. It is well known that, if solutions of many substances be enclosed in some membrane, like bladder or parchment- paper, and the whole placed in water, tlie dissolved sub- stance will diffuse through the membrane into the water until the solution is of equal strength on both sides of the membrane, and that, if the water be continually renewed, 70 MANUAL OF CATTLE-FEEDING. all the dissolved matter will finally be removed from the solution contained in the membrane. Substances which are capable of thus passing through a membrane are said to be diffusible. In the body, according to this theory of resorption, the intestines constituted the enclosing membrane, the diges- tive fluids converted the nutrients into soluble and diffusi- ble forms, while the blood and lymph of the capillaries and lacteals was the fluid into which diffusion took place. It was found that emulsified fats could, by slight pressure, be made to pass through a membrane previously moistened with bile, and on this fact was based the explanation of the resorption of fat, the pressure being supposed to be exerted by the peristaltic movements of the intestines, and the pro- cess of filtration to be aided by a peculiar structure of the villi which kept the lacteals in their centre under a less pressure than was exerted on the outside. In short, re- sorption was believed to consist in diffusion, combined with filtration imder pressure. This theory has been extensively held, but the best au- thorities now consider it entirely inadequate to explain the known facts of resorption. As regards the resorption of fat, the simple fact that the villi are wanting in many of the lower animals, and that these animals nevertheless resorb fat, shows that the sup- posed peculiar structure of the villi is not essential to the process, and a more careful consideration of the anatomy of the intestinal surface shows that the filtration theory is untenable. The whole of this sm-face is covered with the epithelial cells above described, so closely crowded together that any filtration must take place tlirough the semi-fluid proto- plasm of the cells. This protoplasm must behave midei MANUAL OF CATTLE-FEEDING. 71 pressure essentially like a liquid, that is, it must exert an equal pressure upon all sides of an object enclosed in it; under these circumstances, while diffusion may take place, filtration is impossible. But if we admit the impossi bility of filtration, the whole theory falls, for diffusion alone would, in many cases, produce results entirely dif- ferent fi-om those observed. For example, if water and alcohol be separated by a membrane having a greater at- traction for water, the water passes through the mem- brane toward the alcohol faster than the latter passes in the opposite direction, but if alcohol, so diluted as not to injure the epithelium, be introduced into the intestines, it is rapidly resorbed into the blood, while no water passes from the latter into the intestines. Moreover, while under normal conditions water is rapidly resorbed, simple irritation of the epithelial cells is suffi- cient to cause the motion to take place m the opposite direction, viz., from the blood into the intestines. These and many other considerations force us to the belief that the epithelium of the intestines is the active agent in resorption, and that resorjjtion is a function qf the living protoplasm of the epithelial cells. In what manner, or by virtue of what chemical and physical laws, the process takes place, we are ignorant ; and until the relations and properties of protoplasm in general are much better known than at present, it must be regarded as a vain attempt to seek to discover them, nor, indeed, is it important for our present purpose that we should. Course of the Nutrients after Resorption. — The substances taken up by the epithelial cells appear to pass from these into the lacteals. Their course from this point is not, in all cases, easily followed, on accoujit of the rapid alteration which they midergo. 72 MANUAL OF CATTLE-FEEDING. The fat seems to be carried exclusively by the lacteals, and to pass through the mesenteric glands and thoracic duct into the left subclavian vein, as already described. Other substances pass more or less completely into the blood. It will be remembered that the lacteals in the villi are surrounded by a net of capillary blood-vessels through which blood is continually passing, and there appears to be no reason why the easily diffusible substances of the lymph should not pass into the blood, especially since the latter, being continually renewed, would act like a large volume of fluid. Probably, then, the products of the digestion of the carbhydrates — viz , sugar, lactic acid, etc. — pass, in large part, into the blood and through the portal vein, the capil- laries of the liver, and the hepatic vein, to the heart. The same would be true of the amides formed by the action of the pancreatic juice and by decay from the albuminoids, and to a less degree of the peptones, while unaltered pi"o- tein, if resorbed, would be largely retained in the contents of the lacteals, owing to its slow rate of diffusion. All these statements are, however, to a certain extent, speculative. It is highly probable that the resorbed mat- ters undergo chemical change in the act of resoi-ption by the epithelial cells : at any rate they undergo such rapid alteration after resorption that only traces of most of them can be observed either in the lymph or in the blood of the portal vein. The Faeces. — By the process of resorption the chyle, as it moves along through the intestines, is exhausted of its soluble parts and takes on a more and more solid con- sistency, and finally is voided fi'om the body as the faices. The solid excrements consist of the indigestible part of the food, those digestible parts which for any reason may MANUAL OF CATTLE-FEEDING. 73 have escaped resorption, and small portions of tlie diges- tive fluids and of the worn-out mucous membrane of the in- testines. In the herbivora they also generally contain all the phosphoric acid coming from the metamorphosis of the tissues of the body, while in the carnivora this substance is excreted in the urine. The color of the excrements, as already mentioned, is usually due to the portions of the bile which have escaped resorption ; when much green fodder is eaten, its green coloring-matter (chlorophyl) passes unaltered into the faeces. The composition of the solid excrements varies largely according to the feeding of the animal. It is seldom possible to attain a com2>lete digestion of all the nutrients of the food ; a certain portion almost always escapes digestion, unless, perhaps, in the concentrated bye- fodders. The undigested portion is generally larger when a rich food is given, i. e.^ when we strive for a rapid production of organic substance, whether flesh, fat, or milk, than when the fodder is just sufficient to maintain the animal. In the former case, too, the residues of digestive fluid and of worn-out intestinal membrane are greater, owing to the greater activity of these organs and the greater quantity of juices necessary to digest the richer and more abundant fodder, so that fi'om fattening or milk cattle we get not only a utilization of fodder materials and conver- sion of them into valuable products, but an increase in the manurial value of the solid excrements, while in the case of animals on maintenance-fodder the mamu'e is the only return for the fodder, and is of poorer quality than when richer food is given. CHAPTER IV, CIRCULATION, RESPIRATION, AND EXCRETION. § 1. Circulation. The Blood. — We have seen, in the precedmg chapter, that the digested and resorbed nutrients of the food are carried more or less dii'ectlj into the blood, and it is fi'om this fluid that all parts of the body derive those substances necessaiy for their growth and the performance of their functions. The blood of the higher animals is a thickish, somewhat viscid fluid, ha\4ng a faint but peculiar odor, a slightly salt taste, and a color varying from bright to a dark red. It is somewhat heavier than w^ater (sp. gr. 1.0i5 — 1.075), and contains about 21 per cent, of solid matters. Under the microscope it is seen to consist of a clear fluid, the jdas?na, holding in suspension a vast number of small, round disks, the cmpuscles. The corjntscles are of two kinds. By far the most nu- merous are the red corpuscles. In man these are round like a coin but thicker at the edges than in the centre, and have a diameter of .0060 — .0085 millimetres. Their number is enormous, being estimated at 1— 5J millions per cubic millimetre. The color and opacity of the blood are due to the corpuscles. The corpuscles of each kind of animal are peculiar, both in shape and size, but their general characteristics are the MANUAL OF CATTLE-FEEDING. 75 same in all. Those of most mammals are smaller than those of man. The corpuscles contain, as characteristic ingredients, two coloring-matters, known as hcemoglohin and oxyhoernoglo- hin^ of each of which there appear to be several varieties in the blood of different animals. Ai'terial blood contains only oxyhgemoglobin. This sub- stance is a bright red, crystalline body, having pretty nearly the percentage composition of protein, but contain- ing about 0.45 per cent, of iron. Its most remarkable property, however, is the readiness with which it parts with a portion of its oxygen and is converted into haemoglobin. In the body this process takes place in the capillary blood-vessels, so that the blood as it returns from these to the heart (the venous blood) contains both oxyhsemo- globin and haemoglobin. The latter is capable of the reverse change, and in the lungs takes up oxygen and is converted back into oxyhsemoglobin. Besides these two coloring-matters, the corpuscles con- tain an albuminoid which is precipitated by concentrated salt solution, small quantities of two bodies known as cho~ lesterin and lecithin^ some other organic matters, and the usual ash ingredients, potash and phosphoric acid being especially abundant. In addition to the red coi*puscles the blood contains colorless corpuscles, differing in shape and appearance from the red and generally larger. They appear to be formed in the lymph before it joins the blood, but their exact function is not well ascertained. Their number is vastly less than that of the red, there being about one or two of the former to a thousand of the latter. The plasma is a nearly transparent fluid, containing in solution a large part of the nutritive matters of the blood. 76 MANUAL OF CATTLE-FEEDING, Of the albuminoids, it contains albumin, and blood-fibrin or at least one constituent of it ; it also contains some fat, usually traces of sugar though never large quantities of it, and a considerable proportion of mineral matters, espe- cially of soda salts and chlorides, besides minute traces of various other substances. Coagulation. — So long as the blood remains in the ves- sels of the living body it continues fluid, even if its circu- lation be stopped, but when drawn from the body it co- agulates after standing for a time, yielding a yellowish liquid, the serum, and blood-fibrin. At ordinary temper- atures the change takes place rapidly, but only slowly at a low temperature ; it is entirely hindered by addition to the blood of a strong solution of sulphate of soda, sulphate of magnesia, nitrate of soda, common salt, and other sub- stances. Opinions differ as to the nature of the coagula- tion, but it is certain that the blood-fibrin does not exist as such in the blood but is formed from a substance called fibrinogen, contained in the plasma, and concerning which three facts may be considered as established : 1st. Fibrin is only formed in fluids which contain fibrinogen. 2d. A solution of fibrinogen alone yields no fibrin, and hence the action of some other body or bodies is requisite. 3d. This other body or bodies is yielded by the colorless corpuscles. A. Schmidt, who has most fully investigated this sub- ject, regards the substances coming from the colorless cor- puscles as partaking of the nature of a ferment, and be- lieves that they are not contained in the living blood but are formed, after the blood is drawn from the body, by the decomposition of the corpuscles. Whether this be true or not, there is no doubt that these corpuscles yield a sub- stance capable of converting fibrinogen into fibrin. Fig 4. — rian of Circulation. MANUAL OF CATTLE- FEEDING. 77 The Heart. — The movement of the blood through the body, in order that all organs may receive from it their necessary nourishment, is accomplished by the heart. The heart is an irregularly conical-shaped organ, com- posed of involuntary muscles. It is situated in the ante- rior part of the chest, and hangs free in an envelope called the jpericardiuTYi. It is divided by an impervious partition into a right and left half, and each of these is subdivided by a cross-par- tition into two chambers, communicating with each other by a valve in the dividing wall. The upper and smaller of these divisions are known as the right and left auricles^ and the lower and larger as the right and left ventricles. Into these divisions open several large blood-vessels, whose mouths are closed with valves so arranged that the blood can only flow i7ito the auricles and out of the ventricles. The blood returning from the extremities of the body to the heart enters first the right auricle, a (Fig. 4), through two large veins, the vena cava anterior^ k, coming from the anterior, and the vena cava j}Osterior, I, from the posterior part of the body. The auricle then contracts, and the blood, being prevented from returning into the blood-vessels by the valves at their mouths, is forced through the valve in the partition wall into the right ven- tricle, h. This, in its turn, contracts, and the blood, pre- vented as before by a valve from turning back in its course, is pressed out of the ventricle through the pul- monary artery, c, which divides into two branches leading to the right and left lungs, d, d. The opening of this blood-vessel, like that of the others, is provided with a valve, which prevents the return of the blood. The blood, after having been purified in the lungs, returns to the Ift auricle,^, through the pulmonary veins, represented by e. 78 MANUAL OF CATTLE-FEEDING. Tlie auricle then contracting, sends the blood into the left ventricle, ^, which, in its turn, contracts powerfully and expels the blood into one large vessel, the aorta^ h. The aorta, soon after leaving the heart, divides into two branches, the anterior aorta, i, leading to the fore part of the body, and the jposterior aorta, j, supplying the abdom- inal cavity and the posterior part of the body. These blood-vessels repeatedly subdivide and carry the blood to all parts of the body, to be brought back again to the right side of the heart and undergo the same process anew. The sole cause of the motion of the blood is tlie power- ful contraction of the muscles of the heart. This alter- nate contraction and relaxation constitutes the beating of the heart, and the sudden impulse thus given to the blood in the arteries causes the beating of the pulse. The Arteries, which conduct the blood from the lieai't to the various organs of the body, are tubes with strong, elastic, and contractile walls, to withstand the force with which the blood is pressed into them by the heart. They originate in the aorta, h (Fig. 4), which receives the blood from the left ventricle, and as they extend farther and farther from the heart throw off brandies to the vari- ous organs, become smaller and smaller, and finally end in the cajyillaries. The Capillaries are exceedingly fine blood-vessels which penetrate all parts of the body and form the con- necting link between the arteries and veins. Their walls are thin and delicate, and through them the nutritive mat- ters of the blood diffuse out into the tissues to repair their w^aste, while the worn-out matters, at the same time, dif- fuse into the blood. Thus all parts of the body are kept continually bathed in a solution of nutritive matters. In the capillaries, too, the oxygen which the blood has MANUAL OF CATTLE-FEEDING. 79 taken up in the lungs unites with some of the worn-out matters and burns them, producing the animal heat. This point will be spoken of 6 more fully in the next section. In Fig. 4, n represents the capillaries of the posterior part of the body, o those of the stomach and intestines, t those of the kidneys, j> those of the liver, and m those of the an- terior part of the body. The capillaries gradually unite together into larger ^^«- ^-csettegast.) capiiianes. vessels, the veins, which convey the blood, no longer suited to nourish the body, back to the heart and lungs. The Veins are tubular vessels somewhat similar to the arteries, but with weaker and non-elastic walls, the pres- sure of the blood on them being less, owing to the inter- position of the capillaries between them and the arteries and to the fact that they are larger than the latter. To prevent any possible flowing back of the blood, the veins are provided at intervals with valves which permit the blood to pass toward the heart but not in the opposite direction. The smaller veins unite to larger ones, and finally, as already described, empty their contents through two branches into the right auricle of the heart. From the capillaries of the intestines the blood carrying the re- sorbed nutrients passes through the portal vehi^ s, to the liver, J?, there passes through another system of capillaries, and then rejoins the blood from the extremities through tlie hepatic vein, u. Into the branch, l\ coming from the head so MANUAL OF CATTLE-FEEDING. and anterior part of the l)ody, the nutrients which are resorb ed by the lacteals are poured just before it enters the heart. The passage of the blood from the left heart through the body and back to the right heart, is called the greater or systemic circulation ; that from the right heart through the lungs to the left heart the pulnionary circulation. The appearance of the blood in the veins and arteries is strikingly different. In the veins it has a dark, cheriy- red color, but after it has passed through the lungs and is sent out by the heart into the arteries it has a bright, scarlet color. The former is called venous, the latter arte- rial blood. An exception to this rule, that the arteries carry bright-red blood and the veins dark, is found in the pulmonary circulation, where, of course, the vessels leadhig from the right heart to the lungs carry venous blood, and those leading from the lungs to the left heart, arterial. Nevertheless, the general nomenclature is adliered to, and the former are called arteries and the latter veins. Arteries conduct the blood from the heart, veins toward it. § 2. Respiration. Under respiration we liere include not only the act of breathing, but all those chemical changes in the body of which that act is partly the cause and partly the consequence. The Lungs. — The principal organs of respiration are the lungs, which, with the heart, occupy the cavity of the chest. This cavity is enclosed on the sides by the ribs, and is separated from the abdominal cavity, containing the digestive organs, by a strong, arched, muscular partition, the dla2>hragm. The diaphragm is convex toward the chest, and by its contraction and a simultaneous outward motion of the ril)s, caused l)y muscles situated between them, the size of the chest cavity is enlarged, and air MANUAL Ot" CATTLE-i^KEDtNG. 81 ruslies into the lungs by virtue of the atmospheric pres- sure. This constitutes the movement of inspiration, or breathing in. The reverse motion, which immediately follows and expels a portion of the air, constitutes the movement of expiration, or breathing out. The air enters the lungs through the trachea, or wind- pipe, from the mouth and nostrils. The trachea, after reaching the chest, divides into two branches, one leading to the right and the other to the left lung, and each branch subdivides asrain and a2;ain into a multitude of fine tubes, called bronchial tubes, each of which finally ends in an ulti- mate lohule, consisting of sev- eral minute vesicles. In Fig. 6, G represents the nltimate bronchial tube, h h the vesicles, and the whole mass of vesicles constitutes an ultimate lobule, a. The vesicles and tubes have elastic walls and are surrounded by an elastic tissue, so that the whole lung constitutes a spongy mass which expands or con- tracts with the motions of the chest, causing the air to flow into and out of all parts of it. The vesicles are also surrounded by a net-work of ex- tremely fine capillary blood-vessels, through which the blood sent to the lungs by the contraction of the right ventricle of the heart must pass, and the walls both of the capillaries and of the vesicles are very thin and are permeable to gases. Exchange of Gases in the Lungs. — The venous blood, as it comes to the lungs, is rich in carbonic acid, Fig. 0. — (Frey.) Lung Tissue. 82 MANUAL OF CATTLE-FEEDING. derived from tlie burning of waste products in tlie capil« laries, and for the same reason is poor in oxygen ; while the air in the vesicles of the lungs, on the contrary, is rich in oxygen and contains but little carbonic acid. Under these circumstances each gas moves from the place where it is most abundant to the place where there is a deficiency of it. The carbonic acid of the blood diffuses througli the membrane of the blood-vessels into the air of the vesicles till the latter is as rich in that gas as the former, while the oxy- gen, at the same time, passes from the vesicles to the blood. The carbonic acid is largely contained in the plasma of the blood, and simply diffuses into the air in the lung vesicles and is expelled in expiration, but for the taking up of oxygen there is a special provision in the coloring matters of the coi'puscles. The venous blood contains both hsemoglobin and oxyhsemoglobin. AVhen the blood passes through the lungs the haemoglobin unites with the oxygen which dift\ises into it, and when the aeration is properly performed is all converted into oxyhaemoglobin, which gives the arterial blood its bright-red color. The corpuscles thus act as vehicles for conveying oxygen from the lungs to the remotest regions of the body. In the capillaries this oxygen is given up again in part, and haemoglobin formed once more, giving to the venous blood its dark-red color. If by any means respiration is stopped, the air in the lung vesicles speedily becomes so charged with carbonic acid and exhausted of oxygen that the exchange of gases with the blood can no longer go on ; the carbonic acid is re- tained in the latter, the waste products of the tissues are not burned, and the animal's blood is poisoned — it is suffocated. If its supply of air, however plentiful, contains more than a certain amount of carbonic acid, the removal of this MANUAL OF CATTLE-FEEDINa. 83 gas from the blood is made incomplete or suspended en- tirely, and substantially the same results ensue, though more slowly. Respiration through the Skin. — In addition to the exchange of gases between the air and the blood which goes on in the lungs, a similar process takes place, though to a smaller extent, through the skin. The true skin, underlying the cuticle or scarf-skin, is penetrated by capillary blood-vessels, and in its passage through these capillaries the blood gives off some carbonic acid and takes up some oxygen by diffusion through the skin. The amounts thus given off and taken up are small compared with the corresponding amounts in the lungs, but they are still not inconsiderable. The skin likewise acts, by means of its sweat-glands, as a channel for the re- moval of water from the system. Large amounts of water are continually evaporating from the skin in the form of the " insensible perspiration," while under certain circum- stances the excretion of water is so rapid as to give rise to the formation of visible drops. The distribution of oxygen through the body is accomplished by means of the circulation. Each little cor- puscle carries its load of oxygeft fi'oni the lungs through the heart and arteries into the capillaries. There, as we have seen, the substances formed in the minute cells of the tissue by the decomposition of their contents under the influence of the vital force, diffuse into the blood, and here they meet the oxygen con- tained in the corpuscles and unite with it — are burned, producing the aniinal heat. Innumerable intermediate products are formed in this process, but the final result is in all cases the same. All the non-nitrogenous sub- stances yield carbonic acid and water; the nitrogenous 84 MANUAL OF CATTLE-FEEDING. ones the same substances, and in addition urea, the char- acteristic ingredient of the urine. Urea is a crystallizable body of comparatively simple composition, which, together with small amounts of other substances, contains all the nitrogen and part of the carbon and hydrogen of the albuminoids from which it is derived. In the urine of herbivorous animals it is, in part, replaced by Id^uric acid. All these oxidations take place in the cells and capillaries of the body, and it is there, consequently, and not, as is sometimes stated, in the lungs, that the animal heat is produced. The quantity of oxygen which passes into the blood is by no means determined by the depth and fre- quency of the inspirations, but by the amount needed in the hody ; that is, in the first place, by the rapidity of the decomposition of substances in the blood and tissues, as well as, m the second place, by the nmnber and quality of the blood coi-puscles. In all parts of the living body a continual decomposi- tion of its materials is going on, and all manifestations of life are intimately related to this metamorphosis of the materials of the living organism. This decomposition, as has been already pointed out, consists, in the main, in a splitting up of complex com- pounds into simpler ones, accompanied by a Liberation of energy, which manifests itself in various ways. The processes take place according to fixed laws and at first in- dependently of oxygen, but the products of the decomposi- tion unite with the oxygen of the blood and regulate the amount of this substance taken up in respiration. The splitting up of substances in the body to form simpler compounds must be regarded as the primary process and the taking up of oxygen as the secondary, although it was MANUAL OF CATTLE-FEEBING. 85 formerly believed that, inversely, the former was deter- mined by the latter. K, by an increased supply of food or by violent muscular exertion, this splitting up of the materials of the body is increased and facilitated, then, secondarily, more oxygen will be taken up, ui order that the resulting products may be oxidized. Storing up of Oxygen. — We have hitherto, for con- venience, spoken as if the oxygen taken up by the blood united at once in the capillaries with the products of tis- sue change. Numerous experiments by Pettenkofer and Yoit,* at Munich, and by Henneberg,f at the Weende Experiment Station, have, however, shown that the animal body has the power of storing up within itself a considerable amount of oxygen, and that some time may elapse after oxygen is taken up into the blood before it is excreted in combina- tion with carbon and hydrogen. The following experi- ment by Pettenkofer and Yoit, upon a healthy man on an average diet, will serve to illustrate the point. The ex- periment was divided into two parts, the time from 6 a.m. to 6 P.M. being designated as day and from 6 p.m. to 6 A.M. as night. If fi-om the amount of carbon, hydrogen, oxygen, and nitrogen, contained in the food eaten, we sul)tract the amounts excreted in organic combination in the solid and liquid excrements, and also the amounts laid up in the body in the form of fat, etc., the remainders will show how much of each element must have been burned to car- bonic acid and water in the body. This known, we can easily calculate the amount of oxygen necessary for the process, and compare it with the amount actually taken up * Zeit. f. Biologie, II., 552. f Neue Beitrage, etc., 1871, p. 245. 86 MANUAL OF CATTLE-FEEDING. from the air, as determined by the metliod described in a subsequent chapter. In this experiment the following results were obtained : DAY. In food. In excreta. In fat formed in body. Remain to be oxidized. Oxygen required. 240.15 195.40 1455.79 10.12 7.94 1.71 8.64 10.12 86.91 13.53 13.10 0.00 145.30 180.16 1434.05 0.00 387.46 1441.28 Oxvcren Nitrogen 1828.74 Already present 1434.05 Needed from without 394.69 Actually taken up from air 234. 70 Difference —159.99 NIGHT. In food. In excreta. In fat lost by body. Remain to be oxidized. Oxygen required. Carbon 75.35 75.50 548.11 7.24 19.16 3.19 12.26 7.24 47.11 7.33 7.10 0.00 103.30 79.64 542.95 0.00 275.50 Hvdrosren 637.12 Oxvsren Nitrogen Already present Needed from without Actually taken up from air. 912.62 542.95 369.67 474.30 Difference , +104.63 Difference for 24 hours — 55.36 MANUAL OF CATTLE-FEEDING. 87 Fn the night-half of the experiment, there was taken in- U- the system through the hmgs 104.63 grms. of oxygen more than was used during that time in oxidizing food substances and body-fat, while in the day -half of the ex- periment more oxygen was thus used than was supplied from without, the liemainder (159.99 grms.) evidently be- ing drawn from a supply previously laid up in the bodv. In the earlier experiments of both Pettenkof er and Yoit and Henneberg, the storing up of oxygen took place chiefly, as in this case, in the night, but further investiga- tions showed that this was by no means always the case. It would seem, from these experiments, as if the healthy animal body were constantly either storing up or giving off oxygen, the two processes, as a rule, nearly balancing each other in the course of twenty-four hours, while com- plete equilibrium is seldom reached in that time. The significance of this fact we shall consider later. Decompositions of the Nutrients in the Body. — The albuminoids of the food and tissues are believed to split up, by numerous intermediate steps, into urea and fat.^ In the herbivora there are also formed varying quantities of hijpjpuric acid, according to the fodder and the species of animal, but the latter always represents a far smaller part of the decomposed albuminoids than the urea, and often disappears almost completely from the list of the substances formed and excreted as the result of tissue-change. The urea is rapidly taken up by the blood, separated from it again in the kidneys, and excreted in the urine ; it can and ought never to be stored up in the healthy organ- ism. In the normal blood and in the tissues are found only inconsiderable traces of it, although the total quan- * See the chapter on the " Formation of Fat." 88 MANUAL OF CATTLE-FEEDING. titj wliicli is formed daily in the body of a fattening steei may amount to a pound or more. The nitrogen contained in 100 parts of water-free pro- tein can be separated from it in the form of 33.5 parts of urea. Tlie remainder of the protein, 66.5 parts, after taking up and uniting with 12.3 parts of water, contains the elements for the formation of 51.4 parts of fat and 27.4 parts of carbonic acid. TTie /at, whether formed from the albuminoids or con tained as such in the food, is, according to circumstances, either deposited in the body of the animal, finds appli- cation in the production of milk, or undergoes a complete oxidation in the respiratory process, yielding carbonic acid and water. The fat producible from the albuminoids must always be added to that which is contained, ready formed, in the fodder and resorbed from the digestive apparatus, in estimating the results of a particular method of feed- ing. It is, however, to be observed that, according to the results of late researches, the fat formed in the body out of albuminoids appears to unite more readily with oxygen — that is, to burn easier — than the ready formed fat taken in the food, and this again easier than that which is already deposited in the fat- tissues. The carhhydrates are represented in the body chiefly by sugar, all the other bodies of the group being converted into this substance during digestion, so far as they are not further decomposed. The food of all herbivorous animals contains large quantities of carhhydrates, an ox, for ex- ample, often resorbing into his blood from twelve to eighteen pounds of sugar in twenty-four hours, yet the blood, in its normal state, never contains more than minute traces of this substance, and it is never stored up as such in the body. MANUAL OF CATTLE-FEEDING. 89 The cause of the comparatively small quantity of sugar foimd in the body, notwithstanding the large amounts taken into the blood, lies partly in the fact that the pro- cess of resorption is a gradual one, extending over a con- siderable time, the sugar, after it passes into the cu'cula- tion, being oxidized with comparative rapidity, and partly, as it would appear, in the conversion of the resorbed sugar into an insoluble form by the liver. Glycogen. — The liver, as long as it is in a normal state, contams a substance belonging to the carbhydrate group, and known as glycogen^ in quantities varying according to the diet of the animal. It may be extracted fi-om the liver by hot water, and when purified forms a white, meal-like, amorphous pow- der, tasteless and odorless. In cold water it swells up, and on warming dissolves to an opalescent fluid. It is insolu- ble in alcohol and ether, and is colored dark-red by iodine. All those agents which convert starch and dextrine into sugar produce the same effect upon glycogen. It rotates the plane of polarized light strongly to the right, but does not reduce alkaline copper solution. It w^ll thus be seen that it stands intermediate between starch and dextrine. Its composition is the same as that of starch. Glycogenic Function of the Liver. — K the dead liver, after removal from the body, be washed out b}' water injected through the portal vein till all sugar is re- moved, and if then, after standing for a time, the washing be renewed, the first portions of water that pass contain sugar. The same process may be repeated several times. *' If the liver of any animal be kept for a considerable time before cooking, the amount of sugar which accumu- lates in its substance is so large as to be easily detected by the taste. The liver is decidedly sweets — (J. Le Conte.) 90 MANUAL OF CATTLE-FEEDING. The source of the sugar in these cases is the glycogen of the Hver, which, by some not well understood chemical action, is converted into sugar. The same jprocess takes jplace in the livhig hody. The blood in the portal vein of flesh -fed animals contains no sugar, but the same blood in the hepatic vein, after having passed through the liver, contains a notable quan- tity of this substance, doubtless derived from the glycogen of the liver. These facts were discovered by Claude Bernard in 1853, and are undisputed, but the source of the glycogen of the liver, and its physiological significance, are questions upon which there is a diversity of opinion. In w^hat follows we shall endeavor to present in outline that view which seems, on the whole, most probable, without, however, treating the matter as one that is finally decided. We have already called attention to the great quantity of sugar that may be- taken into the circulation in the course of a few hours. This sugar is largely taken up by the capillariesi of the stomach and intestines, and passes by the portal vein into the liver, while in the general cir- culation only traces of sugar are found. Putting these facts together, the conclusion seems almost unavoidable that the liver has the power of converting sugar into the insoluble glycogen and storing it up, to be gradually reconverted into sugar as the needs of the organ- ism demand. In other words, the glycogen of the liver is a reserve of carhhydrates. The functions of the carbhydrates in the body are, as yet, but imperfectly understood, but there can be no doubt that they play an important part in the animal economy. According to some, the oxidation of these substances and of fat furnishes a large share of the nniscular and other MANUAL OF CATTLE-FEEDING. 91 force exerted hj the body. This does not appear to be fully established, but even if we do not hold this view, we shall see, in a subsequent chapter, that there is strong reason to believe that non-nitrogenous substances play an important part in the preparation of the muscles for the exertion of force, and that a constant supply of them in the blood is an important condition of healthy activity. On the other hand, it has been shown that a large quantity of sugar in the blood is very hurtful. The office of the liver seems to be to arrest the sugar on its way from the portal capillaries and, by converting it into glycogen, to prevent an injurious accumulation of it in the blood, while the glycogen, by its gradual re-conver- sion into sugar, yields a continual supply of this substance. Glycogen may be formed from Protein. — If a sup- ply of sugar to the blood is important or necessary, we should expect to find some provision for it in those animals which take none in their food — i. e., the ca/rnivo7'a. This is, in fact, the case. The liver has the power to form glycogen from albuminoids, as is shown by the fact that that substance is formed in animals fed entirely on albuminoids. This being so, there is no evident reason why the same formation of glycogen from protein may not take place in all animals. Indeed some authorities hold that it does, and that all the albuminoids destroyed in the body are first decomposed in the liver into glycogen, and urea and similar products. It will be shown in a subsequent chapter, however, that under some circumstances fat may be formed from the protein of the food and stored up in the body, and Yoit and his followers hold that the first decomposition of pro- tein in the body yields fat and not glycogen. However this may be, it is certain that a j)art of the protein may 92 MANUAL OF CATTLE-FEEDING. be used in fat formation, and as certain that part of it maj' also be used by the liver as a source of glycogen. Protein as the Sole Source of Glycogen. — The views of the glycogenic function of the liver just stated, though widely accepted, are not undisputed. Many good authori- ties hold that under all circumstances protein is the source whence glycogen is formed. According to this view, the carbhydrates of the food are oxidized in place of the non- nitrogenous products of the decomposition of protein, and protect the latter, so that they are, in part at least, de- posited in the liver in the form of glycogen, to be drawn on when the supply of carbhydrates in the food is insuffi- cient. That is, the liver has the power of preparing carbliy- drate material from protein and storing it up in an insol- uble form until such time as it is needed. , Which of these two theories is true, or whether the truth lies between the two, is as yet undecided, nor is a discussion of the comparative probability of the two views in place here. Oxidations in the Body are Gradual — In the fore- going paragraphs we have, for the sake of simplicity, spoken as if the processes of decomposition and oxidation were very simple and immediate — as if sugar were burned directly to carbonic acid and water, protein split up at once into fat and urea, etc. This is far from being the case. While the final result is as if the oxidations took place in the way spoken of, and while we are therefore justified in so speaking when we look at the chemical changes in the body as a whole, it must always be with the understanding that the changes which actually take place are very nu- merous and complicated, and that both their nature and location are largely hidden from us. The simple fact that MANUAL OF CATTLE-FEEDING. 93 oxygen, after it is taken into the blood, remains for a time in the system, suffices to show that the chemical phenomena in the body differ essentially from those outside it, and this is confirmed by the little we do know of the processes themselves and by the intermediate products, numbered by hundreds, which have been already discovered. Fortunately, however, for the purposes of cattle -feeding we need only to know the final results of all these changes, and these we have indicated above, and shall presently con sider more in detail. § 3. Excretion. As the result of the continued decompositions and alter- ations going on in the body, we have a constant accumula- tion of carbonic acid, water, and urea and other nitro- genous products in the blood. The carbonic acid and urea are poisonous if allowed to accumulate in the system, and the water would produce injurious effects by diluting the blood, and means are therefore provided for the removal of these substances from the body. The Urine. — In its course through the posterior part of the body the blood passes through the kidneys, two bean-shaped organs, in which the urea and other nitro- genous substances coming from the decomposition of the protein of the body are removed from it. The blood also parts here with some of its water, and the excreted liquid, the urine, passes from the kidneys to the bladder and is thence expelled from the body at intervals. Besides urea, the urine of the herbivora contains, as has been already noted, hipjpuric acid, in which form a vary- ing but small proportion of nitrogen is excreted by these animals. In the carnivora its place is taken by uric acid, 94 MANUAL OF CATTLE-FEEDIKG. also a nitrogenous substance. The imne likewise contains traces of various other bodies, nitrogenous and non-nitro- genous, which, on account of their small quantity, are of no special importance here. Excretion of Nitrogen. — In the nitrogenous substan- ces of the urine is contained all the nitrogen of the albu- minoids decomposed in the bodj. This is a most impor- tant fact, and one upon which a large part of the theory of feeding depends, and consequently it is desirable to examine somewhat in detail the eyidence upon which it rests, particularly since its truth is still disputed by some authors. The question is, whether the " sensible " excretions, that is, urine and dung, contain all the nitrogen which leaves the body, or whether any considerable portion of it is ex- creted in gaseous form from lungs and skin. Since, unfortunately, we have no accurate means of de- termining directly whether free gaseous nitrogen is thus exhaled, we are obliged to approach the subject in an in- direct way, and to determine whether, when no gain of flesh is made by the animal, all the nitrogen of the food reappears in the excreta. The earlier experiments on this subject showed, almost without exception, a deficit of nitrogen in the excrements, seldom an excess. Boussingault found, with a horse, a de- ficit of 2-i per cent, of the nitrogen of the food ; with a milk-cow, 13 per cent. ; with hogs, 37 and 55 per cent.; and with a turtle-dove, 34 and 36 per cent. Other ob- servers also obtained a similar deficit, though quite vari- able in amount. The extensive respiration experiments of Regnault and Heiset sometimes showed a slight excretion of gaseous nitrogen and sometimes a slight absorption of that sub- MANUAL OF CATTLE-FEEDING. 95 stance, but the differences observed by them were far smaller than those obtained by most other observers. Bidder and Schmidt * appear to have been the first to express the opinion that nitrogen leaves the body only in the visible excretions ; but their experiments were too few in number to prove the point, and shortly afterward Bis- choff f published the results, of numerous experiments on dogs, in which he observed a considerable deficit, averag- ing 30 per cent. Iloppe-Seyler also found a deficit of 15 per cent, in an experiment in which a dog was fed for seven days exclusively on meat. Voit's Experiments. — Karl Yoit, in Munich, was the first to furnish decisive proof that the urine and dung are the sole channels by which nitrogen leaves the body, and that the nitrogen of the urine is an accurate measure of the amount of nitrogenous matters decomposed in the body. He showed, in his " PhysiologisGh-cheQnische Untersuch- ungeiij'' published in 1857, that the large deficit of nitrogen observed previously was due to faulty methods of experi- ment, and found in his own experiments either an equal- ity between the nitrogen of food and excrements or dif- ferences which were explained very simply by the gain or loss of flesh by the animal under experiment. Since that time a vast number of similar experiments, chiefly on dogs, have been made in the Physiological Insti- tute at Munich by Yoit, in conjunction with Bischoff and later with v. Pettenkofer, which have fully confirmed the results of the earlier ones and have been of the greatest service in elucidating the laws of the formation of flesh in the animal body. The following are a few of the results : J * " Die Verdauungssafte u. der Stoffwechsel," 1853. f " Der HarnstofiE als Mass des Stoffwechsels," 1853. } Wolff : "Ernahrung Landw. Nutzthiere," p. 249. 96 MANUAL OF CATTLE-FEEDING. Duration of Food. NiTBOGEN. DlFFKRENCE. experiments. Days; In food. Grms. In excrements. Grms. Grms. Per cent. 49 6 9 6 12 14 23 8 20 58 3 8 2499.0 306.0 459.0 306.0 612.0 714.0 1173.0 544.0 340.0 986.0 153.0 408.0 2525.6 308.5 460.7 307.2 611.9 718.5 1176.9 544.3 335.2 982.8 152.6 408.3 + 26.6 +2.5 +1.7 + 1.2 -0.1 +4.5 +3.9 + 0.3 -4.8 -3.2 -0.4 + 0.3 1.0 0.7 0.4 0.4 0.0 0.6 0.3 0.1 1.4 0.3 0.2 0.07 That this equilibrium between the excreted and ingested nitrogen was not a chance occurrence in a single animal, is shown bj the fact that it was confirmed in experiments on ^ve different dogs. Experiments on other animals have not been lacking. Ranke and Pettenkofer & Yoit have shown that the same fact is true of men, and an interesting experiment was made by Yoit on a pigeon, an animal with which Boussingault found a deficit of 3-4 and 36 per cent. Yoit fed a full-grown pigeon for 124 days with peas, of w^hich it consumed 3,132.4 grms. (dry weight), while its own weight rose from 371 grms. to 444: grms. The 3,132.4 grms. of peas contained 149.4 grms. of nitrogen, and in the excrements 145.9 grms. were recovered, showing a MANUAL OF CATTLE-FEEDING. 97 loss of 2.3 per cent. In this experiment the weight of the food was more than eight times that of the pigeon, and the amount of nitrogen in the food ten times that in the aniniaL Taking into account, also, the small weight of the animal and the duration of the experiment, the hy- pothesis of any appreciable excretion of gaseous nitrogen becomes untenable. The small deficit observed is largely explained by the fact that the animal gained 73 grms. during the experiment, and was fomid, when killed, to be rich in flesh. Experiments on Domestic Animals.— The impor- tance of Yoit's observations for the founding of a ra- tional theory of feeding, speedily led to experiments on agricultural animals, which showed that, as was to be ex- pected, the same law holds good for them. A large num- ber of experiments, in which various domestic animals have received a fodder which experience has shown to be sufficient to keep them in unaltered condition for long periods, have shown that under these circumstances all the nitrogen of the fodder reappears in the excrements. Oxen, — The earliest observations were those of Ilenne- berg, at the Weende Experiment Station, on oxen. His first experiments, in 1858 to 1859 and 1860 to 1861, agreed in the main with Yoit's results, but, owing to the com- parative imperfection of the experimental methods then available, considerable variations were found in particular cases. Further experiments, however, made in 1865,* with improved methods and apparatus, showed that these varia- tions were due to experimental errors, and most abun- dantly confirmed Yoit's observations, as the following results show: * "Neue Beitrage zur Begriindung einer Rationellen Fiitterung der Wiederkauer," p. 380. 5 98 MANUAL OF CATTLE-FEEDING. No. of Bxperiment. Weight of animal. Lbs. NiTBOGBN PER DAY. DiFFEBENCE. In food. Grms. In excrement. Grms. Grms. Per cent. 1 2 3 5 6 1,403 u (( 1,529 u 135.5 131.0 131.0 161.5 160.0 135.0 132.0 127.5 167.5 156.5 -0.5 + 1.0 -3.5 + 6.0 -3.5 0.4 0.8 2.7 3.7 2.2 Grou\'en "^ also found approximately an equilibrium be- tween the nitrogen of the food and of the excrements of oxen fed on clover hay. A ration of l-i.3 lbs. of clover hay per day and head gave the following results : NiTBOGEN IN DiFFEBENCE. Experiment. Food. Grms. Excrements. Grms. Grms. Per cent. 8 days 10 days 1,087.79 1,506.42 1,153.67 1,463.63 +65.88 -42.79 6.0 2.8 Milk cows. — Experiments on five different cows in three different places — viz., in Munich, by Yoit,t at the Ex- periment Station at Mockern, by G. Kiihn, :f and at the Hohenheim Experiment Station, by E. v. "Wolff § — * Zweiter Bericht liber die Versuchs- Station Salzmiinde, 1864, p. 122. f Zeitschrift fiir Biologie, 1869, p. 118. ^Landw. Versuchs- Stationen, XIL, 450. § Die Versucksstation Hohenheim, 1870, p. 49. MANUAL OF CATTLE-FEEDING. 09 have shown that the visible excrements of these ani- mals also contain all the nitrogen which leaves the body. The following table gives a resume of all the results, expressed in grammes per day and head : Length of feeding. Nitrogen in Difference. Place. Food. Grms. Excre- ments. * Grms. Grms. Per cent. Munich 6 days. 241.5 238.53 -2.97 1.2 Mockern. .. 20 to 25 days. 120.5 122.0 4-1.5 1.2 u 121.0 117.5 -3.5 2.9 i( 117.4 113.1 -4.3 3.6 it 114.5 120.0 +5.5 4.8 (( 114.8 108.4 -6.4 5.6 (( 121.4 113.2 -8.2 6.7 Hobenheim Nearly 6 weeks. 165.2 164.5 -0.7 0.4 it i( 169.1 169.8 +0.7 0.4 Sheep. — In case of sheep, we have to take into account, besides the excrements, the growth of the wool. The fol- lowing results, selected from those obtained by Marcker and E. Schulze f in a large number of experiments at the Weende Experiment Station, show that when this is done the same law holds with sheep as with other animals. * Including the milk. t Jour. f. Landw., 1870, p. 301. 100 MANUAL OF CATTLE-FEEDING. No. of Animal. Live weight. Lbs. Nitrogen of fodder per day. Grms. Nitrogen ex- creted per day. Grms. DIFFERBNCE. Grms. Per cent. Ill 94.7 104.0 100.4 122.1 103.6 135.5 109.5 17.81 17.26 14.40 16.34 14.76 25.37 19.52 16.93 16.12 14.16 17.46 15.15 25.20 19.85 -0.88 -1.14 -0.24 +1.12 +0.39 -0.17 +0.33 4 9 I 6 6 m.&IV.(av) i:&n. " UL &IV. " II 1.6 6.8 2.6 0.7 Ill 1 7 Goats. — The following experiments, made by Stoh- mann * at the Halle Experiment Station, show that in the goat also the excretion of nitrogen takes place in the visible excreta, and that no considerable excretion of gase- ous niti'ogen can occm- : Live weight. Lbs. NiTBOGEN PKB DAT. Difference. No. of the Animal. In fodder. Grms. In excrements and milk. Grms. Grms. Per cent. I II I IL I n I 81.1 63.5 81.4 62.2 85.3 66.0 83.4 23.3 23.0 21.1 21.1 23.9 23.7 24.8 23.0 22.2 21.5 21.4 23.5 23.6 24.3 -0.3 -0.8 +0.4 + 0.3 -0.4 -0.1 -0.3 1.3 3.5 1.9 1.4 1.9 0.5 1.4 Zeitschrift fiir Biologie, 1870, p. 204. MANUAL OF CATTLE-FEEDING. 101 For the sake of brevity, no description of the fodder has been given in any of the above experiments. It is suffi- cient to say that it was found by experience to be just sufficient to maintain the animals, and that the latter did not appreciably gain or lose during the trials. The duration of the feeding, when given, refers in most cases to the total length of time dui-ing which the fodder was used ; the actual investigation of dung and urine usually ex- tended over 7 to 10 days. Investigations of the Respiratory Products. — The experiments which we have already described have shown conclusively that no appreciable excretion of nitrogen takes place through limgs and skin, and direct investigations of the respiratory products have only confirmed this fact. It is true that we have no means of accurately determining how much free nitrogen is exhaled, but any ammonia that may pass off in this way can be very exactly determined. Such experiments have been executed, and have all shown that only minute quantities of this gas are excreted. Thus Grouven,^ in experiments on twenty-nine different individuals, obtained the following amounts of ammonia per 1,000 lbs. live weight per day : Grms. Grms. Man 0.287-0.510 Sheep 0.340-0.585 Boy 0.457-0.541 Dog 0.663-1.350 Ox 0.206-0.614 Horse 0.259 Cow 0.174-0.392 Ass .. 0.673 Calf 0.774 Goat 0.585 Hog 0.921 Other observers have obtained equally small and unim portant amounts. Quite recently, Seegen and Nowak,f in Yienna, by a * Zweiter Salzmiinder Bericht, 1864, p. 235. f Biedermann's Central Blatt, 1879, p. 593. 102 MANUAL OF CATTLE-FEEDING. peculiar arrangement of the respiration apparatus, claim to have showTi an exhalation of free gaseous nitrogen by various animals; but the method adopted by them de- mands such extraordinarily accurate analyses that the results obtained can as well be attributed to analytical errors as to an actual excretion of free nitrogen. Determination of Gain or Loss of Flesh. — In the foregoing paragraphs we have presented, somewhat at length, some of the evidence which shows that nitrogen is excreted to any considerable extent only in the visible ejecta. This evidence could have been greatly amplified were it necessary, but enough has been given to prove tlie point in question. The value of this knowledge lies in the fact that by virtue of it we can determine easily and exactly whether an animal is gaining or losing nitrogenous constituents, i.e., flesh. We need only to compare the amount of nitro- gen in the digested portion of the daily fodder of the ani- mal with that daily excreted in its urine ; or, more simply still, to compare the total amount of nitrogen in the f oddei- with that of all the sensible excrements, both urine and dung. If the amount in the fodder is the greater, the difference evidently nnist be still retained in the body as flesh. If, on the contrary, the amount is greater in the excrements, it shows as conclusively that more albuminoids have been decomposed than have been supplied, and that the animal is losing flesh. Furthermore, since the albuminoids contain on an aver- age 16 per cent, of nitrogen, we can, by multiplying the difference found by the factor 6.25, as explained on page 17, calculate the weight of albuminoids corresponding to the observed difference of nitrogen, and thus tell exactly how much flesh has been gained or dost. If the amount MANUAL OF CATTLE-FEEDING. 103 of nitrogen found in the excrements is the same as that given in the fodder, it shows, of course, that neither a gain nor a loss has taken place. In a subsequent chapter we shall see that all our knowl- edge of the laws of the formation of flesh has been obtained in this way, and that consequently the truth of those laws depends on the truth of the view that the urinary nitrogen is a measm-e of the amount of protein decomposed in the body. Excretion of Carbon. — The carbon of the organic matters destroyed in the body is excreted in two ways. Part of it leaves the body in the various urinary prod- ucts, but by far the larger portion is excreted as carbonic acid through lungs and skin, as already described, so that an investigation into the gain or loss of carbon by the ani- mal body requires a determination of the gaseous excreta. Excretion of Hydrogen. — A portion of the hydrogen of the tissues is also excreted through the kidneys, a little of it in combination with carbon, nitrogen, and oxygen, in the urea, etc., but most of it in the form of Avater. Considerable quantities of water are also excreted through the lungs, as is made evident by the visible con- densation of the moisture of the breath on a cold day, and likewise through the skin. CHAPTER Y. METHODS OF INVESTIGATION. The practical result of a particular method of feeding shows itself, if we neglect for the moment the production of milk and wool, in a gain of flesh or fat in the body of the animal and in the production of work. We have, then, to consider more minutely the various circumstances which are favorable or unfavorable to the production of fat or flesh, and by which a greater or less amount of use- ful exertion is made possible to the animal. But before so doing, it will be profitable to cast a brief glance upon the methods used in investigations on these subjects — on the ways and means by whose help our knowledge, especially of the laws of flesh-production, has of late been essentially increased and made clearer. § 1. Determination of Digestibility. Digestion Experiments. — While the pure nutrients are theoretically capable of being wholly dissolved and re- sorbed in the digestive apparatus, yet in practice they are so enclosed in or impregnated by indigestible matters, which protect them from the action of the digestive flu- ids, or the effect of the latter is so modified by the pres- ence of several nutrients at once, tliat a greater or less portion escapes digestion and is excreted in the dung. To determine the digestibility of a feeding-stuff, both the latter and the dung of the animal are carefully weighed, MANUAL OF CATTLE-FEEDING. 105 and analyzed in exactly the same way. The absolute quan- tity of each nutrient which enters and leaves the body be- ing thus known, the difference between the total amount of dry matter in fodder and dung gives the total amount of matter digested, and the difference in the amount of any particular constituent, e. g.^ crude fiber, shows how much of that constituent has been digested. It is a matter of course that the greatest care must be exercised, both in the weighing off and portioning out of the fodder, in the collection of the excrement, and in the preparation of a correct sample for chemical analysis. In fact, a high degree of accuracy has been reached in such " digestion experiments " by the help of various ap- paratus, stall fittings, and other arrangements, as may be seen from the results of control experiments, especially when the animal is of a kind favorable to the attainment of accurate results. The latter is generally the case with the smaller animals, particularly with sheep. The Time occupied in Digestion in the rimiinants is comparatively long ; it has been found by numerous obser- vations, made in various ways with the same result, that after a sudden alteration of the feeding, the remnants of the former fodder are still recognizable in the excrements for as much as five days. Accordingly, in all digestion experiments, the fodder whose digestibility is to be deter- mined must be fed for a period of several days before the excrement can be safely considered as corresponding to the fodder and before a sample can be taken for analysis. This preparatory period must, of course, be long enough to insure the complete elimination of the remnants of the previous fodder ; generally it is extended to at least seven days. This preparatoiy period is the more important since the 106 MANUAL OF CATTLE-FEEDING. fodder undergoes a much more intimate mixture in the long and complex digestive apparatus of the ruminants than in the shorter and simpler one of the carnivora or of man. In the latter it is often possible to distinguish the excrement coming from the new fodder by its appearance simply, and if a little colored fruit be eaten, it fi-equently forms a sharp line of division between the two. The process of digestion in the horse and hog is, indeed, more rapid than in the ruminants ; but, nevertheless, in experiments on these animals, a similar preparatory period is observed, to insure entire accuracy. A Source of Error in Digestion Experiments. — The amount of solid matter digested must be equal at least to the difference between fodder and excrement ; it is, in fact, slightly greater, for the reason that the dry matter of the excrement is somewhat increased by the addition of certain products of the intestines themselves, and especially of por- tions of the bile which escape resorption, so that the appar- ent digestibility of the fodder is decreased by that amount. Some idea of the amount of nitrogenous substance thus excreted, and the consequent error in the determination of the digestibility of the albuminoids, may be obtained by de- termining the nitrogen in the ethereal and alcoholic extracts of the excrement, and also the sulphur in organic combina- tion contained in the aqueous extract. The constituents of the bile are largely soluble in alcohol and ether, while the albuminoids are not ; of the bile-constituents not thus soluble only the taurin needs to be considered, and this is soluble in water and distinguished by a very large content of sulplmr (25.6 per cent.), while its nitrogen amounts to 11.2 per cent. In this way it is not difficult to find the greatest quantity of nitrogen which' may possibly have come from unresorbed biliary substances. MANUAL OF CATTLE-FEEDING. 107 Some experiments made in Weende by E. Scliulze and M. Marcker* showed that this nitrogen, in the case of sheep fed exdiisively on hay, constituted only abont 4 per cent, of the total nitrogen of the excrement and equalled only about 2 per cent, of that of the fodder, so that it could not cause a very considerable error in the determina- tion of the digestibility. In the excrement of swine, which generally consume easily-digestible fodder and therefore excrete comparatively little solid matter in their dung, the quantity of biliary products is indeed relatively greater, and their nitrogen amounts, according to experiments in Hohenheim and in Kuschen, to one-fifth or even one-fourth of the total nitrogen of the excrement, but, owing to the high digestibility of their ordinary fodder, equals only 3 to 6 per cent, of the nitrogen of the latter. These biliary and other products, then, can seriously im- pair the determination of the digestibility of the albumi- noids only when the fodder is extraordinarily poor in nitrogen. For example, it was observed by Grouven, at the Salzmiinde Experiment Station, that full-grown oxen on almost " starvation fodder," amounting to only 5 to 9 lbs. of rye straw, together with non-nitrogenous materials, per day, sometimes excreted more nitrogen in their dung than they received in their fodder. It is therefore difficult to arrive at even tolerably accu- rate results regarding the digestibility of the protein in substances so poor in nitrogen as the straw of the cereals, when these are fed alone ; but with even an approximately sufficient fodder, the influence of the biliary products, etc., is not at all considerable and becomes less the more nitro- genous the fodder, since it has been found, at least in the ♦ Jour. f. Landw., 1871, p. 49. 108 MANUAL OF CATTLE-FEEDING. llolienheim experiments on swine, that the absolute qiian« titj of these products in the excrement is no greater with a rich than with a poor fodder. Digestibility of Fat. — The determmations of the di- gestibility of fat hitherto made in digestion experiments are much less exact than those of the digestibility of albu- minoids. Most of the biliary products are soluble in ether, and as the ordinary fodder of domestic animals contains but a small quantity of fat, by the addition of these pro- ducts to the actual fat contained in the excrement the apparent digestibility of the fat must eyidently be yerj considerably decreased, and the more so the less of it is contained in the fodder. In some experiments by E. y. Wolff, at llohenheim,* on swine, the animals were fed exclusiyely with potatoes — a fodder containing but little fat — and the absolute quantity of crude fat (or, more correctly, of matter soluble in ether) in the excrement was considerably greater than that con- tained in the fodder, amounting to 9.-iS grms., and 10.95 grms. per day and head, against 4.27 grms. and 4.91 grms. in the fodder. But, notwithstanding this source of error, digestion ex- periments yield results for fat which, although by no means absolutely correct, are yet, to a certain extent, com- parable, and haye a certain worth in estimating the yalue of a fodder, though it must always be borne in mind that they are too low, and the more so the poorer the fodder is in fat. AVe haye abeady learned that the results obtained in fodder analysis are only approximate. They do not represent pure substances, but serye, when all analyses are carried out in the same way, to compare different fodders * Landw. Jahrbiicher, VIII., I. Supplement, p. 202. MANUAL OF CATTLE-FEEDING. 109 with each other. The same is of course true of the analy- sis of the excrement, which is purposely made after the same method. Remembering these facts, we comprehend that the determinations of digestibility are likewise only approximations. More accurate results are greatly to be desired, but at present we have no means of obtaining them and must be content with our present methods, which, though confessedly impejfect, have yet been of the greatest service in placing the practice of cattle-feeding on a rational basis. We can imderstand, then, that the pres- ence of these biliary and other products in the excrement is not so great a som-ce of inaccuracy as it might at first thought seem, since their quantity is relatively small and is comparatively constant in the same animal, so that the results of digestion experiments are fairly comparable. At any rate, we may be sure that, if we base our calcula- tions of the amount of fodder to be given for any particu- lar purpose on results obtained by the above methods, the animals will not get less than the calculated amount of nutrients, though they may receive slightly more. § 3. Determination of the Nutritive Effect of a Ration. Production of Flesh. — The method of determining the gain or loss of flesh in an animal, which has been already indicated, is based on the well-established fact that the nitrogen of the urine is an accurate measure of the amount of protein decomposed in the body. If in a digestion experiment, carried out as described in § 1, the urine of the animal be also accurately collected and measured, and the quantity of nitrogen which it contains determmed, we have all the data necessary to determine the gain or loss of flesh. From the determinations of the digestibility of the fodder 110 MANUAL OF CATTLE-FEEDING. we know liow mucli nitrogen lias entered into the system, while the urinary nitrogen tells ns how much has left it ; the difference between the two, of course, is the gain or loss of nitrogen by the body, and since the albmninoids contain, on an average, 16 per cent, of nitrogen, this quan- tity, multiplied by 6.25, gives the gain or loss of dry pro- tein. If it is desired to know the amount of fresh flesh, with its normal content of water and ash, which has been gained or lost, this also can be calculated from the average composition of the latter. Yoit,"^ in all his experiments, reckons, on the basis of his own and other analyses, that fresh flesh, free fi'om fat, has the following composition : Water 75.9 per cent. Ash 1.3 " Dry matter 22.8 " 100.0 Nitrogen 3.4 " Other observers have obtained results differing slightly from this, but not sufficiently to be of serious consequence, and since so many experiments by Yoit and others are calculated on this basis, it will be convenient to follow the example of this eminent investigator. Assuming, then, that fresh, fat-free flesh contains 3.4 per cent, of nitrogen, we have only to multiply the gain or loss of nitrogen ob- served in our experiment by 29.4 (3.4 per cent, x 29.4 == 100 per cent.) to learn how much flesh our animal has laid on or destroyed, wliile similar calculations on the total urinary nitrogen will inform us of the total amounts, re- spectively, of protein or of flesh decomposed in the vital processes. * " Emahmng des Fleischfressers," 1860, p. 304, and Zeitschrift fiir Biologic, 1866, p. 468. MANUAL OF CATTLE-FEEDING. Ill A preparatory period of feeding is, of course, necessary, as explained in the previous section, and tliis must be long enough to allow the body to come into equilibrium with the food, so that the effects of the latter may have fully developed themselves. The experiment proper must also extend over a sufficient time to give a fair average. At least twenty-four hours is necessary for this, but better results are obtained when the experiment covers several days. Finally, it should be remembered that the results ob- tained show, in the first place, only the gain or loss of ni- trogen^ and that the factors used for converting this into protein or flesh are average numbers only, and that, while they are nearly enough true for practical purposes, they are not absolutely accurate in all cases. Production of Fat. — As the production of flesh is es- timated by a comparison of the receipts and expenditures of nitrogen by the body, so the production of fat is esti- mated by the gain or loss of carbon. For this purpose it is necessary to take into account the gaseous products of respiration and perspiration, since the larger part of the carbon excreted leaves the body through these channels. These products can only be estimated with accuracy by means of a special apparatus, first constructed in a practi- cal form by Pettenkofer, in Munich, and now widely used under the name of " Pettenkofer's Respiration Apparatus." The Respiration Apparatus. — The principles of this most important apparatus are well illustrated in an ordinary stove, in which the gases coming- from the fire may represent those coming from the lungs of the animal. As long as the chimney draws, no smoke escapes from the doors and draughts of the stove, but, on the contrary, the air presses from all sides into the stove, to pass out through the chimney. 112 MANUAL OF CATTLE-FEEDING. If, in the pipe conducting the smoke from the stove to the chimney, an exact measurement of the volume of air passing were possible, and if, also, the composition of the air entering the stove and of that passing out could be exactly determined in an aliquot part of it, we should have all the factors needed in order to determine what had been added to the air that entered the stove by the fire inside it. In the respiration apparatus the place of the stove is taken by a small room, constructed of boiler-iron, serving to contain the subject of the experiment. This room has windows, cemented as air-tight as possible into its sides, and a door, provided with slides through which the oat- side air has unhindered entrance. The place of the chimney is taken by large air-pumps which are kept in uniform motion at any required velocity by powerful clock-work, which is wound up continuallj^ by a small steam-engine. In some cases this arrangement of pumps has been replaced by a rotary blower. The air which is pumped out of the saloon is accurately measured by means of a large gas-meter, and in order to obtain an aliquot part of this air, and at the same time to analyze the air as it enters the saloon, small mercury pumps are provided, which withdraw uniformly a certain portion of air from that leaving the saloon and also from the air just before entering it. These portions of air are accurately measured by smaller meters, and their content of water and carbonic acid deter- mined by absorption of the water by sulphuric acid and of the carbonic acid by baryta water. The difEerence in water and carbonic acid between the air as it enters and as it leaves the saloon, calculated on the whole volume of air pass- ing through it, gives the quantity added in the apparatus, i. e., expired by the animal. It will be seen that the above-described apparatus is so arranged that the animal or man experimented upon is under entirely normal circumstances, ^. e. , under the same atmospheric pressure and in an equally pure atmosphere as in a stall or ordinary room. This is a great advantage, because only in this way can the experiment be car- ried on as long as is desirable, and results obtained which are reliable and correspond to natural conditions. By the use of the respiration apparatus, in connection with analyses and weighings of food, drink, dung, and urine, we are able to determine all the materials put into and removed from the body, and thus to know the exact effect of any given ration. MANUAL OF CATTLE-FEEDING. 113 The calculation of the gain or loss of flesh has already been explained. By determining the amount of carbon contained in the carbonic acid excreted through the lungs and skin and in the urea, etc., excreted by the kidneys, and comparing it with the amount contained in the di- gested portion of the food, we can find whether the ani- mal is o^ainino^ or losins' carbon in the same manner as we can determine whether it is gaining or losing nitrogen. If the excreted carbon is less than that contained in the food, the difference must have been retained in the body ; if greater, the excess must have come from the tissues of the body. The gain or loss of carbon, however, may have been in one or both of two forms : viz., fat or albuminoids. If the comparison of the nitrogen in fodder and excre- ments shows that the body has neither gained nor lost albu- minoids, then the carbon gained or lost was all in the form of fat, since the other non -nitrogenous substances in the body are so small in amount that they can be neglected. But every 100 parts of fat contains, on an average (p. 12), 76.5 parts of carbon, and therefore every 76.5 parts of carbon shown by the experiment to have been gained or lost represents 100 parts of fat, or one part of carbon cor- responds to 1.3 parts of fat. The method of calculation is exactly similar to that used in calculating the gain or loss of albmninoids from that of nitrogen. The calculation is essentially the same if a gain or loss of albuminoids has taken place, except that the amount of carbon contained in the latter must be deducted from or added to, as the case may be, that found by experiment before multiplying by the factor 1.3. An example will render this clearer. In an experiment made at the Weende Experiment Sta- tion on sheep, the animals received per day and head 1,216 114 MANUAL OF CATTLE-FEEDING. grammes * of hay, together with the necessary amomit of water. In fodder and excrements were found the follow- ing amounts of carbon and nitrogen ; In Fodder — Hay Water , In Excrement s- Dung , Urme Expired air Retained in body Carbon. Grms. Nitrogen. Grins. 460.1 18.1 0.1 .0 460.2 18.1 202.5 8.45 23.2 7.65 213.8 .... 439.5 16.10 20.7 2.00 Taking first the gain of nitrogen, we find that 2 grms. X 6.25 = 12.50 grms, of protein. 2 " X 29.4 = 58.80 " " flesh. and, therefore, that the animal had gained 58.8 grms, of flesh in twenty-four hours. Taking next the gain of carbon, we have to consider how much of it is due to the gain of flesh, and how much to a deposition of fat. The albuminoids contain on an average (p. lY) 53 per cent, of carbon, and hence the 12.5 grms. of albuminoids gained in this experiment contained Q.6 grms. of this element. Out of the total gain of 20. Y * One gramme = 15.43 grains ; 1,000 grammes = 1 kilogramme = about 2.2 lbs. MANUAL OF CATTLE-FEEDING. 115 grms. of carbon, then, 6.6 grms. were contained in the flesh laid on, leaving Itlr.l grms., which must have been gained as fat. Bnt, as we have seen, one part of carbon is equiva- lent to 1.3 parts of fat, and hence we have — 11.0x1.3 = 18.2 grms., the amoimt of fat gained. So, then, the result of the ration of 1,216 grms. of hay per day was, in this particular case, a gain by the animal of 12.5 grms. of albuminoids and 18.2 grms. of fat in twenty-four hours. By a similar process the gain or loss of water by the body can be determined, and thus the total gain or loss, as shown by the live-weight of the animal from day to day, can be analyzed, and we are enabled to say how much of the gain which may be observed is the valuable flesh or fat, and how much is due simply to a greater or less quan^ tity of water in the tissues, or of food and drink in the intestines. The following table (p. 116) gives the detailed results of the above experiment in the form of a balance-sheet, and will give some idea of the care and labor with which such investigations are conducted. Any loss by the body is, of course, placed on the " con- sumption - ' side of the account, and any gain on the " pro- duction " side. The Live-weight alone, although very valuable for many purposes, gives but a very imperfect idea of the effect of a ration. The live-weight of an animal includes not only the solid matter of its tissues, but also water, the food eaten, and the dung and urine contained in the rectum and bladder ; so that an increase of the live-weight by forty or fifty pounds is capable of many interpretations. 116 MANUAL OF CATTLE-FEEDING. Dry Matter. Water. 1 " 1 s 1 a O Consumption. 2936.5 Food AND Drik^ : 1216.0 Hay 6.0 Salt Grms. 997.4 5.7 1.8 0.8 Grms. 218.6 0.3 1712.7 Grms. 67.9 5.7 1.6 0.8 Grms. 460.1 0.1 Grms. 85.8 0.03 190.3 Grms. 18.1 Grm.s. 584.0 0.27 1714.5 Well-water 1522.5 8 Loss BY Body 587.6 Oxygen pkom Air 587.6 3524.9 76.0 460.2 276.2 18.1 2694.4 Production. 1814.5 Excrements: 1257.0 Dung 424.9 79.7 832.1 477.8 44.0 31.1 202.5 23.2 212.7 1.1 117.5 55.5 8.45 7.65 884.6 557.5 Urine 439 9 1640.1 Respiratory Products: 780 Carbonic acid ... . 567 3 1 5 Marsh gas 0.4 95.4 0.7 0.6 2.1 4.0 858.6 Water 858.6 2.1 35.9 0.75 1.25 763 2 70.3 Gain by Body: 9.5 Wool(includ. fat, etc.) 7 8 Protein 7.4 7.8 17.1 0.9 3.5 4.1 13.1 3.7 1 9 17.1 Fat 1 9 35.9 Water 31 9 3524.9 1 76.0 460.2 276.2 18.1 2694.4 It may indicate a gain of flesh or fat, or both, or it may result simply from an increase of the Avater content of the tissues, or from an increased amount of food, water or The stomach alone of the ox will dung in the intestines. MANUAL OF CATTLE-FEEDING. 117 hold 100 to 150 lbs. of water. The excretion of dung, too, is more or less irregular, especially for the first week or two on a new ration. " Grouven found in many of his feeding experiments that during the first week the amount of dung excreted was often as much as twenty pounds too great or too small." To get the most correct results from live-weight, the animals should be weighed always at the same time in the day, either before or after eating, but always under the same circumstances, so far as possible. With all precau- tions, however, the live-weight of a thousand-pound animal may vary as much as 50 lbs. daily. Stohmann gives the following example : An ox weighed, May 23 1298.3 lbs.* " " " 24 1242.4 " " " " 30 1269.8 '' " " 31 1288.3 " ♦* " June 3 1271.1 " " " " 4 1210.7 " " ♦' " 12 1294.2 " It is evident from the above that the live-weight is a very uncertain criterion for judging of the effect of a ra- tion, and that for scientific purposes, where an accurate knowledge of the gain or loss of flesh and fat is required, it is almost worthless. These remarks are not to be understood as calling in question the practical value of the live-weight. The scales are (or should be) an important adjunct to the stable, but it is all the more necessary, on that account, to know how far their indications can be trusted, while every one who * 1 German lb. equals about 1.1 English lb. 118 MANUAL OF CATTLE-FEEDING. imdertakes to make feeding experiments should be aware of the exceeding ambiguity which attaches to small changes of weight. The foregoing explanations make evident how much labor and care are necessary in order to determine, with any certainty, the nutritive value of even a single article of fodder for a single class of animals, and it is no cause for surprise that the theory of feeding can only reach its complete development in all directions slowly. When the question is only of the gain or loss of flesh, the method of experiment, as we have seen, is much simpler and less laborious and demands less expensive apparatus, than when the effect of the ration as a fat-producer is to be deter- mined ; and it is therefore natural that the laws of " flesh- building" are already very thoroughly explored, while in regard to the circumstances under which the greatest and most advantageous production of fat or work is to be ob- tained we are much more in the dark. CHAPTER YL FORMATION OF FLESH. § 1. Introductory. In the foregoing chapters we have considered the com- position of the animal body and of those substances which serve to nourish it — the nutrients, the manner in which these nutrients are digested and resorbed so as to become part of the body, and in outline the changes which they undergo in the body and the forms in which they are finally excreted from it. We saw that we may regard the body as composed es- sentially of protein, fat and mineral matters. The object of feeding is a production of these several ingredients in greater or less quantity. If an animal is simply to be kept in the same bodily condition — to be wintered, e. g. — we aim only to produce enough to supply the unavoidable destruction of tissue that goes on in every living organism, while in feeding for milk, or in fattening, we endeavor to obtain the most rapid production possible, especially of protein and fat ; but in any case some production must take place. Plainly, then, it is of the highest importance to know the laws that regulate the formation of flesh (protein) and fat, from what ingredients of the food they are formed, and what quantities and proportions of the latter will pro- duce the desired effect most rapidly and cheaply. In this chapter we sliall consider the laws regulating the produc- 120 MANUAL OF CATTLE-FEEDING. tion of flesh, and in the following one those governing the production of fat. The Lavrs of the Formation of Flesh have been most thoroughly studied in the carnivora, but they are essentially the same for all the higher animals. The various races of animals differ, indeed, as regards the fodder which they chiefly consume, as well as in their greater or less digestive power for certain kinds of fodder ; but the real nutrients which are resorbed fi'om the diges- tive apparatus, even with the most varied rations, are always the same, viz. : protein, fat, and sugar, together with water and certain salts. Since, furthermore, in all mammals at least, the corresponding organs are entirely similar in their structure, chemical composition, and func- tions, the decomposition of their constituents must follow the same course, i. e., the substances once resorbed and taken up into the circidation decompose or are laid up in the body according to the same laws. Moreover, the laws derived from experiments on car- nivora have been completely confirmed in their general scope and bearing in all the experiments recently made on herbivora, viz., on oxen, cows, sheep^ and goats, though the total amount of material decomposed or stored up in the body varies according to the proportions of the various classes of nutrients contained in the normal fodder of the animal. The food of the carnivora consists chiefly of protein and fat, while the herbivora consume relatively less of these but large quantities of carbhydrates. The ability of the carnivora and herbivora to resorb the Aarious nutrients is not, however, so different as is gener- ally supposed ; it has been shown, e. (/., that a dog is able MANUAL OF CATTLE-FEEDING. 121 to digest and resorb, daily, as much as 15 grms. of starch per kilogramme of live weight, while a well-fed milk-cow, or even a fattening ox, resorbs from its fodder, daily, not more than 12 to 18 grms. of carbhydrates per kilogramme live weight. Similar facts have been observed regarding the resorption of protein, but not regarding that of fat, which is digested by the carnivora in relatively far greater cj^uantity than by herbivora. A large part of our knowledge of the laws of the for- mation of flesh is due to the labors at Munich of Karl Yoit, at first in conjunction with Bischoff and, later, alone and Avitli v. Pettenkofer. These investigators have made a great number of experiments, chiefly on dogs, de- termining the gain or loss of flesh and the total amount of protein decomposed in the body by the method de- scribed in Chapter Y., and to them belongs the honor, both of having established a reliable method of investiga- tion (see Chapter lY., pp. 9-1-97) and of having applied it successfully to the solution of the important question of the effect of food on the gain or loss of flesh. The results stated in this chapter are largely those of the above-named investigators. Protein Consumption. — In considering the laws of flesh-formation, there are two parallel processes to be dis- tinguished. In the first place, in every living organism a certain quantity of albuminoid matter is daily destroyed in the vital processes, and its nitrogen appears as urea, etc., in the urine. The amount of protein or flesh thus destroyed may vary greatly in different animals, or in the same animal at dif- ferent times, but it can only cease entirely with the cessa- tion of life, and cannot smk below a certain minimum 6 122 MANUAL OF CATTLE-FEEDING. amount without serious derangement of the vital func- tions. This continual and necessary process we shall call protein consumptio?i/^ This, of course, must not be con- founded with the amomit consumed by the animal in its food. It denotes a very different thing. In the second place, from a sufficient and suitable fod- der more protein may be resorbed into the circulation than is needed to supply the consumption under the given circumstances, and this sm-plus produces a deposition of protein and becomes part of the body. Evidently, what- ever decreases the protein consumption and increases the amount deposited in the tissues is so much gained in feeding. The protein consumption is not to be considered as waste, for it is necessary to the vital processes and, as we shaU see, is generally greater the richer the food, but an improperly constituted ration may unnecessarily increase it and result in an unproductive use of fodder. The smaller the protein consmnption can be made, consistently with the proper performance of the vital fiinctions, the more of the protein of the food is available for the production of flesh. *We have seen (Chap. V.) that from the urinary nitrogen we can calculate the amount of either dry protein or fresh flesh decomposed in the body, by multiplying respectively by 6.25 or 29.4. In most of the experiments which have been made on carnivora the results have been expressed as flesh, while in those executed on herbivora the re- sults have been calculated as dry protein. In the one case we should speak of the " consumption of flesh," and, in the other, of the "protein consumption." The two are equivalent, but not equal, the consumption of flesh being 4.7 times the protein consump- tion. In the following pages we shall have occasion to use both ezpres' aions. MANUAL OF CATTLE-FEEDING. 123 § 2. Organized and Circiilatort Protein. Protein Consumption during Hunger. — The follow- ing table * gives, iq grammes, the quantities of urea daily excreted by a fasting dog weighiag about 35 kilogrammes (77 lbs.), the excretion of urea beiag, as we have seen, an exact measure of the protein consumption in the body. No. of Experiment. 11. 5. 14. 15. 16. Previous food per day. 2,500 grms, meat. 1,800 grms. meat and 250 grms. fat. 1,500 grms. meat. 1,500 grms. meat. Grms. Grms. Grms. Grms. Grms. Last day of feeding 180.8 130.0 110.8 110.8 24.7 1st day of fasting 60.1 37.5 29 7 26.5 19.6 2d " 24.9 23.3 18.2 18.6 15.6 3d " 19.1 16.7 17.5 15.7 14.9 4th " " 17.3 14.8 14.9 14.9 13.2 5th " *' 12.3 12.6 14.2 14.8 12.7 6th ♦' " 13.3 12.8 13.0 12.8 13.0 7th *' 12.5 12.0 12.1 12.9 .... 8th " '* 10.1 .... 12.9 12.1 9th ** .... .... .... 11.9 10th " " .... .... .... 11.4 .... It will be observed that in these experiments the protein consumption (as measured by the excretion of urea) was very unequal on the last day of the feeding and the first days of himger ; furthermore, that when food was with- held the protein consumption at once sank, rapidly at first but at last very slowly, till at about the sixth day it became * Voit : Zeitschrift fur Biologic, II., pp. 307-365. 124 MANUAL OF CATTLE-FEEDING. practically the same in all cases and so continued during the remaining days, its amount being represented by the excretion of about 12 grammes of urea. A large number of other experiments gave the same result. The Two Factors determining Protein Consump- tion.— It is plain from the above figures that there are two factors which determine the amount of protein de- stroyed in the body ; a constant one, which caused in these experiments an excretion of about 12 grammes of urea per day, and a variable one, which caused the excretion of very different quantities of urea at first, and which gradu- ally disappeared as the experiments progressed. No. of Experiment. 11. 5. 14. 15. 16. Previous food per day. 2,500 grms. meat. 1,800 grms. meat and 250 grms. fat. 1,500 grms. meat. 1,500 grms. meat. Grms. Grms. Grms. Grms. Grms. Last day of feeding 168.8 118.0 98.8 98.8 12.7 Ist dayof fasting. 48.1 25.5 17.7 14.5 7.6 2d 13.9 11.3 6.2 6.6 3.6 3d 7.1 4.7 5.5 3.7 2.9 4th " " 5.3 2.8 2.0 2.9 1.2 5th " 0.3 0.6 2.2 2.8 0.7 6th " 1.3 0.8 1.0 0.8 1.0 7th " '' 0.5 0.0 0.1 0.9 8th " " -1.9 .... 0.9 0.1 9th " .... -0.1 10th '* .... .... .... -0.6 .... Total* 244.3 163.7 135.3 131.1 29.7 Omitting the negative quantities. MANUAL OF CATTLE-FEEDING. 125 If we ass nine 12 grammes of m-ea as the amount due to the constant factor, and subtract this from the total excre- tion on the several days in these experiments, the remain- . ders will exhibit the action of the variable factor. In the table on the opposite page this has been done. This table shows still more clearly the great influence of the variable factor at first and its speedy disappearance when the suj^ply of food is cut off. Organized and Circulatory Protein. — It is evident from these and a great number of similar residts that the protein of the living body exists in two forms — a compara- tively stable one, which decomposes slowly and yielded in these experiments about 12 grammes of urea per day, and an easily decomposable one, whose amount depends on the food and which is rapidly destroyed when food is with- held. The quantity of the latter is small as compared with that of the former. In experiment 11, for example, where its amount was greatest, its total quantity was only about 3,364 grammes of flesh (244.3 grms. of urea x 13.7Y), while the animal weighed about 35,000 grammes. Yoit designates the stable protein of the body as organ- ized jprotein^ and considers that it makes up the mass of the organs; while the variable and easily decomposing quantity he calls circulatory proteiii. Under the latter he does not include the protein of the blood and lymph, but only the dissolved protein whicli penetrates from these into the tissues and bathes the cells in a nourishing fluid. Some good authorities dispute the correctness of the names circulatory and organized protein, but there is no dispute as to the correctness and importance of the distinc- tion which they imply between the two forms of protein in the body. For our present purpose this is the impor- tant thing, and we shall use Yoit's nomenclature, under- 126 MANUAL OF CATTLE-FEEDING. standing by organized j[>rotein the great mass of slowly decomposing nitrogenous compounds in the body, and by circulatory jprotein the relatively small quantity of easily decomposable albuminoids which it contains. The quantity of circulatory protein in a poorly nourished body is only small, not amounting in hunger to one per cent, of the weight of the organized albuminoids, but its amomit is increased by an abundance of protein in the food, and may, at least in the carnivora, rise to five per cent, or more. But, be the quantity of circulatory protein large or small, the greater part of it, generally seventy to eighty per cent., is consumed in the course of twenty -four hours, and an exactly corresponding quantity of nitrogen excreted in the urine as urea, etc. ; while of the organized protein, at most not more than 0.8 per cent, is consumed — that is, the protein consumption in the body takes place almost wholly at the expense of the circulatory protein. It can be by no means assumed, as was formerly done, that all organs of the body are subject to a rapid metamor- phosis, and that in the course of a comparatively short time the whole organism to the last atom is renewed and rebuilt. This is only the case as regards a few tissues. The blood corpuscles, e. g.^ and the milk glands in the period of their greatest activity, are rapidly destroyed and as rapidly re-formed ; but by far the greater part of the organs have, when once formed, a much greater stability, although the contents of the cells vary much in quantity and quality with the varying food of the animal. The circulatory protein, on the contrary, suffers a continual and rapid destruction, and must be continually replaced by protein from the food. Other Experiments. — That the organized protein of the animal body is destroyed far less easily than the cu*cu- MANUAL OF CATTLE-FEEDING. 127 latory protein, is also indicated by more direct experiments which have lately been made. If by any means it were possible to introduce into the body of an animal which had been deprived of food long enough to destroy its circulatory protein, albuminoids in the form of a living organ from another animal, we should expect that, according to Yoit's theory, these albuminoids would be but slowly destroyed in the body. Forster * at- tempted to accomplish this by the transfusion of blood, and found that the protein of living blood, which may be regarded as organized, was but slowly destroyed in the system, while simple solutions of albumin produced an immediate and considerable increase in the excretion of m'ea. It is noticeable, however, that his results show that albumen thus injected seems to be more slowly decom- posed than that taken in the food. Tschieriewf has compared the behavior of transfused blood with that introduced into the stomach, with the fol- lowing results : Nitrogen giveu. Grms. Nitrogen excreted. Grms. Blood fed 13.19 19.09 , 14.38 0.00 18.53 14.55 ' ' transfused 6.85 " fed 14.43 No food. . 4.65 Blood transfused 10.60 These figures show plainly that the albuminoids of the blood, after they had passed through the digestive appa- * Zeitschrift fiir Biologie, XI., 49G. f Biedermann's ' Central-Blatt fiir Agr. Chem.,' X., 98. 128 MANUAL OF CATTLE-FEEDING. ratus, were much more readily oxidized in the body than before. § 3. Feeding with Protein alone. In order to obtain a clear idea of the various factors which determine tlie consumption of protein, on the one hand, and its deposition on the other, it will be best, in the first place, to consider the phenomena produced when the several nutrients are fed alone, and afterward the effect of two, or of all of them together. Consumption dependent on Supply. — The numerous researches made by Yoit ^ have shown most f idly that the consumption of jprotein in the hody is largely deter- mined hy the suj'jyly ofjyrotein in the food. That the ex- cretion of urea, and consequently the protein consumption, was influenced by the food to a very considerable extent, had already been noticed, but this observer has the merit of havmg fully investigated the subject and given it the prominence it deserved. His experiments were made chiefly on dogs ; the following are some of the results obtained in different experiments on the same dog with a diet of various quantities of pure, fat-free meat : Meat eaten per day. . . . Urea excreted Corresponding to flesh. Grms. Grms. Grms. Grms. Grms. Grms. Grms. 2,000 Grms. 300 500 900 1,200 1,500 2,500 12 32 40 68 88 106 144 173 165 442 552 938 1,214 1,463 1,987 2,387 Orma. 2,660 181 2,498 The consumption of flesh varied from 165 grms. per day during hunger to nearly 2,500 grms. with the largest amount of albuminoids in the food, and almost exactly in * Zeitschrift f. Biologie, III., 1. MANUAL OF CATTLE-FEEDING. 129 proportion to the amount of the latter. In all these ex^ periments by far the larger part of the protein of the food was converted into cirGulatory protein, which was rapidly consumed in the vital processes. That this is always the case o;i a purely albuminoid diet is shown by the scores of similar experiments which might be cited. Similar experiments on our herbivorous domestic ani- mals have given in the main the same result, except that the protein consumption has generally been found to be less in proportion to the weight of the animal than in the carnivora, a fact which, however, as we shall see, is in great part due to the large amount of non-nitrogenous matter in the food of these animals. Gould they be fed on pure protein, as was the dog in the above experunents, it is probable that the protein consumption would be corrc spondingly increased. The Consumption does not depend on the Supply alone. — With the same amount of protein in the food the protein consumption in the body may be very unequal in the same animal at different times, as the following results strikingly show. Meat eaten. Grms. Previous food. Consumption of flesh per day. Grms. Gain or low of flesh. Grms. 2,000. 2,500 grms. meat. 2,229 -271 2,000 " " +250 grms. fat. 2,0G9 - 69 1,500 " 1,920 + 80 200 " " +300 gelatin. 1,753 + 247 1,677 + 323 450 grms. starch. 1,383 + 617 175 " meat + 300 fat. 1,365 + 635 130 MANUAL OF CATTLE-FEEDING. The same amount of food caused in one case a loss of 271 grms. of flesh, and in another a gain of 635 grms., and a corresponding variation in the protein consumption is observed. This can only be explained by the difference in the previous food. Where, by an abundant supply of al- buminoids, a large amount of circulatory jprotein had been formed in the body, a decrease of the albuminoids of the food caused a decrease in the protein consumption, but not to an amount corresponding to the decrease in the supply ; the animal lost flesh. On the other hand, an increased supply of albuminoids caused an increase in the protein consumption ; but the increase, like the decrease in the other case, was not proportional to the increased supply, and a gain of flesh resulted. The figures of the above table refer to the first day of the new feeding, and we gather from them that the protein consumption is depen- dent not only on the amoimt of protein in the food but on the bodily condition resulting from the preceding feeding. Equilibrium soon established with Food Supply. — The gain or loss of flesh observed on the first day after a change in the supply of protein does not usually con- tinue long. Within a short time — usually two to four days— the consumption of protein in the body becomes equal to the amount supplied in the food, and no further gain or loss of flesh takes place. The two following ex- amples may serve to illustrate this. Pood. Previous food. Consumption of Flesh. Day before. Ist day. 2d day. 3d day. 2,500 grms. meat. 2,000 " 1,800 grms. meat. 2,500 " Grms. 1,800 2,500 Grms. 2,153 2,229 Grms. 2,480 1,970 Grms. 2,532 MANUAL OF CATTLE-FEEDING. 131 In each, the protein consumption was in equilibrium with the food supply at the beginning of the experiment. In the first case an increase of 700 grms. in the amount of meat eaten caused a rapid increase in the protein consump- tion, till in three days the two were again nearly in equi- librium. In the second experiment the same thing is observed as to the decrease of the protein consumption. The gain or loss of flesh in either case is very trifling, amounting respectively to 335 grms. and 199 grms. in a dog weighing about 35 kilogrammes. Nearly aU of the addi- tional 700 grms. per day in the first experiment was con- verted into circulatory protein and rapidly destroyed, while in the second the subtraction of 500 grms. per day de- creased proportionately the reserve of circulatory protein and the amount consumed. The experiments given above are simply examples taken from a large number of similar ones, made both on carnivora and herbivora, all of which have given the same result, viz. : the cmimal hody jputs itself^ after a longer or shorter time, into eqidlihrium loith whatever quantity of albuinin- aids it receives in its fodder above that necessary to main- tain it in average condition. That is, a certain minimum quantity of albuminoids is necessary to prevent the starva- tion of the animal. An increase of the supply above this quantity causes a slight gain of flesh for a short time, but a raj^id increase in the amount of circulatory protein and consequently in the protein consumption, and, finally, ex- actly as much nitrogen is excreted in the urine (and milk) as is taken in the food. We might compare the stock of circulatory protein in the body to a mass of water con- tained in a vessel with a small aperture in the bottom. If there is no supply, it quickly runs out. If a small stream of water be let in at the top, a small supply of water may 132 MANUAL OF CATTLE-FEEDIXG. be maintained in the vessel. If a larger stream be ad mitted, tlie deptli of water in the vessel will at once begin to increase, bnt, at the same time, the pressure on the bot- tom, and consequently the rapidity of the outward flow through the aperture, increases, and outflow and inflow soon come into equilibrium. If the supply be diminished, the level of the water sinks till the hydrostatic pressure causes the outflow to again equal the inflow. The Protein Consumption during Fasting is not a Measure of the Amount necessary to sustain Life, as was formerly assumed to be the case. If to a fasting animal we give an amount of protein exactly equal to that daily consumed, this protein is converted into circidatory protein, and tlie consumption is correspondingly increased. In order to maintain an animal in average condition, we must give it, approximately, from two to two and a half times as much protein in its food as is consumed in the body during hunger, and when the food has been rich in albuminoids a much greater quantity is necessary to main- tain the equilibrium once established. AVhen equilibrium is once reached, either by a gain or loss of flesh, as the case may be, exactly the same kind and quantity of food is necessary to keep the animal un- altered in the bodily condition in which it then is. Every state of the bod}^, then, demands for its maintenance a cei-- tain definite fodder, and we cannot well speak of a super- fluous consumption of food by animals as by plants, /. e.y of a whoUy useless and unnecessary excess of some one nu- trient. A toaste of fodder ^ however, often occurs in prac- tice, in so far as more fodder is given than is necessary for the object in view, e. g., in the production of milk or wool and the feeding of draught animals and young cattle. Even in fattening, as we shall see later, the same or a bet- MANUAL OF CATTLE-FEEDIlSrG. 133 ter result may not infrequently be obtained with a fodder somewhat poor in albuminoids than with one containing a very large quantity of them. The Rapidity with w^hieh Equilibrium is estab- lished varies. — It is greater the richer the food is in al- buminoids and the less fat is contained in the body ; in general, therefore, in the carnivora than in the herbivora. The influence of the fat of the body in decreasing the protein consumption is of great importance. It has been proved beyond a doubt that in a fat body, the mass of flesh, the food, etc., being the same, the protein consump- tion is less than in a lean body. It is not, however, sim- ply the absolute quantity of fat, but rather its amount relatively to that of the flesh which is the important point. But not only is the protein consumption less in a fat body, ceteris jparihus^ but the rapidity with which equili- brium is reached after a change in the food is less. The following are the results of two experiments, A on a lean animal (dog), B on a fat one : Increase of meat in food. Grms. Equilibrium on Gain of flesh. Grms. Gam in per cent, of increased food. A B 1,800 1,620 3d day. 6th " 309 1,365 17 84 A smaller increase of protein in the food of the fat ani- mal caused both a relatively and absolutely greater gain of flesh, which also continued twice as long. Numerous other examples of the same eft'ect might be adduced, were it ne- cessary. As a consequence of this fact, a gain of flesh can be made more readily by herbivora than by carnivora, since 134 MANUAL OF CATTLE-FEEDING. the former are, as is well known, much inclined to the lay- ing on of fat, and even when in medium condition gener- ally contain relativ^ely a much larger quantity of that sub- stance than the carnivora. For the same reason we may often increase disproportionately the amount of albumin- oids in the food of the herbivora without ha^^ng to fear that it will all be converted into circulatory protein and rapidly consumed. Good results may often be attained in this way, but we should never, with these animals, leave out of account the bodily condition caused by the previous foddering. In the beginning of fattening, especially, the most appropriate fodder must be essentially different ac- cording to whether we have to do with lean and "run down " animals or with those which are already in good condition. Effect of Salt on Protein Consumption. — A mod- erate addition of salt to the fodder increases the circulation of the juices of the body, and consequently the protein con- sumption ; but the salt secures advantages, especially in the herbivora, which have already been spoken of. The feed- ing of salt is therefore especially in place when a greater energy of all the vital functions is desired, as in horses and well-fed working oxen, in young animals, and in male breeding animals, etc., while in fattening only so much should be given as is necessary to render the fodder sa- vory, and is demanded for the normal nourishment of the animal. Another action of salt is to increase the excretion of m*ine, often very considerably. This is observed especially when the animal is pre- vented from much drinking, either purposely or in any other way. For the excretion of larger quantities of salt, more water is necessary, and this is withdrawn, in the first MANUAL OF CATTLE-FEEDING. 135 place, from that excreted by evaporation through the lungs and skin, and, if this is not sufficient, from the body itself. The live weight can therefore sink rapidly when large doses of salt and little water are given, while afterward, on the other hand, if more water is drunk, much of it may be laid up in the tissues, and the live-weight of the animal be again increased. Influence of Water on the Protein Consumption. — Giving too large quantities of salt to animals is to be avoided for still another reason, viz. : that the animals are led to drink large quantities of water, if they have access to it. This causes an increased protein consumption, that is, an increased destruction of valuable fodder materials, especially when the larger quantity of water is not retained in the tissues but is rapidly removed by an increased ex- cretion of urine. Experiments by Yoit on fasting animals showed an in- crease of the protein consumption in this way by as much as 25 per cent., and, according to observations by Henne- berg,* in Weende, on oxen, the increase of the protein consumption, when the amount of water was increased 22.4 per cent., averaged 5.8 per cent. Even the last named increase is by no means insignificant ; it amounts to a third, or perhaps even a half of the protein which otherwise might have been deposited in the body. In any case, in order to get the most advantageous results possible, espe- cially in the feeding of young animals and in fattening, we must avoid everything which involves or leads to an excessive use of water ; e. g.^ too watery fodder, too high a temperature of the stall, too much salt, too much move- ment, etc. This is more especially to be observed in re- gard to sheep, since these animals drink voluntarily much ♦ ''Neue Beitrage," etc., 1871, p. 397. 136 MANUAL OF CATTLE-FEEDING. less water in proportion to the dry matter of tlieir fodder than cattle. In round numbers, the normal amount of water (in food and drink together) may be stated as 4 lbs. per pound of dry matter of the fodder for cattle, and half that quantity for sheep. In milk-giving animals an increased consumption of water is less disadvantageous, and may indeed cause an increased milk-production ; but in this case, also, it is un- doubtedly advisable not to exceed a certain limit as to the proportion of w^ater in the fodder. The EfFeet of Stimulants on the protein consumption seems to be inappreciable. The action on the nervous sys- tem seems to be caused by so minute a metamorphosis of albuminoid substance that it has no significance compared with the total protein consumption in the body. It is, however, another and as yet undecided question whether the increased nervous activity may not cause an increased consumption of fat in the body, as does muscular exer- tion, e. g. § 4. Feeding with Fat or Carbhydrates Alone. Fat alone does not decrease the Protein Con- sumption. — This is showTi plainly by the following results obtained by Voit * on a dog : Grms. Grms. Grms. Grms. Grms. Grms, Grms. Fat per day Flesh consumption. 170 100 185 200 155 300 187 300 165 340 205 350 291 We see at once that even the largest rations of fat are not able to stop or decrease the loss of flesh from the ♦ Zeitschrif t f. Biologie, V. , 329- MANUAL OF CATTLE-FEEDING. 137 body, but seems rather to increase it slightly. This latter effect has been observed in other experiments, and appears to be due to the influence of the fat in drawing into cir- culation the organized protein of the body. It shows it- self still more markedly when, along with the fat, an amount of albuminoids not sufficient to balance the con- sumption is given. The effect is in every case small, and this action of fat is far more than counterbalanced by another which shows itself when it is fed along with a sufficient quantity of protein. Carbhydrates alone do not decrease the Protein Consumption any more than does fat. The same amount of protein is oxidized and destroyed in the body as in the complete absence of food. They differ from fat, however, in the fact that they do not, like the former, slightly in- crease the protein consumption. They are simply without effect on it when fed exclusively. § 5. Feeding with Protein and Fat. The Protein Consumption is determined chiefly by the Supply of it in the Food, just as it is in feed- ing exclusively with albuminoids, and any increase in the amount of the latter causes a corresponding increase in the former. Thus, Yoit {JyOC. cit.) obtained the following results : Grms. Grms. Grms. Grms. Grms. Grms. ( Fat 250 150 233 300 176 259 250 250 270 200 500 502 200 800 778 250 Food-^ (Meat 1,500 Consumption of flesh per day 1,381 138 MANUAL OF CATTLE-FEEDING. It is evident tliat the protein consumption in the body is greater, the larger the amount of protein in the food. The increase, however, is not quite as great as it would have been without the fat ; for, other things being equal. Fat decreases the Protein Consumption, and there- fore increases the deposition of flesh in the body. This is most plainly shown if, after the body is in equilibrium wdth a certain quantity of albuminoids, fat be added to the food. The following example from Yoit's researches illus- trates this fact : Food. Urea per day. Grms. Flesh consump- Date. Meat. Grms. Fat. Grms. tion in body. Grms. July 31 Aug.l " 2 " 3 1,000 1,000 1,000 1,000 100 300 81.7 74.5 69.3 81.2 1,140 1,042 970 1,134 While the animal, when fed with 1,000 grammes of meat, was losing daily about 140 grammes of flesh, the addition of 300 grammes of fat served not only to prevent this loss, but to cause a slight gain. This decrease of the protein consumption is not very considerable in a single day, amounting, in the dog used by Yoit, to at most 168 grammes of flesh, or 45 grammes of dry protein, and varying from 1 to 15 per cent, of the total consumption. Its amount depends not only on the protein and fat of the food but also on the condition of the ani- mal. The greater the amount of circulatory protein in the body, and the less fat it contains, the more of the pro- MANUAL OF CATTLE-FEEDING. 139 tein of tlie food is converted into circulatory protein and consumed. The Decrease of the Protein Consumption is no greater with a large than with a small Ration of Albuminoids, if the quantity of fat remains tlie same. This, indeed, follows from the statements of the first paragraph. An increase of the albuminoids of the food causes more circulatory protein to be formed, and, as a consequence, increases the consumption ; and while the latter is less than it would be without the fat, the difference is not notably, if at all, greater than with the smaller amount of albuminoids. The addition of the fat simply makes the consumption of protein less than it would he without it lender the same circumstances ; but this comparatively small decrease may sometimes make all the difference between a continual loss of flesh from the body and a state of equilibrium, or even a gain of flesh, and thus may be a most important factor in feeding, as illustrated in the experiments in the previous paragraph. A dog weighing 35 kilogrammes (77 lbs.), when fed ex- clusively on pure meat, needs about 1,500 grammes daily in order to remain in good condition and in equilibrium as regards nitrogen. If, instead of this, he receives only 500 grammes, he loses, for a number of days, about 150 grammes daily of his own flesh ; and if, after a considera- ble time, he comes into equilibrium with the smaller ration, he is wasted away and in wretched condition. But if, along with the 500 grammes of meat, about 200 grammes of fat be given, this loss of flesh is speedily checked, and when the protein consumption has come into equilibrium with the supply the animal remains in a Round and well-nourished condition. The addition of 200 140 MANUAL OF CATTLE-FEEDING. grammes of fat so decreases the protein consumption, whicli was before greater than tlie supply, causing the animal to lose flesh constantly, that it is now equal to the latter, or perhaps, in some cases, less, so that a gain of flesh results. That is, we can keep the same amount of flesh on such an animal by feeding 500 grammes of meat and 200 grammes of fat, as by feeding 1,500 grammes of pure meat. In the former case, although the supply of protein is much less, the consumption of it in the body is correspondingly less ; and though the animal may be less lively and ener- getic in its motions on this account, it may still be main- tained in good condition for any length of time on such a ration without the least injury to its health. That the protein consumption, as above stated, is less than when 1,500 grammes of meat are fed is due, in great part, to the decreased supply of albuminoids, the effect of this being the same as when only albuminoids are fed, as was ex- plained and illustrated in the first paragraph of this section. The effect of the addition of the fat is simply to de- crease the consumption a little more ; Lut this little carries it past the pomt of equilibrium, and so prevents the con- tinual loss of flesh which takes place without it. The animal may even gain flesh on such a ration. In this case, therefore, the addition of 200 grammes of fat has saved 1,000 grammes of meat, as compared with a purely flesh diet. We are not, however, to understand that if to the large ration of 1,500 grammes of meat we add 200 grammes of fat, the daily flesh consumption will sink at once to 500 grammes or less, and that 1,000 grammes of flesh will be formed in the body. The protein con- sumption, as already insisted on, is dependent in the first place on the supply of albuminoids in the food, and an in- «tease of the latter correspondingly increases the former ; MANUAL OF CATTLE- FEEDING. 141 SO that, while a large quantity of protein would be daily consumed in the body with the large ration of albumin- oids, the gain of flesh would be no greater, and might be even less, than with the smaller ration. Fat may cause a long-continued Gain of Flesh. — We have seen that any gain of flesh caused by an increase of the albuminoids of the food continues but a short time. The additional albuminoids increase chiefly the amount of circulatory protein in the body and consequently the pro- tein consumption, and equilibrium between the food and the body is speedily established. If, however, the gain of flesh is caused by the addition of fat to the food, the case is different. The fat seems to favor the formation of tissue, i. e., of the more stable organized protein, which is less easily oxi- dized, and consequently, as is fomid by experiment, the gain of flesh caused in this way may continue for a com- paratively long time, so that although the saving of protein effected by the fat may not be great in a single day, the total result is very considerable. It has been already shown (p. 133) that the fat deposited in the body has the same effect in this respect as that of the food. The Gain of Flesh continues much longer on a me- dium than on a large Ration of Albuminoids. — The following experiments (see page 142) illustrate this. The total gain up to the beginning of nitrogen equili- brimn is seen to be in general no greater, and often less, with a large than with a medium ration of albuminoids. In details exceptions are to be expected, since the experi- ments were not all made consecutively, and since not only the supply of food but the bodily condition has much to do with the gain of flesh. In order, then, to obtain as great and long-continued a 142 MANUAL OF CATTLE-FEEDING. Length of Experi- Food. Total gain of flesh. Grms. Gain per day. Grms. Whether ment. . Days. Fat. Gnns. Meat. Grms. nitrogen equilibrium. 32 250 200 250 250 250 150 30-150 250 250 500 800 1,000 1,250 1,500 1,500 1,500 1,800 2,000 1,794 320 375 294 476 104 889 854 353 56 80 125 98 119 10 38 122 117 Not yet. 4 3. Nearly. 3 4 a 10 Quite. Nearly. Quite. Nearly 23 7 3 deposition of flesli in the body of a dog, e.g., as possible, we should not feed large quantities of meat with fat. The absolute quantity of albuminoids in the food does not detennine the gain, but only the protein consumption. Neither is it the absolute quantity of fat that determines the gain, but the relation between the two, together with the bodily condition. This being the case, we should first endeavor to ascer- tain what ratio of albuminoids to fat gave the best results, and then, ha\dng compounded a ration in accordance with this, should endeavor to induce the animal to eat as nmch as possible of it. Two extremes ought to be equally avoided ; too much albuminoids would cause an unneces- sary protein consumption in the body, while if the ration contained an excess of fat, it might be impossible for the animal to eat enough of it to supply himself with the necessary amoimt of protein. MANUAL OF CATTLE-FEEDING. 143 In the fodder of the herbivora the action of fat in de- creasing the protein consumption does not show itself so plainly, its action being masked by the presence of large quantities of carbhydrates, which, as we shall see, have an effect similar to that of fat. Moreover, the amount of fat in the fodder of the rumi- nants cannot safely exceed a certain easily-reached limit. Small quantities of fat exert in general a favorable influ- ence ; larger quantities, however, are often very injurious, causing disturbance of the digestion and an increasing lack of appetite. The different modifications of fat, however, behave very differently in this respect, and the fat of the food certainly deserves attention, especially in the feeding of young animals and in fattening, and likewise in case of horses, and in general whenever the fodder is rich in al- buminoids. § 6. Feeding with Protein and Carbhydrates. The Carbhydrates act analogously to Fat on the consumption of protein and its deposition in the body. Like it, they do not suspend the protein consumption, wliich increases or decreases with the amount of protein in the food ; like it, they decrease the protein con- sumption somewhat, but not greatly; like it, too, they enable an animal to subsist or even gain flesh on a mucli smaller quantity of albuminoids in its food than would suffice were the ration composed of pure protein. The action of the carbhydrates on the formation of flesh has been investigated both in carnivorous and herbivorous animals. In the previous sections we have been occupied exclu- sively with experiments on carnivora, for the reason that 144 MANUAL OF CATTLE-FEEDING. it is practically impossible to feed herbivorous animals on pure protein or protein and fat ; but the general principles deduced fi-om the experiments on carnivora are applicable also to herbivorous animals. In the present section we shall give special prominence to experiments on domestic herbivorous animals, and shall take occasion to point out, in passing, some confirmations of the results obtained on carnivora by Yoit and others. The ordinary fodder of herbivorous animals, leaving out of consideration, for the present, water and mineral matters, consists essentially of protein and carbhydrates with small quantities of fat. A large number of experiments on these animals have been made. As of especial importance for our present purpose may be mentioned those of Grouven,"^ at Salz- miinde, and of Henneberg & Stohmann,t at Weende, on oxen ; those of G. Iviihn & M. Fleischer, j;. at Mockern, on milk cows ; and those of E. Schulze & M. Marcher, § in Weende, on sheep. Of these, the Weende experiments on oxen in particular are of the highest value, both for oiu* present purpose and many others, halving been executed in the most careful and thoroughly scientific manner. The Protein Consumption is Determined by the Supply in the Food. — The following experiments on oxen by Henneberg & Stohmann {loc. cit.), in which the amount of protein in the food varies while that of the non-nitrogenous nutrients remains essentially the same, * Z welter Salzmiinde Bericht, 1864. f " Beitrage zur Begriindung einer Rationellen Futterung" der Wie- derkauer," 1864, and " Neue Beitriige," etc., 1871. :{: Landw. Versuchs-Stationen, XII., 197 and 450. § Journal fiir Landwirthschaft, 1870 and 1871. MAKtJAL OF CATTLE-FEEDING. 145 illustrate this fact, which is shown also in all the other experiments cited. The non-nitrogenous matter of the food here includes the fat reduced to its equivalent of starch (p. 157) ; the numbers in the last three columns express dry protein (nitrogen x 6.25) and not fresh flesh. No. of Experiment. Non-nitroge- nous matter di- gested. Lbs.* Protein di- gested. Lbs. Protein consumption. Lbs. Gain of Protein. Lbs. 1860-1861. ,17 10.23 1.50 1.00 0.50 hs 10.10 2.06 1.43 0.63 • |25 14.60 2.50 2.12 0.38 28 14.49 3.37 2.75 0.62 ^21 14.08 2.19 1.13 1.06 (20 13.73 3.00 1.81 1.19 1865. Av. of 5 & 6. 11.60 0.84 0.86 -0.02 Av. of 4,7&8. 11.95 2.52 1.99 0.53 These results show plainly that the addition of more protein to a fodder causes chiefly an increase in the circu- latory protein of the body, and to a far less degree a gain of flesh, and fully confirm the conclusions drawn from sim- ilar experiments on dogs. At the same time it is obvious that in these experiments there was a greater tendency to- ward the laying on of flesh than was the case in those on carnivora ; a larger proportion of the total protein of the * German pounds. 7* 1 lb. German = 1.1 lb. av. 146 MANUAL OF CATTLE-FEEDING. ration and of the added protein went to form organized protein. Some experiments on goats by Stolimann,* which strik- ingly illustrate the influence of the supply on the protein consumption, may also be mentioned. The following table contains all the essential data : Date of Experi- ment. FoDDEB PEB Day. Protein di- gested per day. Grms. Protein consump- tion t per day. Grms. Gain of pro- Hay. Grms. Linseed meal. Grms. tein per day. Grms. 1. May 23-29.. 1,500 100 111.6 66.6 1.9 2. 1 June G-12 .. 1,450 150 125.0 79.4 9.0 3. " 20-26.. 1,400 200 132.2 90.6 11.1 4. July 4-10. . . 1,350 250 150.9 90.1 23.4 5. " 25-31.. 1,250 350 170.5 101.6 18.3 6. Aug. 8-14 . . 1,100 500 193.8 117.9 27.4 7. " 22-28.. 950 650 221.4 143.1 30.6 8. Sept. 5-11.. 800 800 257.2 173.7 27.4 9. " 19-25.. 1,600a. 92.9 56.3 -4.4 10. Oct. 3-9.... 1,600^'. 74.1 41.9 6.4 Nothing could be more evident than the dependence of the protein consimiption on the supply in these experi- ments. We have seen that in a fasting dog the protein con- sumption is at once increased by even the smallest ration of meat. Some experiments by Grouven {J.oc. cit.) seem * " Biologische Studien," Heft 1, p. 121. f Exclusive of the protein contained in the milk, which varied but slightly. MANUAL OF CATTLE-FEEDING. 147 to indicate that the effect on the herbivora may be differ ^ ent. He observed that in full-grown oxen the protein con- sumption was decidedly less on a ration of rye-straw than during hunger, and that the addition of pure non-nitroge- nous nutrients to the straw decreased it still more. Ox No. I. Fodder per day. Live weight. Lbs. Nitrogen digested. Grms. Consump- tion of flesh. Grms. Loss of flesh. Grms. 1,019 959 990 968 5.2 3.2 4.6 950 475 250 230 625 8.7 IbB. straw 336 6.6 " +2.2 lbs. sugar. 6.5 " +3.3 " 176 110 Ox No. II. 791 777 799 781 5.5 2.7 3.0 1,109 360 250 395 640 6.6 lbs. straw 218 5.3 '' -f2.2 lbs. sugar. 5.3 ♦' +-3.3 *' 191 320 Ox No. IIL 1,150 1,155 0.5 1,427 771 1,525 9.2 lbs. straw 757 The accuracy of these results is impaired by the facts that between the experimental periods the animals re- ceived an abimdant but not uniform fodder, and that the preliminary feeding was in each case so short (3 to 6 days) 148 MANUAL OF CATTLE-FEEDING. as to render it doubtful whether the effect of the new fod- der was fully established. Furthermore, the dung often contained almost as much, and sometimes even more nitrogen than the fodder, show- ing that the former contained considerable quantities of nitrogenous matters coming from the body. The result of this, of course, is that the numbers for digested pro- tein and for the consumption of flesh are too low ; those for the loss of flesh (nitrogen of fodder less that of dung and urme), however, are unaffected by this source of error. If we are to accept this result of Grouven's as correct, we must ascribe it to the large quantities of non-nitrogen- ous matter which were digested along with the small amount of protein, and which would tend to diminish the protein consumption. This action of the carbhydrates is seen also in most of the experiments in which these sub- stances were added to the straw. Of somewhat the same nature as Grouven's results are those which show that addition of protein to a fodder poor in this substance may cause a considerable gain of flesh. The experiments by G. Kiihn & M. Fleischer Q^oc. cit.\ on cows, serve to illustrate this. Two cows were fed dur- ing a first period with hay, either alone or with the addi- tion of starch, and in a second period a nitrogenous bye- fodder was added. The hay used contained an unusually small quantity of protein (Nutr. ratio, 1 : 12), and a com- paratively small amount of it was consumed, so that the food in the first period was far from rich. Even the addi- tion of the nitrogenous bye-fodder in the second period did not make it particularly so, but it nevertheless caused a considerable gain of flesh, which continued for some time. The experiments covered, including the preliminary MANtJAL OF CATTLE-FEEDING. 149 feeding, from twenty-two to twenty-four days, and the gain in the last six days was fully equal to that at the be- ginning. The table shows the results obtained during the experiment proper (exclusive of the preliminary feeding), and also the protein consmnption and the gain of protein for the last five days of the feeding with nitrogenous bye- fodder. Cow No. I. Fodder. DIGESTED FEB iJAT. Nutr. ratio 1 : Protein consump- tion per day. Grms. Gain Date. Protein. Grms. Carbhy- drates. Grms. of protein per day. Grms. Dec 26-Jan 6 Hav 393 680 4,800 4,985 12.2 T.3 187 (343 1345 -5.9 Jan. 17-Peb. 1 1 " 27- " If- Hay and rape-cake + 124.7 + 117.8 Cow No. II. Feb. 16-iIar. 3. Mar. 12-27 1 " 22-27 1 Hay and starch . Hay and beans. . 728 5,550 5,570 14.1 7.6 156 40.0 + 182.2 + 181.9 The addition of protein to a ration poor in this sub- stance caused a considerable gain of flesh by the animals. At the same time, it did not fail to affect the protein con- sumption, approximately doubling it in each case. We conclude, then, that in the case of the herbivora protein added to a ration does not pass so promptly and com- pletely into circulatory protein as it does in the carnivora, but may cause a considerable gain of flesh. This inclina- tion toward the formation of organized rather than circu- latory protein seems to be a characteristic of the herbivora, perhaps due in part to the large amounts of non-nitrogen- ous food which they consume and in part to the consider- 150 MANUAL OF CATTLE-FEEDING. able quantities of fat usually laid up in tlieir bodies, and is a circumstance favorable to economy in feedino;. But though increasing the proportion of protein in a ration may cause a gain of flesh, the experiments by Stoh- mann, already cited, show that when the food is already rich in this substance the gain is much smaller and is accompanied by a greatly increased protein consump- tion. Carbhydrates decrease the Protein Consumption. — The following experiments by Yoit "^ on a dog show that Food. Flesh Date of Experiment. Meat. Grms. Carbhydrates. Grms. consumption. Grms. June 23-July 2, 1859 July 2-5, 1859 500 500 300-100 502 564 July 4-10, 18G4 800 800 800 100-400 826 *' 10-19, " 763 " 19-20, " 895 July 23-26, 1864 1,000 1,000 1,000 100-400 1,028 " 26-28, " 902 " 28-Aug. 1, 1864 1,112 June 29-July 8, 1863 July 8- '' 13, " 1,500 1,500 200 1,599 1,454 Jan. 6, 1859 2,000 2,000 200-300 1,991 " 7-11, 1859 1,792 * Zeitschrift f. Biologie, V., 434. MAlSrUAL OF CATTLE-FEEDING. 151 the carbhydrates exert the same influence on the protein consumption as does fat, viz. : render it less than it other- wise would be. In almost every case the effect of the addition of carb- hydrates was not only to decrease the protein consumption but to render it less than the supply, and thus to cause a gain of flesh instead of the loss which had been taking place. The action of the carbhydrates in decreasing the protein consumption is also to be seen in experiments on herbivora, though in these it is seldom so sharply expressed as in the results just given, because these animals, in any case, receive large amounts of carbhydrates and the effect of a further addition is therefore comparatively small. Grouven's experiments show plainly the decrease of the protein consumption caused by the addition of sugar, even to straw fodder, which of itself contains much carb- hydrates and little protein. Some of Henneberg & Stohmann's experiments in 1865 also show this action of the carbhydrates. The quantities are per day and head. a. Fodder Rich in Protein. Ox II. Experiment 7. 8. Protein digested. Pounds. Carbhy- drates and fat digested. Pounds. Nutritive ratio. Protein consump- tion. Pounds. 3.60 2.51 10.95 12.51 1 :4.2 1 :5.0 2.14 1.83 Gain of protein. Pounds. 0.46 0.68 152 MANUAL OF CATTLE-FEEDING. b. Fodder Poor in Protein. Protein digested. Pounds. Carbhy- drates and fat digested. Pounds. Nutritive ratio. Protein consump- tion. Pounds. Gain of protein. Pounds. Ox I. Experiment 2. . . 0.82 7.22 1 : 8.8 0.83 -0.01 (i '' 1... 0.78 9.99 1 : 12.8 0.78 0.00 OxIL 5... 0.89 11.08 1 : 12.4 0.97 -0.08 (I 6... 0.78 12.12 1 : 15.6 0.74 + 0.04 Here, again, an increase of the carbhydrates, though accompanied bj a slight decrease of the protein, changed a loss of flesh into a gain, as well as diminished the pro- tein consumption. Further confirmation of this effect of the carbhydrates is found in the frequently observed fact that in the great majority of cases where the supply of albuminoids is suf- ficient to cause any production of flesh, the greatest relative gain is produced by rations having a wide nutritive ratio, that is, a large proportion of carbhydrates to albumin- oids. This fact is well shown by the following selection fi*om the experiments of Schulze and Marcker {loc. cit.) on sheep, which are arranged according to the imtritive ratio. They were not all made on the same animal, nor at the same time, and are only comparable in a general way ; but, being toler- ably numerous, they are sufficient to illustrate our present point. The results are per day and head. The protein in the daily growth of wool, amounting to about five grammes is not included in the gain of protein. MANUAL OF OATTLE-FEEDING. 163 No. of Experiment, Protein digested. Grammes. Nutritive ratio. Protein consumpt'n. Grammes. Gain of protein. Grammes. Gain in per ct. of amt. digested. Experiment 6 30.6 1 : 17.4 24.3 1.4 4.6 Experiment 12 67.9 1 :9.4 54.8 8.0 11.8 3.... 59.5 1 : 8.9 45.9 9.0 15.1 11.... 68.1 1 : 8.6 56.2 6.8 10.0 2.... 59.7 1 :8.6 49.1 •5.5 9.2 10.... 72.5 1 :8.1 54.7 12.7 17.5 8.... 85.8 1 :7.7 63.6 17.3 20.1 Average .... 14.0 Experiment 7 116.8 1 :4.9 96.0 15.9 13.7 9.... 156.6 1 :3.7 142.5 9.0 5.8 " 17.... 248.3 1 :2.2 237.6 6.1 2.5 Average 7.3 The very wide nutritive ratio of Experiment 6 caused only a very small gain, because the absolute amount of protein was very small, but that any gain at all was made is doubtless due to the decrease of the protein consump- tion by the large amount of carbhydrates. The other experiments show in general that a larger proportion of the protein of the food is applied to the pro- duction of flesh when the food has a medium nutritive ratio than when it has a very narrow one. In detail, ex- ceptions are to be expected, since, as above stated, the experiments were not all made at the same time and the bodily condition has much to do with the effect of a ration. Stohmann's experiments on goats, already described (p. 146), also illustrate the advantage of a medium nutri- tive ratio, as the following table shows ; 154 MANUAL OF CATTLE-FEEDING. I 2 3 4, 5 6. 7 8. Protein digested per day. Grms. Nutritive ratio. Gain of protein per day. Grms. 111.6 5.87 1.9 125.0 5.42 9.0 132.2 5.08 11.1 150.9 4.78 23.4 170.5 4.22 18.3 193.8 3.27 27.4 221.4 2.84 30.6 257.2 2.55 27.4 Gain in per cent. of digested protein. 1.8 7.3 8.3 15.9 10.5 14.3 14.0 10.9 The relative gain of protein increased up to a nutritive ratio of 1 : 4.78, and then decreased. These and many other experiments which might be ad- duced show that a larger proportion of the digestible pro- tein of a ration is applied to productive purposes when that ration also contains abmidance of non-nitrogenous nutrients. We must beware, however, of hastily concluding that a wide nutritive ratio is the most profitable for the pro- duction of flesh. The amount of fodder which an animal can consume is limited, and, if the nutritive ratio be made very \\dde, the absolute amount of protein in the quantity of food daily eaten will be insufficient to supply material for production. Moreover, the actual number of pounds of flesh gained per day is often greater on a ration pretty rich in albumi- noids, as, for example, in the experiments on sheep and goats just cited, though, of course, accompanied by a large protein consumption in the body. The best pecuniary results may, MANUAL OF CATTLE-FEEDING. 165 under some circumstances, be reached by a ration having a rather narrow nutritive ratio and producing a rwpid gain of flesh, even at the expense of an increased protein con- sumption ; while, under other circumstances, a wider nutritive ratio and a slower and more economical produc- tion might be more remunerative. Extremes in either direction, however, are likely to be unprofitable. Carbhydrates may cause a long-continued Gain of Flesh. — ^We saw in the previous section that a fodder of protein and fat could, under proper conditions, cause a long-continued gain of flesh, while the gain caused by an increase of the protein of the food was usually only tem- porary. The same fact is true of feeding with protein and carbhydrates. It is to be remembered, however, that the fodder of our domestic animals always contains considerable quantities of carbhydrates, and that, consequently, the effects of a change from one method of feeding to another are not so sharply manifested as in the carnivora. To this is to be added that the digestive process lasts a considerable time in the herbivora, so that remnants of the old fodder may be resorbed along with the flrst portions of the new, and thus the change of fodder be made in reality a gradual one. In general the gain of flesh produced by a ration con- taining much carbhydrates continues, for a considerable length of time, while that caused by a ration poor in these substances but rich in protein, although it may be greater at first, does not continue as long. For example, in the experiments of Kiihn & Fleischer on cows (p. 149) the addition of protein to a ration con- taining much carbhydrates caused a gain of flesh which continued with but little decrease throughout the experi- ment and would doubtless have lasted some time longer, a 156 MANUAL OF CATTLE-FEEDING. result evidently due to the abundance of non-nitrogenou8 nutrients and their influence in decreasing the protein consumption. The experiments of Schulze ik Miircker (p. 153), on the other hand, furnish a good example of the opposite effect. In Experiment 6 the fodder consisted of hav and starch ; in Experiment 7, of hay and beans. The quantities of digested nutrients per day and head were : Protein. Grms. Carbliy- drates. Grms. Nutritive ratio. Experiment 6 30.6 116.8 536.7 570.5 1 :17.4 " 7 1 : 4.9 Both experiments were on the same two sheep, and the results given are the average of those obtained from both animals. The following table shows the protein consump- tion and the gain of protein by the body for the last day of the hay and starch fodder, and also for several days on the new ration : E*rotein consumption. Grms. April 2 " 3 (new fodder). " 4 " 5 " 6 " 7 " 14 , " 21. 22.6 48.8 76.8 87.6 88.0 89.8 92.8 102 3 Gain of protein. * Grms. 3.0 63.0 35.0 24.2 23.8 22.0 19.0 9.5 * Exclusive of growth of wool. MANUAL OF CATTLE-FEEDING. 157 Here the change from a poor ration to one rich in pro- tein caused at first a very decided gain of flesh, but one that rapidly decreased, sinking to about a third of its original amount in less than a week and nearly disappear- ing in nineteen days. The contrast between this result and that obtained by Kiihn & Fleischer is exceedingly instructive, and shows anew the importance of a proper proportion of carbhy- drates and fat in the food for the economical production of flesh. Carbhydrates equivalent to Fat. — It is an impor- tant fact for the theory of feeding that the decrease in the protein consumption caused by a given quantity of a carbhy- drate is at least equal to, and generally a little greater than that caused by an equal weight of fat. Formerly, when all the non-nitrogenous substances of the food were supposed to be chiefly valuable as fuel to maintain the vital heat of the body, the relative value of fat and the carbhydrates was naturally measured by the amount of heat which equal weights of the two produced when burned ; and it being calculated that one pound of fat produced •about 2.5 times as much heat as one pound of sugar or starch, it was assumed that the fat of the food was 2.5 times as valuable as the carbhydrates, and their so-called respiration equivalents were respectively 2.5 and 1. So far as they serve for the production of heat, these numbers may represent their relative value, but, as we have seen, they have other important functions ; they not only favor the formation of flesh, but also, as we shall learn, of fat. For the former purpose they are fully equal, weight for weight, to fat, and for the latter much more nearly so than is shown by their respiration equivalents. 158 MANUAL OF CATTLE-FEEDING. The importance of this in the feeding of domestic ani- mals is evident. Fodders containing nnich fat are com- paratively costly, and not only that, but are difficult of digestion by herbivorous animals, and an undue amount of them is liable to produce injurious effects. On the other hand, the carbhydrates are cheap, are contained in large proportions in all the common fodders, and are readily consumed and digested by the herbivora. These substances in the food of the herbivora effect what the fat does in that of the carnivora : they decrease the protein consumption, and enable the animal to subsist on a much smaller quantity of the costly albuminoids than would otherwise be necessary. It is owing chiefly to the large quantities of them consumed by our domestic animals that they need comparatively little protein when fed for maintenance, and that when fed for production a part of the digested protein is readily deposited in the body as organized protein. § 7. Nutritive Value of Amides. We saw in Chapter II. that a part of the nitrogenous matter of many feeding-stuffs is not true protein, but con- sists of various bodies, most of which appear to belong to the so-called amide compounds. It becomes, therefore, im- portant to consider the nutritive value of these substances, and all the more important because, until very recently, they have not been considered, or even recognized, in the analysis of feeding-stuifs, and since in many feeding experiments, from whose results important conclusions have been drawn as to the amounts of the various nutrients required in the food of farm animals, feeding-stuffs have been used which MANUAL OF CATTLE-FEEDING. 159 have since been shown to contain not inconsiderable amounts of these bodies. If, as some writers have assumed, they have no nutri- tive value, we must conclude that our domestic animals require considerably less true protein in their food than fias been hitherto thought, while if they have a value in feeding, it is important to know what it is. We shall con- fine our attention here to the amides, since these are the only non-albuminoid nitrogenous matters which have been experimented on, and the only ones which have yet been found abundantly in the common feeding-stuffs. It may safely be assumed that these comparatively sim- ple bodies cannot perform all the functions of the albumin- oids, but it would seem that certain authors have allowed themselves to be carried too far by purely speculative con- siderations when they have pronounced them valueless for animal nutrition. Amides are Decomposed in the Body.— It has been shown by several investigators tliat amides introduced into the stomach are resorbed, and take part in the chemical changes in the body. Schultzen & ^N'encki'^ appear to have been the first to experiment in this direction. They fed a dog, weighing about 16 lbs., with a fixed amount of bread, milk, and water until equilibrium was established betw^een the supply and excretion of nitrogen, and then added to the food various amides. They experimented on acetamide, glycocol, leucin, and tyrosin, and found that all except the first produced a decided increase in the excretion of urea. Acetamide appeared to pass through the system unaltered. With glycocol the following results were obtained : ♦Zeitschrift fur Biologie, VIII., 124. 160 MANUAL OF CATTLE-FEEDING. Date. Pood. Urea per day. Grms. Septembei •24 Bread, milk, and water. Same -f 15 grms. glycocol. it U i( Bread, milk, and water. (< (( ti 3 960 25 3 768 26 7.187 27 9.470 28 3 810 29 3.780 The feeding of glycocol on the 25th and 26th caused a marked increase in the excretion of urea on the 26th and 27th, showing beyond a doubt that glycocol is con- verted into urea. 'No glycocol was found in the urine. The average excretion of urea on the days preceding the glycocol feeding was 3.8285 grammes per day. Total urea on 26th and 27th 16. 657 grms. Urea of two average days 7.657 " Excess caused by 30 grms. glycocol. Urea equivalent to " " " Difference . 9.000 11.970 2.970 =24.8 per cent. It will be seen that nearly 25 per cent, of the glycocol fed is unaccounted for. The authors state that the glyco- col was not absolutely dry and pure, but it is difficult to imagine that so large an error could be thus caused. It seems more reasonable to suppose that under the in- fluence of the glycocol a gain of flesh took place, and this supposition is perhaps supported by the fact that the in- crease in the excretion of urea does not appear till the sec- ond day. It would seem as if a gain of flesh took place at first, and that subsequently the protein consumption in- creased, to fall again when the glycocol was withdrawn. MANUAL OF CATTLE-FEEDING. 161 Such experiments as this, however, are not adapted, as they were not intended, to show the nutritive effect of the substance experimented on. We have seen that in the dog the addition of protein to the previous food causes but a temporary gain of flesh, while the '' protein consumption " is permanently increased, and we should expect that, if amides aided in any way the production of flesh, the effect of a sudden addition of them to the food would be much the same. In an experiment continued for so short a time as this was, the nutritive effect must of necessity be transitory and hard to isolate. At the same time, the above results do not negative the belief that amides are of value as food. The experiment with leucin gave essentially the same results as the one on glycocol. The leucin was prepared from horn, and was not perfectly pure or dry. Date. Food. Urea per day. Grms. October 4 Bread, milk, and water. Same, + 10 grms. leucin. + 30 " " Bread, milk, and water. (( (( it ti U U (( (( 4.979 *' 5 5 045 "■ 6 6 660 *' 7 9 098 " 8 4 380 *' 9 3 936 The average excretion of urea for the days preceding the feeding with leucin was 4.585 grammes per day. Total urea on 0th and 7th 15.758 grammes. Urea of two average days 9,170 '' Excess caused by 40 grammes leucin 6.588 ** Urea equivalent to " " " 9.000 " Difference (=26.8 per cent.) 3.412 " 162 MANUAL OF CATTLE-FEEDING. An experiment on tyrosin showed that a part of this sub- stance was converted into urea, but that a considerable por- tion escaped digestion. Similar experiments by v. Kniei'iem ^ on asparaginic acid and asparagin, gave similar results. They showed that these bodies are converted into urea in the animal body, and gave also a deficit of nitrogen, though a smaller one, amountiug to 9 to 10 per cent, of the amide nitrogen fed. Further experiments by the same author f on hens, with asparagin, asparaginic acid, glycocol, and leucin, gave also the same result, though with a still smaller deficit of nitrogen. In no case, however, was the excretion in ex- cess of the supply in the food. Indications of Nutritive Value. — All these results, while highly interesting, leave the question of the nutri- tive value of amides still in doubt. There are many facts, however, which indicate that they may have a certain value as food. The very fact that they are decomposed in the body is one. Another is, that they are formed from the albuminoids of the food, to a considerable extent, by the action of the trypsin of the pancreatic juice in digestion. It seems hardly probable that the amides thus formed are to be regarded as waste products. Moreover, we have seen that in the plant these bodies may serve as som-ces of pro- tein, and while such synthetic processes are particularly characteristic of vegetable life, they are by no means ex- cluded in the animal organism. That, under certain circumstances, an amide may have a high nutritive value, has been strikingly shown by Her- mann. It had been shown by Yoit and others that gela- tin and similar bodies, belonging to the gelatigenous group ♦Zeitschrift fiir Biologie, X., 279. flbid., XIII., 36. MANUAL OF CATTLE-FEEDING. 163 of compounds (p. IS), are capable of performing the func- tions of circulatory protein, but cannot serve as a source of organized protein. It was known also that when these bodies were decom- posed by acids they yielded essentially the same products as the albuminoids, except that the amide tyrosin was al- ways lacking. Escher,"^ luider Hermann's direction, tried the experiment of feeding a dog with gelatin and tyrosin, and found that the two together could sustain life and cause a production of flesh. The very probable conjectm-e has been advanced, that amides in the food may play the same part that gelatin has been shown to do by Yoit, viz., take the place of a por- tion of the circulatory protein, thus leaving the latter avail- able for the formation of flesh or for other productive pur- poses, and this view seems to be sustained by the experi- ments about to be described. Asparagin a Nutrient. — The only experiments as yet executed with the direct pui-pose of determining the food-value of amides are those of Weiske, Schrodt, and v. Dangel,f at the Proskau Experiment Station, on aspara- gin. A series of experiments on rabbits and another on hens having shown only that albuminoids could not be entirely replaced by asparagin, but giving in other respects indecisive results, a third series was made on two merino- southdown sheep. The plan of the investigation was as follows : The animals were fed at first with a fodder poor in protein (consisting of hay, starch, and sugar) until the excretion of nitrogen in the urine became constant, and the gain of flesh on this ration was determined. Then, in three following periods, the amount of nitrogen in the daily ration * Vierteljahrsschrift der naturf. Ges. in Zurich, XXI,, 36. t Zeitschrift f iir Biologie, XV., 261. 164 MANUAL OF CATTLE-FEEDING. was doubled by tlie addition respectively of protein (Id tlie form of peas), gelatin, and asparagin, while tlie amount of non-nitrogenous nutrients remained practically the same. These additions to the original fodder were made in the opposite order in the two cases, in order that the nutritive effect of the asparagin in each sheep might be compared with that of protein in the other, and the influence of in- dividual peculiarities be thus eliminated. The preliminary feeding was continued in each period until the excretion of nitrogen became constant, and the excrements then collected for five days and analyzed. In the statement of the results which follows, the average per day and head of these five days is given. Period L Ration : Sheep I. and II. , 500 grms. hay, 200 grms. starch, 50 grms. sugar. Protein digested. Grms. Carbhydrates digested. Grms. Fat digested. Grms. Nitrogen in urine. Grms. Gain of protein. Grms. Sheep I.. " II. 32.21 22.86 412.37 412.71 9.89 9.67 3.275 3.388 1.744 0.094 Period II, Ration : Sheep I., 500 grms. hay, 200 grms. starch, 50 grms. sugar, 43 grms. asparagin; Sheep II., 500 grms. hay, 80 grms. starch, 20 grms. sugar, 250 grms. peas. Sheep I . . " II. Protein ♦ digested. Grms. 70.86 83.54 Carbhydrates digested. Grms. 411.25 427.49 Pat digested. Grms. 9.87 14.08 Nitrogen in urine. Grms. 9.958 11.099 Gain of protein. Grms. 8.625 15,169 See Note on opposite page. MANUAL OF CATTLE-FEEDING. 165 Period III. Ration : Sheep I. and II., 500 grms hay, 200 grms. starch, 50 grms. sugar, 53 grms. gelatin. Protein * digested. Grms. Carbhydrates digested. Grms. Fat digested. Grms. Nitrogen in urine. Grms. Gain of protein. Grms. Sheep I.. " II. 66.68 66.38 399.71 401.52 9.23 8.86 8.69 9.95 12.375 4.250 Period IV. Ration: Sheep I., 500 grms. hay, 115 grms. starch, 15 grms. sugar, 200 grms. peas ; Sheep II. , 500 grms. hay, 200 grms. starch, 50 gi'ms. sugar, 53 grms. asparagin. Protein * digested. Grms. Carbhydrates digested. Grms. Fat digested. Grms. Nitrogen in urine. Grms. Gain of protein. Grms. Sheep I.. " II. 71.24 84.03 441.17 424.03 13.34 9.77 9.730 11.497 10.425 12.175 Determinations of sulphur were made in all the experi- ments, and showed that in every case but one (Sheep II. in Period III.) a gain of this element also took place. These results show, beyond all reasonable doubt, that as- paragin, at least, is really a nutrient, and that when added to a fodder poor in albuminoids it may cause a gain of protein by the body, just as we have already seen that the albuminoids may. It probably acts in the way already suggested, viz., by taking the place of a part of the circulatory protein and * To render the results better comparable, the nitrogen of the as- paragin and gelatin has in all cases been multiplied by 6.25 and counted as protein. 166 MANUAL OF CATTLE-FEEDING. protecting it from destruction. That this is so is perhaps indicated bj the fact that a gain of sulphur also took place. All the albuminoids contain this element, while asparagin :b free from it, and hence we may conclude that the pro- tein deposited in the body was derived from the albu- minoids of the food, and was not formed by a synthetical process from the asparagin. An important point is that the gain produced by as- paragin was nearly as gi-eat as that produced by an equiva- lent amoimt of albuminoids. From this it would appear tliat while asparagin cannot alone supply material for the formation of protein in the body, it is fully capable of performing the functions of the so-called circulatoiy pro- tein, 60 far as the production of flesh is concerned, and for this pui-pose is practically just as valuable as protein for increasing the richness of a ration already containing a reasonable amount of that substance. This suggests the question whether much of the so-called circulatory protein of the body may not be simply that portion of the protein of the food which is converted into amides by the action of trypsin and other ferments during digestion. The sup- position seems quite plausible, and is certainly interesting from a physiological standpoint, though of little practical importance for the purposes of cattle-feeding. Other Amides. — Whether what Weiske has shown re- garding asparagin is true of other amides as well, can, of course, be finally decided only by direct experiment ; but in the meantime, while we must beware of drawing too general conclusions from a single experiment, it seem? highly probable that at least those other amides which have been shown to be convertible into urea in the bodj' may contribute to nourish it. But, if this be true, it also follows that these bodies as MANUAL OF CATTLE- FEEDING. 167 tliey occur in fodders, i. e.^ associated with comparatively large quantities of protein, are practically just as valuable for the production of flesh as the latter, since, when feed- ing-stuffs containing them are used, we have essentially the conditions of Weiske's experiments, viz., amides added to a fodder containing considerable true protein, and should expect the same results. The importance of this fact is easily seen. If, for practical purposes, amides are equivalent to protein, it is unnecessary to consider them separately in the formation of feeding standards, while substitution of a part of the protein called for by a feed- ing standard by amides will cause no decrease in the nu- tritive value of a ration, so far as the prodtcction of flesh is concerned. None of the experiments yet made touch the question of the effect of amides on fat production. It may well be the case that they cannot play the important part in this process which the albuminoids appear to, and, on the other hand, it is quite possible that they, like the carbhydrates, may protect the fat of the body from oxidation. Speculation in advance of experiment is fruitless ; but, meanwhile, though the study of the nutritive value of these bodies has but just begun, all the results yet reached warn us against hastily declaring them worthless or the results of chemical analysis of feeding-stuffs false and mis- leading. § 8. Effect of Quantity of Food. A Large Amount of Fodder Causes a Relatively. Larger Gain. — It is self-evident that a large quantity of fodder of the same composition nmst cause a greater depo- sition of flesh in the body than a small one ; but the gain is aot only absolutely, but relatively greater, as is shown 168 MANUAL OF CATTLE-FEEDING. by numerous experiiuents made on oxen, at Weende, by Henueberg & Stolimann. In one case, e. ^., the total quantity of the digestible nutrients in the daily fodder was increased from 17.86 to 19.46 pounds, while the ratio be- tween the digestible albuminoids and the non-nitrogenous nutrients (the nutritive ratio) remained the same. The result was that, after the increase, 32 per cent, of the total quantity of digested albuminoids w^as deposited as flesh, wdiile befoi'e only 18 per cent, had been. The absolute quantities w^ere 1.19 and 0.62 pounds. In other trials, on a ration consisting exclusively of clover-hay, an increase of four or five pounds per day and head in the hay ration caused the amount of protein deposited as flesh to increase from 9 per cent, to 14 per cent., and in another experiment from 11 per cent, to 15 per cent, of the total digested protein of the fodder. That is, out of every hun- dred pomids of digested protem the animals converted into flesh, on the smaller ration, 9 and 11 pounds, on the larger, 14 and 15 pounds. These facts show how exceed- ingly important it is, especially in fattening, to stimulate the animals to the largest possible consumption of fodder consistent with health ; a little more or less may produce an essentially different effect, showing itself perceptibly in a more or less rapid increase of the live weight. CHAPTEE yn. THE FOKMATION OF FAT. § 1. Sources of Fat. The Fat of the Food, when digested and resorbed, may remain undestrojed under suitable conditions, and be stored up in the body ; this is now as certain as that a for- mation of fat from other constituents of the food may also take place. We will, on this point, only refer to the re- sults of some of the later experiments, which, like many on the laws of flesh formation, we owe to the activity of the Physiological Institute at Munich. Carnivorous animals which, by a previous feeding with meat exclusively, have become rich in flesh and compara- tively poor in fat, can be easily made quite fat-free by long fasting ; the time when the minimum of fat remains is easily recognized from the fact that the excretion of urea, which during hunger is very constant, at last m- creases quite suddenly, because with the entire disappear- ance of the fat more protein is consumed in the body. Such an animal, a dog weighing about 20 kilogrammes, after thirty days of fasting, was fed for ^ve days with the greatest possible quantities of pure fat, of which, on an average, 370.8 grammes daily were digested. This is such a large quantity that it is impossible to suppose it to have been completely oxidized in the body, for then 1,040 grammes of carbonic acid should have been excreted 8 170 MANUAL OF CATTLE-FEEDING. daily, while direct determinations of the respiratory pro- ducts of dogs twice as large and in the best condition give much smaller numbers. In the body of the animal, which was killed at the end of the experiment, 1,352.7 grannnes of fat were found on the various organs, instead of the 150 grammes which, ac- cording to other investigations, was the greatest amount that could have been present in the body after thirty days' fasting, so that in this case about 250 grammes daily of the fat of the food remained undestroyed and were de- posited in the body. In numerous other experiments on dogs, too, with a more normal food of meat and fat, and with help of the respiration apparatus, the fact has been confirmed that often a very considerable part of the fat of the food may be retained in the body. The fat, however, must be analogous to the animal fats or easily altered into them, smce entirely foreign fats are either not resorbed from the alimentary canal at aU or are rapidly oxidized. This does not, of course, prevent the fat in the fodder of the herbivora from contributing di- rectly to the deposition of fat in the body, since most of the vegetable fats are very similar in their composition and properties to tlie animal fats. Formation of Fat in the Body. — For the fact of the formation of fat in the body from other substances no special proofs need be adduced ; it is sufficiently evi- dent from daily experience, especially in fattening and in milk-production. But it is of importance to consider the question what nutrients yield chiefly or exclusively the necessary mate- rial for the formation of fat. Naturally only the albuminoids and carbhydrates are to be considered in this connection, for besides these nutri- MANUAL OF CATTLE-FEEDING. 171 ents and the fat itself, tliere are no other organic substan- ces present in such quantity in the fodder, either of the herbivora or carnivora, as to be able to contribute, in any essential degree, to fat-formation. Formation of Fat from Albuminoids. — That fat can be formed from the albmninoids is now denied by no one acquainted with the subject. The fact that the albuminoids in decay, and on treat- ment with alkalies and with oxidizing agents, form vari- ous fatty substances along with other products of decom- position, favors this view. It has also been observed, that in the milk of the same cow the quantity of albuminoids frequently decreases when that of the fat increases, and the reverse. The occasionally observed formation of so- called adipocere also favors this view ; almost all the nitro- genous substances of the body disappear, and in place of the muscles, etc., appears a waxy-looking, fatty mass, solu- ble in ether. Somewhat similar is the fatty degeneration of the muscles and other organs of the living body in cer- tain diseases and not seldom in excessive fattening, of swine, e. g. This fatty degeneration of almost all the or- gans of the body is especially marked in phosphorus pois- oning, and, according to observations made in Munich, it cannot be doubted that fat in this case arises exclusively from the albuminoids, urea being separated from the latter and excreted. Two apparently independent alterations of the tissue metamorphosis appear to occur at the same time ; first, an increased protein consumption, resulting in the pro- duction of urea and fat, and second, a diminished absorption of oxygen by the blood and consequently a decreased oxi- dation of the fat, both processes working together to cause a large deposition of fat in the body. For example, the liver of a man who died of phosphorus poisoning con- 172 MANUAL OF CATTLE-FEEDING. tained m its dry substance the enormous amount of 76.8 per cent, of fat. If a doubt still remained as to the formation of fat from albuminoids, it must disappear on a consideration of the results which have been obtained on healthy animals with an entirely normal food. For example, the eggs of ordi- nary flies have been allowed to develop on pure blood and from seven to eleven times as much fat found in the larvae as was originally contained in eggs and blood together, although the animals had not consumed nearly all the blood ; the excess of fat could only have come from the albuminoids of the food. Yet more important, however, are the numerous experi- ments made by feeding dogs on large quantities of pure (fat-fi'ee) meat. The three following experiments by Yoit & Pettenko- f er * may serve as an example. In these experiments the respiration apparatus was used, and hence the excretion of carbon, as well as of nitrogen, could be determined -• Fifth day of feeding with 1,800 grms. meat. Second day of feed- ing with 2,500 grms. meat. First day of feeding with 2,ooe grms. meat. Nitrogen. Grms. Carbon. Grms. Nitrogen. Grms. Carbon, Grms. Nitrogen. Grms. Carbon. Grms, Fed, 61.20 59.10 0.60 59.70 225.4 35.6 4.3 179.0 218.9 85.00 84.38 1.00 85.38 313.0 50.6 6.7 213.6 270.9 68,0 66.5 0.8 67.3 250,4 Excreted in Urine Dung Respiration.. Total excretion 40.0 5.4 158.3 203.7 Gain ( + ) or Loss (—). + 1.50 + 6.5 -0.38 + 42.1 + 0,7 + 46.7 * Zeitschrift f . Biologic, VII. , 433. MANUAL OF CATTLE-FEEDING. 173 In the second and third experiments especially, while there is no essential gain or loss of nitrogen, there is a gain of carbon by the body larger than any possible ex- perimental error, and which must be interpreted, accord- ing to the principles of Chapter Y., as showing a produc- tion of fat in the body, and that this fat must have been produced from albuminoids is self-evident. In the first experiment the feeding had continued four days, and there the gain of carbon is small, indicating that a gain of fat produced by albuminoids alone does not continue long, a fact which other results confirm. Many other similar ex- periments showing a formation of fat from albuminoids might be adduced. Fat fkom CARBnYDKATES. — Whether fat can be formed from carbhydrates is still a disputed question. Accord- ing to Yoit & Pettenkofer the protein of the body in de- composing takes up the elements of water and splits up into urea and a fat-like substance ; and, as stated on page 88, it has been calculated that 100 parts of protein and 12.3 parts of water, contain the elements of 33.5 parts of urea, 27.4 parts of carbonic acid, and 51.4 parts of fat. They have shown, in experiments shortly to be de- scribed, that the carbhydrates of the food are more easily oxidized in the system than the fat of the food or the fat formed from the albuminoids, and that they protect the lat- ter two from oxidation and thus indirectly aid the forma- tion of fat. Having also shown, by experiments like those just adduced, the possibility of the production of fat from protein, they naturally regard the latter, together with the fat of the food, as the chief sources of fat under all cir- cumstances, and consider the action of the carbhydrates to be simply protective. According to this view the carbhydrates would, at most, 174 MANUAL OF CATTLE-FEEDING. serve for the production of fat only wlien tlie protein and fat of the food were exliausted, or, in other words, when the supply of oxygen in the body was not sufficient to con- sume all the carbhydrates. If we find that, in all experi- ments on fattening, the digestible protein and fat of the food are sufficient to account for the amount of flesh and fat actually produced, we shall have very strong presump- tive evidence that the views of Yoit & Pettenkofer and their followers are correct, though, of course, such evi- dence is of a negative character and can never reach abso- lute proof. If, on the other hand, we find that, in ac- curately conducted experiments, the digestible protein and fat of the food do not suffice to account for the flesh and fat produced within the limits of experimental error, we have a proof that the carbhydrates of the food must have contributed to its formation to the extent, at least, of the observed difference. Experiments on Ruminants. — Unfortunately there have been as yet no extensive investigations in which the fat-production of domestic animals, or of any herbivorous animals, under the influence of a definite and suitable ra- tion, has been determined with scientific accuracy, i. e., by careful determination of all the solid, liquid, and gaseous excretions. In considering this question, we can avail ourselves only of the results of so-called " practical " experiments, in which the nutritive effect of the fodder has been de- termined simply by the increase of the live weight of the animal, or perhaps from the dressed weight, or at best from experiments in wliich the " sensible " (solid and liq- uid) but not the gaseous excretions have been accurately determined. Milk-fat. — In regard to the production of milk -fat by MANUAL OF CATTLE-FEEDING. 175 cows we have three investigations, carried out respec- tively hy Yoit * in Munich, E. v. Wolff t in Hohenheim, and G- Kiihn and M. Fleischer :f in Mockern. In the first a rich fodder was given, in the two others, on the contrary, one less rich in albuminoids. In the following table the sum of the fat of the fodder and the fat which might have been formed from the pro- tein of the latter (51.4 per cent, of the protein consump- tion) is compared with the amount actually found in the milk. The numbers are grammes per day and head : Munich, Experiment a b HoLenheim, " I II I II Mockern, Fat of fodder. Grms, Fat from protein. Grms. Total. Grms. 818.8 401.8 720.6 276.0 308.5 584.5 170.5 160.1 330.6 166.5 171.3 337.8 183.5 79.5 263.0 183.5 69.5 258.0 Fat of the milk. Grms. 577.5 837.3 308.3 290.5 277.5 292.0 In the Munich and Hohenheim experiments, the fat available from the two sources named was more than sufficient to account for that produced in the milk. ]n Mockern, on the contrary, a small excess of milk-fat was found; but even if this excess had been considerably greater, no definite conclusions in regard to its source could be drawn. Equilibrium between the supply and excretion of nitroojen was, indeed, established in the Mock- ♦ Zeit. f. Biologic, 1869, p. 113. f Ernahrung Landw. Nutzthiere, 349. tLandw. V. St., XI 1,451. 176 MANUAL OF CATTLE-FEEDING. em experiments, as in all the others, but whether the ani- mals were also in equilibrium as to carbon or whether the fat of the body took part in the milk-production, as is so often the case with milk cows, even when well fed, could only have been decided with certainty by the help of a respiration apparatus. Exjyeriineiits on Fattening. — Something more definite as to the source of animal fat may perhaps be learned from the results of fattening experiments on domestic animals, if we at the same time consider that, according to the experiments of Lawes and Gilbert in England (see p. 9), the increase of the live weight in fattening has the following composition in 100 parts : Ash. Protein. Fat. Total dry matter. Water. Swine O.OG 2.34 1.47 6.44 7.13 7.69 71.5 70.4 66.2 78.0 79.9 75.4 22.0 Sheep 20.1 Oxen 24.6 Average 1.45 7.53 66.6 75.6 24.4 Of late years a large number of fattening experiments have been executed at the various Experiment Stations, especially w^ith sheep. In these experiments the fodder has been analyzed according to the same methods, the ac- tual increase of weight determined as accurately as possi- ble, and the duration of the experiments made sufficiently long (from two and one-half to fully three months) to nul- lify, to a large extent, the effects of any temporary varia- tions of the live-weight which might occur. If, now, in these experiments, we assume that, according to Lawes & Gilbert's results, 70.4 per cent, of the gain MANUAL OP CATTLE-FEEDING. 177 made consists of fat, we shall have a basis for computing whether the available protein and fat of the food consumed were sufficient to account for the amount of fat actually produced. Obviously, such computations are simply ap- proximate, but at the same time their results have a cer- tain value when derived from a large number of experi- ments. This comparison has been made by the wi-iter in seventy-' seven different experiments, viz., fourteen by Henneberg, in Weende, in 1858-63 ; * six by Stohman, in 1862-63, f and eight in 1861-65, :[: at Brunswick ; nine by E. v. Wolff, in 1870-71, § and ten in 1871-72, || at Ilohenheim ; nine by Henneberg & Stohmann ; T eight by Haubner & Hofmeister, in Dresden ; and twelve by F. Krocker, in Proskau. ^'^ Each one hundred parts of protein oxidized in the body was considered to have yielded 51.4 parts of fat, and to this amount was added the ready-formed fat of the fodder. The result, with one or possibly two exceptions, was that in all cases the protein and fat were sufficient to ac- count for the amount of fat formed, although in some of the experiments little margin was left. E. V. Wolff has separated fifty-nine of these experiments into four groups, according to the amount of digestible protein contained in the fodder, with the following results in pounds per day and head : * Jour. f. Landw., 1858, p. 362 ; 1860, p. 1 ; 1866, p. 303, t Ibid., 1865, 2 Supplement, tibid., 1867, p. 133. § Landw. Jahrb., L, 533. i Ibid., II., 221. 1^ Jour. f. Landw., 1865, Supplement. ** Preuss. Ann. d. Landw., 1869, Sept. and Dec. 8* 178 :manual of cattle-feeding. Digested per Day and Head, Average. Nutritive ratio. Increase of No. of Experiments. Albumi- noids. Lb&. Non-nitro- genous nutrients. Lbs. live- weight per day and head. Lbs. 7 0.220 0.268 0.329 0.384 1.648 1.557 1.588 1.538 1 :7.49 1 :5.81 1 : 4.70 1 : 4.01 111 13 158 20 189 19 , 206 These numbers speak very decidedly for the favorable action of the albuminoids on the fat production ; a greater increase of weight of the animal accompanies a greater supply of albuminoids, while the quantity of the non-nitro- genous nutrients is nearly the same in all the groups, and therefore can have exerted no essential influence on the increase of weight. If we take into account, however, the fact that, in all probability, some of the so-called protein in these experi- ments was really not protein, but amides or similar bodies, which, though they may aid the flesh production, can hardly serve as a source of fat, the number of cases which indicate a formation of fat from carbhydrates will probably be considerably increased. Still more decided results pointing toward a direct par- ticipation of the carbhydrates in the production of fat were obtained in the experiments of Ilenneberg, Kern, and Wattenberg," already referred to for another purpose in Chapter I. In this investigation two sheep were killed at the begin- * Jour. f. Landw., Jahrg. 26, p. 549. MANUAL OF CATTLE-FEEDIISTG. 179 ning of the experiment, and the amount of the various components of their bodies (flesh, fat, bones, tendons, etc.) determined as accurately as possible, while two similar sheep were examined in the same way after having been fattened for several months. The experimenters themselves did not consider the ques- tion of the origin of the fat, but E. v. Wolff * has shown from their results that a portion of it must have been formed from carbhydrates. The carcases of the unfattened and fattened animals had the following composition : Dry and fat- free flesh. Grms. Dry fat. Grms. Fresh bones. Grms. Fresh tendons. Grms. Unfattened 2,465 2,485 5,406 15,077 2,530 2,566 2,488 Fattened 1,818 Difference +20 +9,671 +36 -670 The result of the fattening was almost wholly a gam of fat. The gain of 9,671 grms. of fat does not include the fat of the wool nor the small quantities contained in skin, head, legs, etc., etc., which would probably have amounted to 200 grms. more. This, however, we will leave out of the account. During the time of the experiment the animals digested about 9,490 grms. of protein and 2,551 grms. of crude fat (ether extract). Assuming that the digested ether extract produced an equal amount of fat, which is hardly proba- *Landw. Jahrb., VIII., I. Supplement, p. 180 MANUAL OF CATTLE-FEEDING. ble, and also that the digested protein yielded 51.4 per cent, of its weight of fat, we obtain the following num- bers : Grms. Fat actually gained 9,671 Fat from ether extract 2,554 grms. " " protein (9,490 X 0.514) 4,878 ." Total 7,432 Fat unaccounted for 2,239 It thus appears that at least 2,239 grms. of fat must have been produced from carbhydrates. In reality the amount was considerably greater, however. Not only have we not taken into account the fat of the offal, but the amount of protein available for the formation of fat is less than appears above. In the first place, a considerable growth of wool took place, demanding, of course, a supply of protein, and in the second place, one of the feeding- stuffs used (lucerne hay) has been shown by KeUner "^ to contain a considerable proportion of amides, which were here reckoned as albuminoids! These results indicate, most decidedly, that in these ex- periments a considerable amount of fat was formed fi*om some other materials of the food than fat or protein. Experiments on Swine. — Nearly or quite all the ex- periments which have been made on swine have yielded results favorable to the belief in the formation of fat from carbhydrates. The earliest investigations were those of Lawes & Gil- bert, in 1850, which, on the assumption that the increase in the live weight had the composition determined by them * Landw. Jahrb., VIIL, I. Supplement, p. 243. MANUAL OF CATTLE-FEEDING. 181 in other experiments (see pp. 9 and 176), sliowed, in many cases, a greater gain of fat than could be accounted for by the protein and fat of the food. Later experiments have given similar and even more decided results. An increase of 100 pounds in the live- weight has frequently been obtained with a fodder contain- ing 10 to 15 lbs. of fat and 50 to 70 lbs. of protein. In one case the above gain was made on a fodder containing only 40.8 lbs. of protein and 6.8 lbs. of fat, while the weight of the animals increased from 70.5 lbs. at the beginning of the experiment to 216.5 lbs. at its close. These results appear almost incomprehensible unless we admit a pro- duction of fat from carbhydrates. Weiske & Wildt,* in Proskau, have attempted to solve the problem by experiments on the same plan as those of Henneberg, Kern & Wattenberg on sheep. Of four six- weeks-old pigs, two were kiUed at the beginning of the experiment, and the total quantity of flesh and fat in their bodies was determined. Of the other two, one received a fodder rather poor in protein for 181 days. The second, which was to have been fed with a fodder rich in protein, became sick, and was therefore excluded from the experi- ment. At the close of the feeding, the sound animal was killed and the flesh and fat present in his body determined, as in the two other animals at the beginning of the experiment. On the assumption, now, that the first two pigs had, at the time they were killed, the same composition as the one which was fattened, we have only to subtract the average of the former fi'om the latter to find the amount of flesh and fat produced during the feeding. * Zeitschrift fiir Biologie, X., 1. 182 MANUAL OF CATTLE-FEEDING. Protein. Kilos. Fat. KiloB. Fattened . 2.2835 1.0410 7.0138 XJnfattened 0.8740 Produced. . . . 1.2425 14.3244 6.1398 Digested from food 0.5748 body Fat formed iu 13.0819 5.5650 Protein availa Available prot ble for fat formation sin X 0.514 — 6.724i According to these figures, the protein and fat of the food were sufficient to cover the amount of fat produced. Various circumstances, however, unite to lessen the vahie of the result reached. From some cause, the growth of the animal was unusually slow. Fm-thermore, the fod- der used consisted of potatoes, rye bran, and starch, and at the time when this research was made the presence of amides in potatoes had not been discovered. Since then from 26.8 to 39.9 per cent, of the total nitrogen of pota- toes has been found in various experiments to exist in the form of amides, and if we take this fact into account, the above calculation yields very different results. Out of the total digested protein, 11.1227 kilos, came from the potatoes. Assuming 26.8 per cent, of this to be amides, there remain 8.1419 kilos., making, with 3.2017 kilos, from the bran, a total of 11.3-136 kilos, of true pro- tein digested.* The figures then stand as follows : * On the assumption that protein and amides were digested to the same extent. It is more than probable that the amides were wholly digestible, which would give a still greater deduction. MANUAL OF CATTLE-FEEDING. 18S Protein. Kilos. Fat. Kilos. Produced 1.3425 11.3436 6 1398 From food 5748 Fat formed in body 10.1011 5.5650 Protein available for fat production Available protein x 0.514 — 5.1920 The result is exactly the opposite of that previously ob- tained. The difference is too small to prove a formation of fat from carbhjdrates, more especially as a participation of the amides in fat-building is noi altogether impossible, but it deprives the experiment of all value as a proof that carbhydrates do not furnish material for fat. Some late feeding experiments on swine by E. v. Wolff,* at Hohenheim, have also given results which seem to show quite plainly a formation of fat from carbhydrates. A gain of 100 pounds was made from an amount of fodder contain- ing from 47.1 to 71. 4 lbs. of digestible protein, and from 1.6 to 3.5 lbs. of digestible fat. The larger of these quan- tities could yield, at most, 40.2 lbs. of fat, while, according to Lawes & Gilbert, 100 lbs. mcrease would contain at least 70 lbs. of fat. Experiments on Dogs. — In regard to the dog, we can assert that in no case is the assumption of a formation of fat from carbhydrates necessary. As has already been mentioned, large quantities of fat may be deposited in the body from the fat or the albuminoids of the food ; but in twenty-two respiration experiments made by Petten- * Laudw. Jahrbiicher, VIII., I. Supplement, 238. 184 MAIS^UAL OF CATTLE-FEEDING. kofer & Yoit, the fat deposited in the body was always f iilly accounted for by that which could be formed from the amount of albuminoids decomposed in the body, and was proportional not to the earbhydrates but to the albu- minoids of the food. AVith the same quantity of albumi- noids m the food, an increase of the carbhydi'ates caused no increase in the amount of fat formed, but only an in- creased excretion of carbonic acid, showing that the earb- hydrates were rapidly oxidized in the blood.* On the other hand, an increase in the albuminoids of the food — the quantity of earbhydrates remaining the same — caused a very considerable increase in the amount of fat pro- duced, thus showing an intimate connection between the supply of protein in the food and the formation of fat in the body. Sources of Uncertainty. — Having considered the ex- perimental evidence bearing on the question of the sources of animal fat, it now becomes necessary to consider briefly how much weight attaches to this evidence. It must be admitted at once that the data now at our command are not sufficient to enable us to solve the prob- lem. Ko thorough and accurate scientific study of the subject has yet been made, if we except Pettenkofer & Voit's experiments on dogs. The conclusions drawn in the preceding paragraphs from experhnents on farm ani- * It should be said that, according to Zuntz {Landw. Jahrbucher, VIII. 94), earbhydrates cause no increase in the excretion of carbonic acid ichen introduced directly into the blood, but only when taken into the alimentary canal. According to him, the increased excretion of carbonic acid is caused by the excitation of the nerves of the stomach and intestines. In a practical point of view, however, the result is much the same, since the earbhydrates of the food must be taken into the alimentary canal, and it makes little difference whether the car* bonic acid is produced from them or from the tissues of the body. MANUAL OF CATTLE-FEEDING. 185 mals are to be regarded only as very probable, not as cer- tain. In the first place, we do not know how much fat was actually formed in these experiments. The estimates of its amount, based on the composition of the increase of fattening animals as determined by Lawes & Gilbert, are obviously very uncertain ; and even in such experiments as those of Henneberg, Kern & Wat- tenberg, and of Weiske & Wildt, it is highly improbable that the animals killed and analyzed at the beginning of the experiments had exactly the composition of those re- served to be fattened, and we have no means of judging of the amount of the difference. Again, in all cases we have assumed that 100 parts of protein decomposed m the body gave rise to 51.4 parts of fat. E^ow this number is a purely theoretical one, based on a calculation by Henneberg of the greatest amount of fat which could possibly be formed from a given weight of protein; and, while there can be no doubt that fat is formed from protein, it is very doubtful whether this maximum amount is formed in every, or even in any, case. It is a commonly observed fact that when a chemical com- pound breaks up into simpler bodies, some of its latent energy is set free, either as heat or in some other form. Zuntz ij.oc, cit.j p. 96) has, however, shown that such a formation of fat and urea from protein as we have been supposing, is only possible on the condition that the result- ing products contain all the latent energy of the decom- posed protein, and that none is given off in the decompo- sition. This, Zuntz remarks, is a process wholly without analogy in the animal body, where all decompositions are accompanied by the setting free of considerable quantities 186 MANUAL OF CATTLE-FEEDING. of heat. Without laying too much stress upon this point, we must still admit its importance. If Zuntz's ground be well taken, then it would appear that in all the calculations on this subject we must reduce the amount of fat obtainable from the protein of the food, leaving still more to be formed from other nutrients. Conclusions. — The following conclusions regarding the sources of animal fat appear to be justified by our present knowledge on the subject : 1st. Animal fat may be formed from the fat of the food. 2d. It may be formed from the protein of the food. 3d. Assuming the accuracy of the factor 0.614 for the conversion of protein into fat, the amount of fat produced by the dog is covered by the protein and fat of the food. 4th. Kuminants have in some cases produced less, and in some cases more, fat than could be accounted for by the protein and fat of the fodder. 5th. Swine have, in the majority of cases, produced more fat than could have been formed from the protein and fat of the food. When we consider the fact that the proofs of the for- mation of fat exclusively from protein are essentially negative in their nature, while those of its formation from carbhydrates are direct, it would seem that we must admit that the carbhydrates may serve as a source of fat to swine, and also, under some circumstances at least, to herbivora. This, however, is equivalent to admitting it for all animals, since there are no essential differences known in the nutri- tive processes of the higher animals. With our present imperfect knowledge, we must regard both protein and carbhydrates as sources of fat, while the final settlement of the question, as well as the determina- MANUAL OF CATTLE-FEEDING. 187 tion of the part played by each, must be left to the deci- sion of more exact experiments. Having thus considered at some length the important question of the sources of animal fat, we are prepared to take up the general laws which regulate its formation. It is evident, however, that until we know with certainty the source from whence the fat of the body is derived, our at- tempts to formulate the laws of its production must be more or less tentative. Most of our knowledge upon this subject is due to the labors of Pettenkofer & Yoit at Mu- nich. These investigators hold that fat is not formed from carbhydrates in the body, and their experiments, which were made before many of the facts spoken of in the preceding paragraphs were known, are interpreted in accordance with that belief. If we add to this fact the great labor involved in investigations of this kind, the use of the complicated respiration apparatus being essential, we can readily imderstand why our knowledge of the laws of the formation of fat should be in some respects unsatis- factory. At the same time, what is already known is very valuable and offers important aid to the formation of a rational theory of feeding. § 2. Feeding with Fat Alone. The Fat of the Food protects the Body-fat. — In Pettenkofer & Yoit's experiments^ a dog was in one case allowed to fast for eight days, and in a second experi- ment was fed daily with 100 grammes of pure fat, about the amount which was found to have been oxidized daily in the first experiment. On the eighth day the following results were obtained : Zeitschrift f. Biologie, V., 369. 188 MANUAL OF CATTLE-FEEDIXG. Grms. Grms. Fat eaten Der dav . . . • 100 159 111 +6 Consumption of flesh in body " " fat* '' .... Gain( + ) or loss (-) of fat 138 114 -99 While, as we have ah-eadv learned, fat does not hinder the protein-consumption in the body but rather tends to increase it, when fed alone, the loss of fat is entirely stopped by a quantity equal to that lost in hunger. That is, an increased supply of fat does not, like an increase of albuminoids, augment the consumption, but takes the place of that before consumed, pound for pound. The simplest way of explaining this is by the assump- tion that the fat of the food is more easily oxidized than that already deposited in the body, and that the former therefore possesses itself of the oxygen of the blood and protects the latter from oxidation. A Gain of Fat may accompany a Loss of Flesh. — In another experiment, in which a large quantity (350 grammes daily) of fat was fed, the loss of flesh on the second day amounted to 227 grammes, and at the same time 1S6 grammes of fat were retained in the body. The same fact is shown by the second experiment on p. 172. § 3. Feeding with Protein Alone. Protein can protect the Fat of the Body from Oxi- dation. — The following experiments by Pettenkofer ;assiz relates that on one occasion he captured a shark, which fought as long and fiercely as is usual with these animals, but which, when finally se- cui'ed, was found to have its gills eaten through by para- sites, and almost all its blood replaced by sea-water. (Liebig.) In cases like these, the products of the muscular action being continually removed by the salt solution, etc., the muscles may continue active until their store of force is exhausted. Like a bent spring, the muscle contains a cer- tain amount of potential energy, which the will can use at pleasure ; but when the supply is once exhausted, when the spring has lost its tension, a fm'ther supply of force from without is necessary before more work can be performed. AVe have to consider, then, in what manner and by means of what substances this storing up of energy takes place. Storing up of Oxygen. — It would appear that the storing up of oxygen in the body which has been shown by Pettenkofer & Yoit and by Ilenneberg (see pp. 85-87) to take place under certain circumstances, is connected with the storing up of energy. In the following tables are given the amounts of car- bonic acid excreted and of oxygen taken up in two of Pet- tenkofer & Yoit's experiments which strikingly illustrate this point. The numbers in the column headed " E " are relative, and sliow how many grammes of oxygen appeared in the excreted carbonic acid for every hundred grannnes taken up from the atmosphere. These experiments are included in the averages on p. 207. MANUAL OF CATTLE-FEEDING. 221 Average Diet— Rest. Carbonic acid excreted. Grms. Oxygen taken up. Grms. R. Cam to 6 p. m 533 379 912 235 474 709 175 6 P xM to 6 A. M 58 6 A M. to 6 A M 94 Average Diet — Work. 6 A.M to 6 P M 884.6 399.6 1,284.2 293.8 660.1 218 6pm to 6 a m.. 44 6 A M to 6 A M 953.9 98 It will be observed that while in each case more car- bonic acid was excreted by day than by night, the larger amount of oxygen was taken up during the night. More- over, the numbers in the last column show that at least a very considerable part of the carbonic acid excreted dur- ing the day must have been formed at the cost of oxygen already present in the body, since that taken up from the air during the same time was far less than the amount contained ui the excreted carbonic acid. A comparison of the two experiments also shows that of the increase of the carbonic acid excretion caused by work (372.2 grammes), by far the larger part (351.6 grammes) occurred during the hours when the work was performed, while the oxygen taken up during the same time increased only 58.8 grammes, against 186.1 grammes in the following night. ..z:i MANUAL OJ- rA'J"JLh-i- J-.iJjJNG. P'urtlier experiinentB bj tlie same irjvefftigatorE, while not always yielding as btriking refrults as did these two, (MJiiiirmed in the main the conclusions drawn from them. It was found, it is true, that the storing up of oxygen did not always take place by night, as in these experunents ; but the fact tliat oxygen may be retained in the body in considerable quantities was fully established. One other iujp<^>rtant jx^int was observed m Ilenneljerg's earlier experiments on this subject, viz., that the greatest st-oring up of oxygen tf>^k place in those experiments in which the fodder was richest in albuminoids. These experunents extended over only twelve hours, corresponding to the " day " half of Pettenkofer >^jdy during the same time, thus show- ing a formation of carbonic acid at the expense of oxygen previously stored up. The following summary of the re- Bults shows that this excess of oxygen was, in general, greatest in those cases where most alVjuminoids were fed : Kuinber «f Experi- ment. Prutein of fod- der. Oxygen taken up. Lbfi. Oxyiren in car- bonic acid. Eatio of the two. 1 0.79 4 25 5 42 1 1.28 2 o.e^ 2 C3 4.34 1 1.05 3 . HO 3 20 4.00 1 1.45 5 o.%> 3.83 0.01 1 1.57 6 0.T8 0.20 0.07 1 1.28 1. 2.00 3. (XI 7.13 1 2.38 8 2.01 3.40 7. 0^3 1 2 24 MANUAL OF CATTLE-FEEDING. 223 This alternate ntoring up and giving off of oxygen by the body has also been observed in physiological experi- ments of an entirely different character, which can only be alluded to here. That the storing np of energy is connected with the storing up of oxygen is indicated by a few experiments l)y Pettenkofer & Voit on two diseases in which the patient is almost incapable of nmscular exertion, viz., diabetes and leukaemia. In these experiments the total excretion and the total amount of food wei-e not mucli different from those in health ; but there was no such storing up of oxy- gen as in the healthy organism, and there was also, as is usual in these diseases, an almost entire lack of strength. But Pettenkofer ik Voit's and Jlenneljerg's results are especially valuable for oui* present purpose because they show that musculai- power does not have its origin in a simple oxidation but in the "explosive" decomposition, independently of oxygen, of mateiial already prepared in the muscle, a conclusion to which we are also led by the fact, already noted, that the muscle is able to perfoim work for a considerable time independently of oxygen, provided the resulting decomposition products are re- moved. Conclusions. — We have learned in the foregoing pages that, presupposing the existence of a healthy and well- nourished organism, muscular exertion is possible when the chemical products of the action are removed from the muscles, and when the body has had the ability and op- portunity to lay up a store of latent energy ; that this stor- ing up of energy is effected by the entrance of oxygen from the air into combination with the organic substances of the muscles ; that when work is performed this oxygen reappears in combination with carbon and hydrogen as car- 224 MANUAL OF CATTLE-FEEDING. bonic acid, water, and otlier products ; that this process re- sults in an increased excretion of carbonic acid and water, while the excretion of nitrogen remains, in most cases at least, unaltered ; and finally, that the amount of work per- formed is in many cases greater than can be accounted for by the amount of protein which the m-inary nitrogen shows to have been decomposed. All these facts are well ascertained, and they enable us to fi'ame an h^^othesis which, though confessedly but a rough and approximate one, is still considered by many high authorities to accord more closely with the facts of the case and with our general conceptions of vital activity than those which place the source of muscular power in protein on the one hand, or non-nitrogenous matters on the other. This h^^othesis supposes that during rest some of the substances of the muscle-cells decompose into simpler com- pounds, and in so doing set free their latent energy, and that this energy, instead of appearing as heat, etc., is used to build up out of other constituents of the cell a still more complex compound, containing more potential energy than its components, just as one portion of society may acquire wealth at the expense of another portion without increas- ing the total wealth of the comnnmity. The sul)stances which are thus " s}Tithesized " are pro- tein, non-nitrogenous matter from the blood, and oxygen. The hypothetical compound thus formed, after accumulat- ing to a certain extent, decomposes during rest as rapidly as it is formed. When the muscle is called on to perform work, however, it splits up rapidly, yieldmg carbonic acid, Water, and otlier non-nitrogenous matters, and a nitro- genous compound, and giving forth the amount of force which was required to form it. The non-nitrogenous sub- MATTUAL OF CATTLE-FEEDING. 225 stances wliicli are formed are supposed to be rapidly ex- creted, while the nitrogenous product, instead of undergo- ing furtlier decomposition, is used over again to re-form the hypothetical substance. This view has much in its favor. Various syntheses, more or less like that above outlined, are known to take place in the body ; and, moreover, we have seen that all tlie facts seem to indicate that muscular force originates in a splitting up of some substance in the muscle, rather than in any process of oxidation in the ordinary sense of the word. The hypothesis explains the object of the storing up of oxygen in the body during rest, and its connection with the laying up of a reserve of force : the oxygen enters into the supposed complex compound much as the nitric-acid radicle enters into nitro-glycerine or gun-cotton — it is held in a state of unstable equilibrium, ready to enter into new and simpler relations with its neighboring atoms and to set free the force by which it was placed in its unstable position. The hypothesis also brings that necessity for albuminoids in the food of the laboring animal which practical experience has shown to exist, into harmony with the fact that there is no greater excretion of nitrogen dur- ing work than during rest. Furthermore, it shows why w^e need rest after work. In the first place, the circula- tion must have an opportunity to remove those waste products which accumulate in the working muscle faster than they can be carried off, and in the second place a fresh supply of force must be stored up in the way des- cribed before it is ready to be used at the command of the will. Finally the assumption of a complex " contractile mate- rial" is in harmony with the results obtained by Fick & 10* 226 MANUAL OF CATTLE-FEEDING. Wisliceniis and otliers regarding the force value of the nutrients, since it does not place the source of muscular power in the albuminoids alone but in the joint action of these and of non-nitrogenoiis mattei-s. It is possible that Kellner's results, if confirmed bj further investigation, may modify this hypothesis some- what. They at least suggest that when, under the influ- ence of protracted work, the reserve of '^contractile mate- rial " runs low, the protein of the muscle may be used to supply the deficiency. In any case, it must be remembered that this hypothe- sis is only a provisional one. Much work remains to be done before we can have a full understanding of this im- portant subject, and the chief value of such an hypothesis as this is to co-ordinate and arrange our knowledge, and serve as the basis for further research. § 3. Internal Work. In the two previous sections we have been considering one particular form of work, viz., muscular exertion. As pointed out at the beginning of this chapter, there are other forms of work wdiich, though less obvious, are of equal or even greater importance, and we now turn our attention to these, grouping them under the convenient, if not strictly accurate, name of internal work. The internal work of the body may be of three princi- pal kinds : muscular work of the internal organs, produc- tion of heat, and of chemical changes. Muscular Work of Internal Organs. — The activity of many of the most important internal organs involves considerable muscular action, e. g., in the heart, the respi- ratory muscles, and the digestive apparatus. Of these, MANUAL OF CATTLE-FEEDING. 227 the work of the two former is tolerably constant, and makes pretty uniform demands on the latent energy sup- plied by the food, while the labor performed by the di- gestive apparatus is more vai'iable, being relatively greater with a bulky than with a concentrated fodder, and is like- wise greater at or near the time of feeding than at other times. Henneberg's Experiments. — We have already learned that muscular exertion increases the excretion of carbonic acid, but not notably that of urea. Henneberg * has shown that the same is true of the work of the digestive organs, so far, at least, as the excretion of carbonic acid is con- cerned.- In one series of respiration experiments on sheep the animals were fed chiefly during the day, while in a second series they received most of their fodder in the night. The numbers in the following table give in grammes per day the results obtained on two sheep taken together : Feeding chiefly by Day. Number of Experi- Fodder (Hay). Cabbonic Acid. Of 100 Parts Carbonic Acid. ment. Day. Grms. Night. Grms. Day. Grms. Night. Grms. Day. Per cent. Night. Per cent. 1 and2 1,809 1,824 1,736 624 684 723 877 777 864 756 691 715 54 53 55 46 3 and 4 47 5 and 6. 45 Average 1,790 677 839 721 54 46 * Neue Beitrage, etc. 1871, p. 157. 228 MANUAL OF CATTLE-FEEDING. Feeding chiefly by Night. Number of Experi- FODDEB (Hay). Carbon [c Acid. Of 100 Parts Carbonic Acid. ment. Day Grms. Night Grms. Day Grms. Night Grms. Day. Per Cent. Night Per Cent. 1 and2 590 653 586 1,685 1,588 1,499 719 706 693 806 842 815 47 46 46 53 3 and 4 54 5 and 6 54 Average 610 1,591 706 821 46 54 The increased work caused by the feeding by day in one case, and by night in the other, resulted immediately in an increased excretion of carbonic acid. It is probable that the difference observed in these ex- periments is chiefly the expression of the amount of work involved in chewing and rumination, since the alimentary canal always contains more or less fodder ; but at the same time it gives us a useful hint of the amount of work required in the digestion of the bulky fodder of herbivorous animals. Saving of Work by Concentrated Fodder. — A cer- tain amount of work by the digestive organs is, of course, necessary and unavoidable, but it is evident that the amount of this work will be reduced by the use of as concentrated fodder as possible. That is, the less the proportion of indigestible matters contained in a fodder, the less of the fodder will have to be eaten and worked over by the animal in order that it may obtain the amounts of the several nutrients which it MANUAL OF CATTLE-FEEDING. 229 requires. If we could eliminate the indigestible matters entirely from the fodder of an animal, we should effect the greatest possible economy of work by the digestive organs, and could produce an equal nutritive effect with a correspondingly smaller amount of digestible nutrients, since, as explained on p. 203, the production of work of any kind implies a destruction of the constituents of the body, which loss must finally be supplied by the food. Such an extreme case is purely suppositious, but obviously, the nearer we approach to it by the use of fodders contain- ing a large proportion of digestible matter, the greater will be the saving of work, although we have no accurate data regarding the amount of the saving which could thus be made. In Miller's system of exclusive meal-feeding, it is probable that a portion, at least, of the saving in fodder is due to the less amount of work imposed on the digestive organs. In practice, however, considerations of profit come in to modify the conclusions just drawn. As a general rule, a given number of pounds of digestible matter can be had more cheaply in the form of coarse fod- der, such as hay, straw, etc., than in the more concentrated fodders, like the grains, which contains less indigestible mat- ter. Moreover, ruminating animals are adapted by nature to extract the nutritive matters from coarse fodder as com- pletely as possible, so that it is obvious that under some circumstances it may be more profitable to feed almost exclusively coarse fodder (in wintering stock, for example), while in other cases, e. g., fattening, where a rapid produc- tion is desired, the greater cost of concentrated fodders may be more than covered by the economy of digestive labor and the consequent saving of material which they cause. Pkoduction of Heat.— The continual chemical changes 230 MANUAL OF CATTLE-FEEDING. going on in the body, like similar changes outside the body, give rise to a liberation of heat. Indeed, all the force conveyed to the body by the food leaves it either as motion or heat, all the actions of the internal organs, all the molecular labor of the nervous and other tissues, etc., being finally converted into heat. It has been estimated by eminent authorities that, in man, of the total energy represented by the food, from four-fifths to five-sixths takes the form of heat. This production of heat, of course, implies a corresponding consumption of food-material, just as the production of heat in a stove implies the con- sumption of fuel ; so that it is evident that any change in the amount of heat set free has a direct effect on the de- mands of the body for food and on the results of feeding. Vital Heat. — The bodies of warm-blooded animals (birds and mammals) maintain a very constant temperature at all times, in spite of great variations in the temperature of their surroundings. The production of mtal heat, as it is called, by the oxidation of food-elements, and the losses of it to which the body is subject, are so balanced as to result in keeping the temperature of the body at from 95° to 104° F., a variation of more than a degree or two from the normal temperature of an animal indicating serious dis- turbance of the organism. This regulation of the vital heat appears to be effected in two ways : first, by variations in the loss, and second, by variations in the production. The chief sources of loss of heat by the body are : 1. Conduction and Ttadiation from the Skin. 2. Evaporation of Water from the Skin and Lungs. 3. Warming of the Ingesta (Food and Drink). These we will take up in tlieir order and consider how in each case the balance of the vital heat is kept up. MANUAL OF CATTLE-FEEDING. 231 Conduction and Radiation from the Skin. — This is one of the principal sources of loss of heat by the body, and also the one which is most susceptible to regulation. Henne- berg,^ in his respiration experiments on sheep, already cited, estimates that the total amount of heat produced by the animals experimented on was applied as follows : To warming the ingesta 4. per cent. " "• " inspired air 4.2 " ' ' evaporation of water 26.7 '* " supply loss by radiation, etc C5.1 " Experiments on man hav^e given very similar results. Plainly, the greater the amount of blood passing through the vessels of the skin, the more heat will be lost, while, on the other hand, a diminution in the current of blood will check the loss of heat. Kow when the skin is exposed to cold, as, for example, to cold air or to the water of a cold bath, the capillaries of the skin are contracted and the blood-vessels of the vis- cera expanded, thus diverting a portion of the blood from the former to the latter and sometimes causing a rise of temperature in the interior of the body. Conversely, under the influence of warmth the capillaries of the skin dilate, admitting more blood, and thus effecting a cooling of the latter. To this is to be added the loss of heat by the evaporation of the perspiration, to which atten- tion will be called on subsequent pages. In this manner the loss of heat from the surface of the body is regulated in accordance with the external tem- perature, but there are numerous experiments which show that under such circumstances the 'production of heat also varies, though we have but little knowledge of the * Neue Beitrage, etc., 1871, p. 227. 232 MANUAL OF CATTLE-FEEDING. means by wliicli these variations are effected. It Las been sliown by numerous observations on rabbits, guinea- pigs, and cats that, in warm-blooded animals, exposure to cold largely increases both the consumption of oxygen and the excretion of carbonic acid, thus showing a greater activity of the chemical processes in the body and pre- sumably an increased production of heat, while warmth, on the other hand, has the converse effect, diminishing the amount of chemical change in the body. The following selection from the results obtained by Theodor ^ in an extensive series of experiments on a cat will serve to illustrate these facts. Each experiment lasted six hours. Temperature. Deg. Cent. Carbonic acid excreted. G-rms. Oxygen taken up. Grms. Temperature. Deg. Cent. Carbonic acid excreted. Grms. Oxygen taken up. Grms. -5.5 19.83 17.48 -hl2.3 17.63 17.71 -3.0 18.42 18.26 + 16.3 15.73 14.74 +0.2 18.24 19.95 +20.1 14.34 12.78 -i-5.0 17.90 14.82 + 29.6 13.12 10.87 In some of these experiments considerable motion on the part of the animal took place, which may have influ- enced the result, and Yoit f therefore executed a series of similar experiments on a man. The man weighed about 156 lbs., and, after having been exposed for some time to the temperature whose effect was to be observed, passed six hours in the respiration apparatus fasting and in com- plete rest. In this time he excreted the following quanti- ties of carbonic acid and nitrogen : ♦ Zeit. f. Biologic, XIV., 51. f Ibid., XIV., 57. MANUAL OF CATTLE-FEEDING. 233 Temperature. Deg. Cent. Carbonic acid. Grms. Ureal nitrogen. Grms. Temperature. Deg. Cent. Carbonic acid. Grms. Ureal nitrogen. Grms. 4.4 210.7 206.0 192.0 155.1 158.3 4.23 4.05 4.20 3.81 4.00 23.7 24.2 26.7 30.0 164.8 166.5 160.0 170.6 3.40 6.5 3.34 9.0 3.97 14.3 16.2 The increased excretion of carbonic acid in the cold as compared with an ordinary temperature of 14° to 15° C. (about 60° F.) is as marked in these experiments as in the preceding ones, but above that temperature a slightly in- creased excretion was observed. The excretion of nitrogen is seen to vary in the same way, though to a small extent, indicating an increased protein consumption as a result of exposure to a low temperature. These results show plainly how great an influence the temperature of its surroundings may have on the amount of fodder required by animals, and confirm the conclusion drawn from many practical experiments, that it is desirable to protect animals from extreme cold. In conclusion, it should be said that the action of a low temperature of the surrounding medium appears to be, in the first place, on the nerves, and that only through them does it cause a greater activity of the chemical processes in the body and an increased production of heat. It has been shown by Pfliiger that when this action of the nerves is hindered, the activity of chemical change in the body is increased by heat and decreased by cold, just as many chemical processes outside the body are, and as is the case normally in cold-blooded animals. 234 MATs^UAL OB^ CATTLl>FKP:i)ING. Evaporation of Water. — An important regulator of the temperature of the body is the evaporation of water, especially from the skin. In the conversion of any liquid into vapor, a very con- siderable amount of heat is absorbed, and becomes late7it in the vapor. This absorption of heat during vaporization may be rendered evident to the senses by wetting the hand with some volatile liquid, such as alcohol or ether, and moving it through the air to hasten evaporation. In the same way, the evaporation of water from the skin, which is constantly going on, cools the latter ; and though the effect is less noticeable than with a more volatile liquid, on accoimt of the greater slowness of the evaporation, the total amount of heat thus abstracted from the body is very considerable, amounting, according to Henneberg (p. 231), in the case of sheep, to nearly 27 per cent, of the total loss of heat. The conversion of one gramme of water at the tempera- ture of the body into vapor of the same temperature requires 580 heat units, an amount equal to that produced by the combustion of 0.148 grammes of organic matter having the composition of starch, and corresponding to an excretion of 0.241 grammes of carbonic acid. In the ex- periments by Henneberg just mentioned, the average daily excretion of water from lungs and skin was 881.7 grammes, which, according to the above figures, required for its evaporation as much heat as would be produced by the combustion of 130.5 grannnes of starch, while the average amount of carbhydrates digested per day was 464.3 grammes. Consequently, if the loss of heat by evapora- tion was supplied by the combustion of these substances, about 28 per cent, of them was thus consumed. Such results as this, of which many might be cited, show MANUAL OF CATTLE-FEEJJIJSG. 235 US plainly both the importance of the process of evapora- tion as a regulator of the vital heat, and the great waste of fodder that may be caused by an undue increase in the perspiration. The regulation of the temperature of the body by the perspiration, especially the sensible perspiration (sweat), is too familiar to require more than a simple mention ; but the effect of increased perspiration in augmenting the ex- cretion of carbonic acid is of greater importance for our present purpose. This effect is shown in these same ex- periments by Ilenneberg. In the following table his results are arranged according to the amount of carbonic acid excreted. The numbers refer to the two animals taken tog-ether : Tempera- ture of stall. Deg. Cent. Hay fed. Grms. Water drunk. Grms. Carbonic acid excreted. Grms. Water evaporated. Grms. Urinary nitro- gen. Grms. 9.3 12.7 14.1 13.6 13.7 13.7 2,508 2,085 2,275 2,241 2,459 2,443 2,757 (?) 3,193 (?) 3,038 3,876 1,468 1,508 1,525 1,548 1,579 1,633 1,268 1,578 1,601 1,680 1,750 1,650 14.81 15.42 16.91 15.59 15.56 16.02 It is evident at once that in every case but the last an increased evaporation of water and an increased excretion of carbonic acid accompany each other ; but whether the latter is a result of the former can be determined only after the possible influence of all the other factors which influence the excretion of carbonic acid has been consid- 236 MANUAL OF CATTLE-FEEDING. ered. These are, in this case, the amount of food, the amount of water drunk, and the temperature. That the amount of food has an important influence on tlie amount of carbonic acid excreted is a well-estabKshed fact, and is well illustrated by a seventh experiment on the same two sheep, in which all food was withheld for a single day. The carbonic acid excretion sank at once to 837 grammes, or scarcely more than half that previously ob- served. In these six experiments, however, although the amount of fodder eaten varied somewhat, no connection can be traced between its amount and that of the carbonic acid. The same is true of the amount of water drunk, while the lowest temperature {i.e., the one which should cause the greatest activity of the oxidations in the body) coin- cides with the minimum of carbonic acid. We must therefore conclude that there is a connection between the carbonic acid excretion and the evaporation of water, and that an increased evaporation causes more material to be oxidized in the body, in order to make good the resulting loss of heat. Henneberg's experiments are the only ones which we yet possess on this important subject, but they suffice to show its practical importance and the desirability of fur- ther experiments in the same direction. A direct influence of the amount of water evaporated upon the protein consumption does not seem to be indi- cated by these experiments. Warming Ingesta. — A considerable quantity of heat (according to Henneberg, about 4 per cent.) is consumed in raising the food and drink of an animal to the temperature of its body. Of this amount, by far the larger part is used in warming the water of the ingesta, both on account MANUAL OF CATTLE-FEEDING. 237 of its large amount and because a greater quantity of heat is required to increase the tempqrature of a pound of water one degree than is sufficient to effect the same change in a poimd of any other substance. The effect of excessive drinking on the production of flesh and fat has ah-eady been mentioned in the two pre- ceding chapters, and there can be little doubt that a part, at least, of this effect is due to the demand for heat thus made on the system. The last line of the table on p. 235 affords an illustra- tion of the influence of the amount of water drunk on the excretion of carbonic acid. Although the quantity of water evaporated is less than in the two preceding cases, more carbonic acid is excreted, evidently on account of the considerably larger amount of water drunk. It is notice- able that the urinary nitrogen in this experiment is also more than in most of the others. Further examples of the influence of the quantity of water drunk upon the decomposition of matter in the organism might be given, but the few results which have as yet been reached in this direction, while they afford im- portant practical hints, are still so meagre that no very ex- tended conclusions can be based on them. Practical Conclusions.— In the foregoing pages we have seen that the production of heat makes large demands on the food supply of an animal, and that various circum- stances may influence the amount of heat produced and thus effect an economy or a waste of fodder. There re- mains to be considered the practical application of these facts to the feeding and care of cattle. Temperature of Stable. — It is evident that the warmer the air of the stable is kept the less heat the animals will lose by radiation, and consequently the greater wiU be the 238 MANUAL OF CATTLE-FEEDING. saving of fodder effected. If this were the only circum- stance to be considered, tliQ greatest economy would result from keeping the surroundings of the animal at the same temperature as its body, for then no heat would be lost by radiation. A high temperature, however, tends to increase the per- spiration, which, as we have learned, demands considerable heat for its evaporation ; so that the saving effected by the diminished radiation consequent on a high temperature may be more than counterbalanced by the loss due to the greater amount of perspiration evaporated. To this is to be added the fact that the animals are also led to drink more water, thus still further increasing, or tending to in- crease, the consumption both of protein and fat in the body. It thus becomes evident that the most favorable balance between these two opposing factors, and consequently the most economical production, may take place at a medium temperature, and this conclusion is one which accords with the general experience of farmers. That the least expenditure of material by the body takes place at a medium temperature is very clearly shown by Yoit's experiments, cited on p. 233. Finally, the question of profit comes in. Warming the stable in winter involves a certain amount of expense; leaving it cold also involves a certain amount of expense, viz., the cost of the excess of fodder required by the ani- mals. It is a question to be settled by the circumstances of each particular case which method of procedure is, on the whole, more profitable. Amount of Drbik. — As already pointed out, excessive drinking tends to increase the consumption of matter in the animal body, and thus to decrease the profits of the MANUAL OF OATTLE-FEEDING. 239 feeding. It therefore becomes the interest of tlie feeder to restrict the amount of water drunk by his animals to that required for health. This is estimated by Wolff at four pounds per pound of dry matter of the fodder for cattle,, and two pounds for sheep, this amount including that present in the fodder. The more watery the fodder the less drink is necessary. Naturally, the amount of water drunk will, in most cases, be left to the instinct of the animal, and regulated only by avoidance of those conditions which, like too large rations of salt, too high temperature of the stable, etc., in- crease the desire of the animals to drink. Finally, there is no doubt that it would be advantageous, when practicable, to supply animals with water warmed at least somewhat above the freezing temperature, since it would seem that at least one chief object of the increased protein and fat consumption caused by excessive drinking is to produce heat to warm the water to the temperature of the body. Still more is it desirable, in the wintering of stock, not to compel them to satisfy their thirst with snow or ice, since not only must these be warmed, but they must be melted^ and the conversion of one pound of ice at 32° F. into water of the same temperature requires somewhat less than twice the amount of heat needed to warm one pound of water from 32° to the temperature of the body. All this heat comes directly from the combustion of tissue, and is just so much subtracted from the net results of feeding, and consequently from the feeder's pocket. Cooking Fodder. —A portion of the advantage frequently claimed to result from cooking and steaming fodder un- doubtedly arises from the fact that the fodder is eaten while still warm, and that thus a certain amount of the sub- 240 MANUAL OF CATTLE-FEEDING. stance of the animal, which would otherwise be burned in warming the food, is rendered available for other purposes. This fact, in connection with the increased palatability of the fodder and the consequently greater consumption of it, probably explains the favorable results frequently ob- tained by means of this practice, and at the same time renders it evident that its profitableness must depend on circumstances. Under some conditions, the gain thus effected might repay the expense, while imder other con- ditions it might be more economical to let the cattle warm their own food. Production of Chemical Changes. — The food being, as already explained, the means by which supplies of force are introduced into the body, it is evident that any change taking place in the constituents of the food before they become part of the body by which any of the force which they contain is liberated, involves an equivalent loss to the organism. It is as if the fuel which is to drive the engine were partially burned before being put under the boiler. Such changes actually take place in the food to some ex- tent during digestion. For example, we have all along assumed that the carbhydrates yield grape-sugar in the alimentary canal, and all calculations of rations are based on that assumption. In the main it is probably correct ; but it is kno^Ti that portions of these bodies suffer still farther decomposition and yield lactic acid. In this pro- cess some of the latent force of the carbhydrates appears as heat, and the resulting lactic acid and other products are less valuable to the body by just the amount of force thus liberated. It was stated on page T)-!-, that many good authorities con- sider that the digestion of cellulose consists essentially in MANUAL OF CATTLE-FEEDING. 241 a kind of fermentation. Little is known of this process, but it is not improbable that the small quantities of marsh- gas and hydrogen exhaled bj ruminants have their source in it, and this fact indicates that a considerable part of the latent energy of the cellulose is liberated during its diges- tion. This raises the question whether the various carbhy- drates are equally valuable as nutrients — a question which has, as yet, received scarcely any attention. Their equiva- lency has been assumed and made the basis of the calculation of rations, simply because, in the lack of all evidence, this was the only practicable method. It is quite probable that this assumption does not involve any very great error, except, perhaps, in the case of cellulose ; but the actual comparative value of these substances can be determined only when we know, first ^ how much latent energy each 'contains, and, second^ how much of this energy is liberated dm'ing digestion. This is, of course, equally true of the other classes of nutrients ; * but the study of this subject can hardly be said to have begun, and the only object of mentioning it here is to show how provisional are our present methods of estimating the value of fodders, and to guard the reader against the error of considering them final and conclusive. They are of great value and have rendered very important service ; it is certain that they are not grossly erroneous. At the same time, no good and much harm may come from an unintelligent overestimate of their accuracy and value. The so-called synthetic chemical actions (that is, f orma- * The few results which have been obtained on the albuminoids will be mentioned in another connection. They indicate that the vegetable and animal albuminoids are practically equivalent. 11 242 MANUAL OF CATILE-FEEDING. tions of complex siil)staiices from simpler ones), of which many have been shown to take place in the body, also de- mand a supply of force for their performance. Thus the production of the true " contractile substance " of the muscles (see p. 224), if such a substance exists, from pro- tein and non-nitrogenous matter, must absorb and render latent large amounts of force coming from the simultaneous oxidation of other materials. Such processes, however, have no significance to the feeder, since the force thus rendered latent is not with- drawn from the body, but is set free again in it when the complex substance is decomposed. Influence of Stimulants. — The influence of stimulants upon the chemical processes in the body has been but little investigated. Yoit's experiments on cofPee * seem to indicate that this substance, at least, has practically no effect upon the pro-' tein consumption in the dog. On the other hand, it would seem that the oxidation of non-nitrogenous matters maybe considerably affected by nervous influences, such as cold, stimulation of the skin, light, sound, etc. The fact that the excretion of carbonic acid is less during sleep also points in the same direction. There appear to be no experiments on farm animals 'ouching this point, but we may safely conclude from the ^cts known concerning other animals, as well as from practical experience, that nervous excitement, produced by rough treatment, noise, etc., is unfavorable to the best results of feeding. * " Untersuchungen iiber den Einfluss des Kochsalzes, Kaffee's, etc., auf den Stoffwechsel." PAET II. THE FEEDING-STUFFS. CHAPTEE I. DIGESTIBILITY. A STiBSTAiTCE IS Said to be digestible if, when eaten, it can either be taken up directly by the absorbent vessels of the stomach and intestines, or is capable of being altered by the digestive fluids into substances which can be thus resorbed. The pure nutrients (except, perhaps, cellulose) may be considered to be wholly digestible, thus justifying their name, but as they occur in feeding-stuffs various circumstances conspire to prevent their entire digestion. In the first place, as has already been more than once pointed out, our methods of fodder analysis are very im- perfect, and serve only to divide the substances contained in the fodder into groups of more or less similar matters. All the nitrogenous matters are — or have hitherto been — included under the albuminoids, all the substances soluble in ether under fat, etc., while the nitrogen-free extract, being determined by difference, includes everything not 244 MANUAL OF CATTLE-FEEDING. belonging to the other four dasses. It is evident that, be- sides real nutrients, each of these groups of substances may include many things which are wholly indigestible, and hence that, although pure protein, for example, may be wholly digestible, the "crude protein" of hay or straw may be only partially digestible, as is actually the case. Furthermore, a substance which of itself is entirely di- gestible may be so enclosed in indigestible matters as largely or entirely to escape the action of the digestive fluids. For example, seeds which are swallowed whole gener- ally escape digestion, in spite of the fact that they consist largely of digestible matters, because their hard outer coat- ings shut np the latter in an impervious shell. Similarly, if the walls of a single cell are so hard and woody as to be nnacted on by the juices of the alimentary canal, the con- tents of the cell may pass through the animal without being digested. Finally, the relative quantities of the several nutrients in the fodder of an animal have a mutual influence on the amount of each digested. Tims, if a fodder be made over- rich in starch, the digestibility of the albuminoids is de- creased, and, at the same time, a poi'tion of the starch escapes digestion. All these considerations render it obvious that a simple analysis is not sufficient to determine the value of a feed- ing-stuff, but that the digestibility of its constituents must be taken into account, either by direct experiment or by reference to the results of previous experiments. In this chapter we shall consider such general principles as experiment has established regarding the digestibility, first, of coarse fodder, and second, of the concentrated bye-fodders, under the influence of various conditions, and MANUAL OF CATTLE-FEEDING. 245 in the following ones take np in detail the properties and digestibility of the more important feeding-stnffs. In this connection it is important to distingnish between digestibilitij and ease of digestion. By the digestibility of a feeding-stnff, or any ingredient of it, we mean the extent to which it is digested nnder ordinary conditions. If, in a digestion experiment, one- half of the crude protein of a certain feeding-stuff is di- gested, we express the digestibility of that nutrient by the number 50 -that is, 50 per cent, of it was digested. If the digestibility of the crude fibre of a certain sample of hay is said to be 40, it means that 40 per cent, of it was digested. These numbers, expressing the percentage of the several nuti-ients of a fodder which is digestible, are called digestion coefficients. In general, a high digestibility will naturally accompany easy digestibility, but this may not always be the case, and the two conceptions are entirely distinct. § 1. Digestibility of the Nutrients op Coarse Fodder. By the term " coarse fodder " we designate the various kinds of grass, hay, and straw, corn-fodder, stover, and, in short, all kinds of forage, whether fed green or dry. Coarse fodder commonly consists of the stalks and leaves of the plants, and is rich in woody fibre. Under ordi- nary circumstances it forms the bulk of the fodder of farm-animals, with the exception of the hog. In this section we shall consider the digestibility of the several nutrients of coarse fodder when this is fed exclu- sively, taking up subsequently the influence of the quality of the fodder and of the presence of concentrated bye-fod- ders on the digestibility of the ration. 946 MANUAL OF CATTLE-FEEDING. The Weende Experiments. — The foundations of our knowledge of the digestibility of feeding-stuffs were laid by the labors of Ilenneberg & Stohmann, at the Weende Experiment Station near Guttingen. Their experiments began in the year 1858, and in 1860 they published their first results, under the title '' Be it rage zur BegriXndung einer rationellen Filtterung der Wiedei'hduer^'''' of which a second volume appeared in 1863-64. Further experi- ments were made in 1863-64 by G. Kiihn, H. Schulze and Aronstein," under Ilenneberg's direction, and in 1865 by Henneberg.f All these experiments were made on mature oxen, and gave results regarding the digestibility of feeding-stuffs, particularly of coarse fodder, which subsequent investiga- tions on these and other animals have served only to con- firm, while they still form tlie basis of our feeding stand- ards for oxen. To these same investigators is likewise due the credit of developing and perfecting methods of experiment adapted to such researches, and which can hardly be said to have existed before, so that the Weende experiments may be considered to mark the beginning of a new era in the science of feeding. Since their publication innumerable feeding experiments has^e been made, involving determinations of the digesti- bility of various feeding-stuffs, the results of which, in all important points, have been the same as those reached in Weende. It is far beyond the scope of this work to give even a partial account of these experiments, and we must content ourselves with selecting a few results to illustrate each point as it is brought up. ♦ Jour, f . LandwirthBchaft, 1865, p. 283 ; 1866, p. 269, and 1867, p. 1 fNeue Beitrage, etc., Heft 1, p. 287. MANUAL OF CATTLE-FEEDING. 247 Crude Fibre Digestible. — As has been already stated in a preceding chapter, a portion of tlie crude fibre of coarse fodders is digestible. This fact is so well ascer- tained, and has been so uniformly observed, that no special proofs of it need be brought forward here. The amount digested varies, according to the quality of the fodder and other circumstances, from 25 per cent, to as high as 70 per cent, of the total quantity. The ruminants, in particular, have the power of digest- ing large amounts of crude fibre, a power due, doubtless, to the great extent of their alimentary canal and the length of time during which the food remains in it. They are hence especially adapted to the consumption of coarse fodder, such as hay and straw, and can extract from it considerable quantities of nutrients, while the horse stands considerably below them in this respect, and the hog seems, like the carnivorous animals and man, to be able to digest only young and tender fibre, such as is found in roots and in young and juicy green fodder. The Digested Portion is Cellulose. — The "crude fibre " obtained in analysis is a mixture of cellulose and " lignin," but the digested portion has been shown to con- sist of cellulose only, which has exactly the composition of starch (p. 39) and therefore is assumed to have the same nutritive value as the latter.* This fact has been deduced by a comparison of the ele- mentary composition of the crude fibre of the fodder and of the excrement, as in the following example — an experi- ment made at Weende in 1860-61. The fodder was wheat-straw, and 52 per cent, of its crude fibre was digested, while 48 per cent, was found in * Compare page 241, 248 MANUAL OF CATTLE-FEEDING. the excrement. The original crude fibre of the fodder and that of the excrement had the following composition re- spectively : Excrement. Carbon . . Hydrogen Oxygen. . . The following calculation gives us the composition of the digested portion : Carbon. Hydrogen. Oxygen. In 100 parts of crude fibre of fodder. . . 45.4 6.3 48.3 " 48 " '' " dung.... 23.09 3.26 21 65 DifEerence = 52 parts of disrested crude fibre 22.31 42.9 3.04 5.7 26.65 In 100 parts of digested crude fibre 51.4 " " cellulose 44.4 6.2 49.4 The above numbers are simply intended to illustrate the method of calculation ; in other and later experiments a much closer correspondence with theory has been obtained. For example, the average of eleven experiments made in Weende hi 1863-64, on various khids of coarse fodder, and with every precaution, was the following, which corresponds as closely as can be expected in such experiments wdth the composition of pure cellulose : MANUAL OF CATTLE-FEEDING. 249 Carbon . . . Hydrogen. Oxygen. . . Pure cellulose. 44.4 6.2 49.4 In these exp,eriments the true cellulose in fodder and excrements was determined by a method proposed by F. Schulze, and from the data thus obtained the absolute amounts of cellulose digested in each experiment were cal- culated. The results were practically identical, as the fol- lowing table shows, with the amount of crude fibre digested, thus furnishing another proof that the latter con- sisted of cellulose. No. of Experiment. Crude fibre digested. Lbs. Cellulose digested. Lbs. Difference. Lbs. 1 2.01 1.91 3.92 4.63 4.81 4 37 4 38 2.12 2.16 3.87 4.47 4.55 4.02 4.13 -f-0.11 -1-0 25 2 4 ., —0 05 5 -0 16 6 -0 26 7 -0 35 8 „ . . —0.25 By no means the whole of the cellulose of coarse fodder is digested, biit its percentage digestibility is consider- ably greater than that of the " crude fibre." Nitrogen-free Extract. — While a part of the crude fibre is always digested, especially by ruminants, a part of the so-called nitrogen-free extract, on the other hand, is 11* 250 MANUAL OF CATTLE-FEEDING. not digested, or is at least, even if present in an easily soluble form, not resorbed, but excreted with the dung. Compensation. — It is a noteworthy fact that a com- pensation takes place between the digested portion of the crude fibre and the undigested portion of the nitrogen-free extract. That is to say, these two quantities are always nearly equal, so that the amount of the nitrogen-free ex- tract found by analysis is an approximate measure of the di- gestibility of the total non-nitrogenous matters of the fodder y edcdusiwe of fat * (^. ^., crude fibre + nitrogen-free extract). This fact, however, is only true in a general way and on the average. In particular cases considerable variations are not infrequent, so that the quantity of non-nitrogenous substance digested varies from somethnes 120 per cent, to as low as 80 per cent., or even less, of the amount of nitrogen-free extract found by analysis, the theoretical number being, of course, 100 per cent. It has been observed in several cases that the exactness of the compensation between the digested crude fibre and the undigested extract is influenced by the digestibility of the crude fibre. Thus Stohmann,'!' who was the first to call attention to this fact, obtained in experiments on goats, the following figures for meadow hay : Digestible fibre and extract in per cent, of nitrogen-free extract. . . Digestibility of crude fibre Hay No. 1. 97 63.6 Hay No. 2. 86 58.0 Hay Hay No. 3. No. 3. (Another animal.) 82 51.0 73 44.6 * The fat is sometimes included. Its amount is so small as to make little difference practically. f "Biologische Studien," 1 Heft, p. 72. MANUAL OF CATTLE-FEEDING. 251 Here it is evident that with increasing indigestibility of the crude fibre the amount of digestible non-nitrogenous matters falls more and more below the quantity of nitro- gen-free extract, while only in the first case are the two approximately equal. Other investigators have confirmed this result, and it has also been shown that the decrease in the digestibility of the total non-nitrogenous matter is, at least in some cases, less rapid than that in the digestibility of the crude fibre. The younger and more tender a fodder is, the smaller is generally its percentage of crude fibre, and the greater is the digestibility of the latter. As a consequence, the whole amount of non-nitrogenous matters digested from such a fodder is generally larger, in comparison with the quantity of nitrogen-free extract, than is the case with one cut at a more advanced period of growth. As an example of this may be mentioned some experi- ments on sheep made by Wolff ^ at Hohenheim, in which the animals were fed with green clover cut at four differ- ent periods of growth, 'No. 1 being the youngest and No. 4 the oldest. The first line {a.) of the table gives the per- centage obtained by dividing the quantity of non-nitroge- nous matter actually digested by the amount of nitrogen- free extract found by analysis, and hence shows how much tlie amount actually digested varied from the theoretical amount. The second line (5.) gives the percentage of the crude fibre which was digested. No. 1. No. 2. No. 3. No. 4. (6.) 111.9 60.0 105.5 53.0 101.8 49.6 88.5 38.8 252 MANUAL OF CATTLE-FEEDING. In No. 1 and No. 2, whose crude fibre was easily digest- ible, the actual amount of non-nitrogenous nutrients di- gested was greater tlian that calculated ; in Xo. 3 the two were nearly equal ; in No. 4, where the crude fibre was less digestible, it was only 88.5 per cent, of the theoretical amount. It is obvious, from such results as these, that while the compensation between digested crude fibre and undigested nitrogen-free extract may be an aid in forming an estimate of the digestibility of a fodder, it is not sufiiciently close to serve as the basis of exact calculations. Recent experiments on the horse, to which reference will be made in subsequent pages, have shown that crude fibre is less digestible by this animal than by ruminants, and that consequently this compensation only takes place in very young and tender fodder. Composition of Digestible Portion of Nitrogen-free Extract. — It has been shown, by essentially the same method as that applied to crude fibre, that the digestible portion of the nitrogen-free extract has very nearly the composition of starch. We may therefore assume that all the digestible non-ni^ trogenous substances of the fodder, with the exception of the fat, are, like starch itself, converted into sugar or sugar- like substances, and as such are resorbed and taken into the circulation. Further exceptions to this rule are the small quantities of organic acids either contained ready formed in the fod- der or produced during digestion from the carbhydrates. The quantity of these, however, is very small, and we can,* in general, regard all the digestible non-nitrogenous *With the reservations made ou p. 1S4. MANUAL OF CATTLE-FEEDING. 253 matter of the fodder, except the fat, as composed of carb- hjdrates and as liaving the same functions in nutrition as sugar and starch have been proved to have in the experi- ments which have been detailed in Part I. Composition of Undigested Nitrogen-free Extract. — The part of the nitrogen-free extract which remains undigested is a mixture of various substances richer in carbon than the carbhydrates and having, as a wliole, nearly the percentage composition of lignin, as given on p. 39. It is therefore a matter of comparative indifference in fodder analyses, whether the lignin dissolves in the acid and alkaline liquids used to isolate the cellulose or remains with the latter as incrusting substance. In one case it ap- pears in the results of analyses as part of the nitrogen-free extract, in the other, as crude fibre ; in both cases it reap- pears in the excrements and leaves the total quantity and quality of the digested nutrients the same, and the only effect of a variation of this sort would be on the compen- sation between the undigested extract and the digested fibre. The Aqueous Extract. — From the numerous experi- ments executed in Weende on oxen and sheep, the law has been deduced that the total quantity of solid matter that can be extracted from a fodder by boiling water, i. e., the aqueous extract, is a measure of the digestible portion of the nitrogen-free extract. In single cases, however, con- siderable variations from the rule were observed on both sides of the average, amounting to as much as 14 per cent. This method of judging of the quality of coarse fodder has not found any general application, for the reason that no necessary connection exists between the digestible ni- 254 MANUAL OF CATTLE-FEEDING. trogen-free extract and the amount of substances soluble in water, since the latter includes not only non-nitrogenous matters but also larger or smaller quantities of protein and ash. The rule is to be considered as, at best, a purely empiri- cal one, which, to be sure, has some value for practical purposes, since in general the digestibility of a coarse or green fodder is greater the more solid matter can be ex- tracted from it by boiling water, but to which no scientific value can be attached. Crude Fat. — That the crude fat, or rather the ether extract, of the coarse fodders is a mixture of the most various substances, some of which are digestible and some indigestible, has been already explained. The chlorophyll, or green coloring matter of plants, is soluble in ether, but seems to be entirely indigestible, and the wax-like sub- stances most probably belong to the same category. It is therefore to be expected that the digestibility of the crude fat will be very different according to the kind and quality of the fodder. It is always greater in young and tender plants than in older ones, and it has also been ob- served that the crude fat of clover hay and of the straw of the legumes is generally more digestible than of that of meadow hay and the straw of the cereals. Crude Protein. — The digestibility of crude protein in the various kinds of coarse fodder is subject to greater variations than that of almost any other constituent. Of the protein in clover hay and meadow hay, e.g.,2i quantity varying, according to circumstances, from 35 per cent, to 75 per cent, of the total amount is digested. Generally the protein is more easily and completely digested the greater the percentage of it contained in the fodder, i. e., the narrower the nutritive ratio. At the same time, the MANUAL OF CATTLE-FEEDING. 255 quantity and quality of the crude fibre has an influence on its digestibility. Formulae for Digestibility of Protein. — As we have seen, the digestibility of the non-nitrogenous matters of a coarse fodder, with the exception of the small quantity of fat which it contains, can be estimated from, the results of analysis with sufficient accuracy for practical purposes, al- though not with scientific exactness. Unfortunately, we have no such simple means of esti- mating the digestibility of the crude protein, although the attempt has more than once been made to supply one in the shape of a formula which should enable us to deter- mine the digestibility of the crude protein of a fodder or of a ration by calculations based on its composition. These formulae are, of course, all empirical, being founded on the results of as many feeding experiments as possible. In ^dew of the importance of protein in nutrition, and the great variability which experiment has shown to exist in its digestibility, the advantages to be derived from a correct formula of this sort are manifest. [N^evertheless, none of the various fornmlae which have been proposed have met with much favor, and it seems to be the opinion of the best authorities that it is yet too soon to attempt their formation. All these formulae aim to express the influence of the chemical covipositlon of the fodder or ration on the diges- tibility of its protein — an influence which, though an im- portant one, is by no means the only factor involved. As regards coarse fodder alone, they offer little advantage over the intelligent use of " digestion coefficients," and the less since the results obtained by their aid sometimes vary widely from the truth. In the case of a ration including considerable concentrated fodder, they seem to yield more 256 MANUAL OF CATTLE-FEEDING. exact results, and may prove of value to test the corre- spondence of a ration with the feeding standard, though they would be of but little use in compounding it. For this purpose, Stohmann's formula ^ is probably the best. It is the following : in which j>' represents the digestible protein, p the total " crude protein," and s the total non-nitrogenous matters of the ration, including fat. This formula makes the digestibility of the protein de- pend on the relative amounts of nitrogenous and non- nitrogenous nutrients, ignoring the influence of the amount of crude fibre. For this reason, it appears to give better results when applied to rations containing much concen- trated fodder than when used for those composed exclu- sively of coarse fodder. Finally, it must never be forgotten that these formulae are entirely different fi*om those of the mathematician. They do not, like those, express necessary truths, nor are they deduced from any well recognized natural law. They are inductions, and depend for their value on the number and accuracy of the observations upon which they are based. They may be of much value, but we must beware of trusting them too implicitly. In regard to the digestibility of the protein of the coarse fodders, much that is of importance and can find application in practice has already been ascertained. On the more important kinds of coarse fodder large numbers of digestion experiments have been made, and we are able to give, as the results of these, coeflScients expressing the * Landw. Versuchs-Stationen, XI., 401. MANUAL OF CATTLE-FEEDING. 257 average digestibility of the protein and tlie other ingre- dients of fodders as well as the range of variation ob- served. (See table in Appendix.) Some of these num- bers are the average of more than fifty experiments, and therefore may be regarded as expressing, with con- siderable accuracy, the average digestibility of these sub- stances. Others are the result of only a few trials, and hence are more liable to correction by the results of new experiments. Furthermore, we are able to judge, to some extent, of the digestibility of the protein in coarse fodder of different qualities and cut in various stages of growth, and of its digestibility by different kinds of animals, and have acquired some knowledge of the influence exerted upon it by the addition of concentrated feeding-stuffs to the ra- tion. These points will be considered in the following sections. Non-Protein. — Besides protein, coarse fodder, especially when cut young, is likely to contain a greater or less quantity of amides and other nitrogenous substances which we may, for convenience, designate as non-protein. These, so far as investigated, are soluble substances, and there is little doubt that they are easily and completely di- gested. In all the statements of the previous paragraph reference was had to " crude protein," that is, to the total nitro- genous matters of the fodder. If account be taken of the amount of "non-protein" present, the digestibility of the true protein would, of course, be less ; but how much less future investigations must show. Ash. — Phosjylioric Acid. — When ruminants are fed exclusively on coarse fodder, only traces of phosphoric :acid are found in their urine. Only so much of the plios- phoric acid of the fodder seems to be resorbed as is neces 258 MANUAL OF CATTLE-FEEDING. sary for whatever formation of new tissue or of milk may take place ; all the rest is excreted in the dung. On the other hand, the urine of the ruminants is, like that of the carnivora, very rich in phosphoric acid (20 to 45 per cent, of the ash) when the animals are fed exclusively on milk, or when full-grown animals are deprived of food for several days, so that they finally subsist upon their own flesh and fat. When calves and lambs are fed large quan- tities of grain, a greater or less quantity of phosphoric acid always appears in the urine. The method of excretion of the phosphoric acid of the fodder therefore varies with the kind of feeding. Accord- ing to Liebig, phosphoric acid is absent from the mine of herbivora because this liquid is usually alkaline and be- cause the fodder usually contains much lime. Phosphate of lime is insoluble in alkaline fluids, and therefore phos- phoric acid only appears in the urine when more is con- tained in the foddei* than is sufficient to unite with the lime. Presence of magnesia, on the other hand, as Bert- ram ^ has recently shown, does not hinder the appearance of phosphoric acid in the urine, even though the latter be alkaline. AVhen this takes place the urine is found to be free from lime. Other Ash Ingredients. — Of the alkalies of the fodder 95 to 97 per cent., of the magnesia 20 to 30 per cent., of the lime only 2 to 5 per cent, and sometimes none, and of the sulphuric acid and chlorine, nearly the whole quantity, is excreted in the urine. The remainder of the above- named ash ingredients, so far as they are not held back and used in the body or in the production of milk, is found, along with the whole of the silica, in the dung. ♦ Biedermann's Central- Blatt, Jahrg, 8, p. 108. MANUAL OF CATTLE- FEEDING. 259 § 2. clbcumstances afpectina the digestibility op coarse Fodder. Influence of the Quantity of Fodder. — Feeding vary- ing quantities per day and liead of the same coarse fodder does not alter the percentage digestibility of the various nutrients. E. g., if on a certain ration of hay an animal digests 76 per cent, of the total quantity of crude protein, and the amount of the ration be increased by one-third or one-fourth, 76 per cent, of the protein will still be digested, and the absolute quantity will accordingly be one-third or one-fourth greater. This fact is shown by a number of the Weende experi- ments in which varying quantities of meadow hay or clover hay were fed to oxen, and also in experiments by Wolff,* at Hohenlieim, on sheep fed on clover-hay. In the latter experiments the following results were ob- tained : Fodder per day. Pounds. Digested. Protein. Per cent. Fat. Per cent. Crude fibre. Per cent. Nitrogen- fi-ee extract. Per cent. 3 59 61 60 55 56 54 51 54 51 63 2 64 2 63 Some later experiments by the same investigator f have shown that the same fact is true of the digestibility of lucerne hay by sheep and likewise by the horse. The re- sults on the latter animal were as follows : * " Die Versuchs-Station Hohenheim," p. 75. f Landw. Versuchs-Stationen, XXL , 20. 260 MANUAL OF CATTLE-FEEBING. Fodder per day. Pounds. DiGESTKO. Protein. Per cent. Fat. Per cent. Crude fibre. Per cent. Nitrogen- free extract. Per cent. 17 6 74 73 77 • * 33 37 43 70 22 .... 71 26 4. . 72 A point to be considered is that all the observations hitherto made have been only on meadow hay, clover, and lucerne, of good or medium quality ; but the same fact is, in all probability, true also for the more indigestible fodders, such as straw, chaff, etc. This constancy is very important, and facilitates greatly the calculation of rations for the various purposes of agri- cultural practice. Effect of Drying. — All the nutrients of dry coarse fod- der are digested and resorbed to the same extent as when it is fed green. Of the numerous experiments on this point, the follow- ing, by Weiske,"^ may serve as an example. They were made on two sheep, with lucerne, which was first fed green, and then after having been carefully dried without loss. The averages of the results on both animals were : Digested. Protein. Per cent. Crude fibre. Per cent. Fat. Per cent. Nitrogen- free extract. Per cent. Green 79 78 33 34 38 50 68 Dry 65 * Wolfif : " Die ErnJihrung der Landw. Nutzthiere," p. 97. MANUAL OF CATTLE-FEEDING 261 "With the exception of the fat, whose digestibilit}^, as we have seen, cannot be determined very accurate! j, the seve- ral nutrients were equally well digested in the two cases. This result, which has ])een fully confirmed by many other experiments, stands in apparent contradiction to the general experience of farmers. It must be remembered, however, that it is only true when the green fodder and the hay are otherwise of exactly the same quality; when both are cut at the same time and from the same field, and when none of the leaves or other tender and especially nutritious parts are lost during the preparation of the hay. These conditions are never completely reached in prac- tice, especially in the making of clover or lucerne hay, and for this reason, and also because green fodder is commonly used at an earlier stage of growth than that which is con- verted into hay, a greater nutritive effect is generally ob- served with green fodder. For the present we may pass over the question whether the large quantity of water which milking animals con- sume in green fodder exercises any considerable influence on the amount of milk produced, but the digestibility of the organic constituents of a fodder is in no way altered by simple drying in the air, provided it is executed with- out loss of parts of the plants. On \he other hand, the ordinary method of making hay involves a considerable loss of leaves, etc., and the product suffers not only in its quality, as shown by chemical analy- sis, but in its digestibility as well. For example, in some experiments at Hohenheim, by Wolff, Funke, and Kellner,"^ the loss involved in the prep- * Landw. Versuchs-Stationen, XXI. , 435. 262 MANUAL OF CATTLE-FEEDING. aration of lucerne hay amounted to 7.13 per cent, of tlie dry matter, and the composition and digestibility of the resulting product, as compared with that obtained by dry- ing the same material without loss, were as follows : Composition. DlGBSTrBIUTT. Dried without loss. Hay. Dried without loRS. Hay. Protein 17.00 31.81 43.80 7.39 14.94 83.90 44.22 6.94 71 48 29 67 Crude fibre 45 Nitrogen-free extract ) Fat j Ash 62 23 100.00 100.00 Effect of Storing. — The storing of fodder for a long time, even when all necessary precautions, such as a dry and airy location, etc., are observed, may decrease both its digestibility and palatability. At least, this conclusion can be drawn from some experi- ments executed in Hohenheim.* Of the crude protein of a sample of rowen, 62 per cent, w^as found digestible directly after the harvest, while three months later 56 per cent., and in the following spring 54 per cent., of the total quantity was digested by the same animals. The digesti- bility of the crude fibre also decreased somewhat, while that of the other nutrients remained about the same. A similar fact was observed by Ilofmeisterf in regard to clover hay, and essentially the same results were also ob- tained in later experiments in Ilohenheim. ♦Landw. Jahrbucher, IL, 282. f Landw. Versuchs-Stationen, XVL, 353. MANUAL OF CATTLE-FEEDING. 263 In all the Holienlieim experiments, the chemical compo- sition of the fodder remained substantially unchanged, and the deterioration showed itself in a diminished digesti- bility. Whether, however, the smaller nutritive value of hay and straw kept over winter, which is often observed in practice, even when the hay has apparently kept excellent- ly, is caused by an essential alteration in the digestibility of the fodder, or is to be sought chiefly in the mechanical loss of the more nutritious parts, which always takes place to some extent, and in decreased palatability, must be left to future researches to decide. Period of Gro^vth. — Early cut forage is not only supe- rior, other things being equal, to late cut, as regards its chemical composition, but it excells it in digestibility as well. This fact is established by abundance of experimental evidence. In some experiments by G. Kiilin,* oxen were fed with clover hay cut from the same field at three different tunes, viz. : I. Cut May 20, just before flowering. n. " June 7, in full bloom. III. " " 20, end of flowering. The composition and digestibility of the water-free sub- stance of these hays were the following : Composition. Protein. Per cent. Crude fibre. Per cent. Fat. Per cent. Nitrogen- free extract. Per cent. Ash. Per cent. I 19.56 16.31 13.19 25.30 28.11 28.80 2.25 2.87 2.86 45.52 44.95 48.37 10 10 II 7.76 6 78 Ill * Wolff: •' Ernahrung Landw. Nutzthiere," p. 106. 264 MANUAL OF CATTLE-FEEDING. Digestibility. I.. II. Ill Protein. Per cent. Grade fibre. Per cent. Fat. Per cent. Niti-ogen- free extract. Per Oent. 76 65 59 51 47 40 58 64 60 70 68 66 Ash. Per cent. In experiments made at Ilohenlieim on clover cut at four stages of growtli and fed to sheep, a similar decrease of tlie digestibility with increasing age was observed, that of the protein falling from 75 to 59, and that of the crude- fibre from 60 to 39. Many other similar experiments might be cited. Another circumstance which increases the feeding value of early cut forage is the fact that it is not only more digestible, but contains a much larger percentage of crude protein than is found in that cut later. The difference in the actual quantity of protein digested is thus larger in a two-fold ratio in early cut fodder. Thus, in the above- mentioned experiments by G. Klihn, the quantity of pro- tein actually digested amounted, in the first case (I.), to 13.9 per cent, of the total dry matter of the fodder ; in the last case (HI.) to only 7.8 per cent. These facts make it evident that the same kind of 'coarse fodder may differ greatly in its nutritive effect, according to the circumstances under which it is grown and har- vested. In considering these results, however, it is to be remem- bered that, as regards protein, the coefficients express the digestibility of the total nitrogenous matters, both albumi- MANUAL OF CATTLE-FEEDING. 265 noids and non-albuminoids. As we liave seen, recent in- vestigations have revealed the presence of large amounts of "non-protein " in coarse fodder, especially in the earlier stages of its growth. This non-protein is, in all proba-- bility, entirely digestible, and it is easily to be seen that its presence might affect the correctness of the above re- sults. The only experiments touching this point are a few by Wolff * on sheep and on a horse, with hay cut from the same field in two different years. These gave the fol- lowing digestion coefficients, a for total nitrogenous matter, h for true protein : Fodder cut. Sheep. HOBSE. a. b. a. b. April 24, 1874 Mavis, " 79.1 71.1 69.1 73.3 72.1 55.5 73.3 64.3 64.2 59.1 66.7 51.9 68.8 66.1 61.8 .... June 10, " May 14, 1877 June 9, *' 52.1 59 6 " 26, " 58 7 These figures are somewhat conflicting as regards the digestibility of the true protein in fodder cut at different times, and it must be left for future investigations to de- cide how far the results which have been obtained for the total nitrogenous matter of coarse fodders are true of their actual protein. Methods of Preparing. — While the various methods ♦ Land w. Jahrbiicher, VII. , I. Supplement, p. 263. 13 266 MANUAL OF CATTLE-FEEDING. of preparing fodder for animals, such as steaming, ensi- lage, etc., may be accompanied by practical advantages, all the experiments hitherto executed show that the diges- tibility is not sensibly increased thereby. Thus, in the experiments executed in 1862, at the Dahme Experiment Station, by Hellriegel & Lucanus,* it was found that the digestibility of rye-straw by sheep was not increased either by fermenting or cooking it. Experiments in Proskau, by Funke, gave the same re- sults regarding the digestibility of the total dry matter and the cellulose of a mixed ration fed to milk cows. Indeed, recent experiments at Poppelsdorf f showed a decreased digestibility of hay as a result of steaming. A rather coarse hay was fed to oxen, first dry, then steamed, and finally moistened with as much water as it took up when steamed. The following were the results : DiOKSTIBILITT. Total organic matter. Per cent. Protein. Per cent. Fat. Per cent. Crude fibre. Per cent. Nitrogen- free extract. Per cent. Dry 58 56 54 46 30 39 39 41 38 59 58 54 60 Steamed Moistened 59 57 Steaming and moistening seem to have affected the di- gestibility of the protein especially. It is possible that the large decrease observed may have been caused by an ex- traction of soluble nitrogenous matters, though care seems ♦ Landw. Versuclis-Stationen, VII., 243, 324, 387, and 467. \ Homberger : Landw. Jahrbiicher, VIII., 933. MANUAL OF CATTLE-FEEDING. 267 to have been taken to avoid tliis, but no irict'ease of digest- ibility as a result of cooking is shown. In these experiments the steamed fodder was purposely allowed to cool before it was used, in order to observe only the effect of cooking, and no preference for the steamed fodder on the part of the cattle was observed, but rather the reverse. In practice, however, the palatability of a fodder may often be very considerably increased by suita- ble preparation, and the ammals thus induced to eat larger quantities of a fodder not perhaps agreeable to them in its natural state. It would seem that some gain must also accrue from warm fodder (see p. 239). The preparation of fodder may thus produce very favorable results in a prac- tical point of view, although the quantity of nutrients which an animal extracts from a given amount of dry substance is no greater in one case than the other. As in the case of coarse fodder, the digestibility of con- centrated fodders is not increased by the method of prep- aration. This is shown, e. ^., by experiments made in Mockern on feeding bran to oxen ; not only was the diges- tibility not increased, but, on the contrary, decreased more or less by boiling, addition of leaven and production of in- cipient fermentation, and stiU more by successive treatment with alkalies and acids. The effect was greatest on the protein and least on the non-nrtrogenous constituents. Digestibility by Different Kinds of Animals. — The different kinds of ruminating animals, as oxen, cows, sheep, and goats, digest the same fodder equally well. As a mean of about forty single determinations, the di- gestibility of all the constituents of meadow hay is found to be about 2 per cent, greater in the case of oxen and cows than in that of sheep, while, in a still greater num- ber of experiments, clover-hay or green clover is found 268 MANUAL OF CATTLE-FEEDING. to be digested 2 to 3 per cent, better by sheep than by oxen and cows. Tlie differences, small in themselves, thus fully compensate each other in the two kinds of hay. In feeding-experiments on goats, likewise, average diges- tion coefficients have been observed in all experiments yet made. In the case of a non-ruminating animal, like the horse, coarse fodder is less completely digested than by rumi- nants. A large number of experiments on the comparative di- gestibility of various feeding-stuffs by the horse and sheep liave lately been executed at the Hohenheim Experiment Station, under "Wolff's direction. A comparison of all the results yet obtained ^ leads to the following conclusions : 1. Meadow-hay is less fully digested by the horse than by sheep, the difference amounting to 11 to 12 per cent, of the water-free substance. 2. The crude protein of hay is nearly as digestible by the horse as by sheep. In the better qualities of hay ex- perimented upon, the difference amounted to 4 to 6 per cent, of the total amount, while in some of the poorer sorts more was digested by the horse than by sheep. This appears to be the case not only with the total nitrogenous matters but also with the true protein (compare p. 265). 3. Of the non-nitrogenous constituents of hay, the nitro- gen-free extract is slightly, and the crude fibre considera- bly better digested by sheep than by the horse. As a result, the nutritive ratio of the portion of the hay di- gested is narrower in the case of the horse than in that of sheep. As regards fat, all the experiments gavo very low results for this nutrient, owing to the presence of a con- • Landw. Jahrbiicher, VIII. , I. Supplement, p. 97. MANUAL OF CATTLE-FEEDING. 269 Biderable qnantitj of biliarj products, etc., in the excre- ments. 4. Of two kinds of lucerne liay, the protein and nitro- gen-free extract were equally well digested by the horse and by sheep, while the crude fibre appeared to be rela- tively somewhat better digested than that of meadow hay. 5. The digestibility of straw (of winter wheat) was found to depend somewhat on the amount of mastication it received, but in general to be small. Under ordinary cir- cumstances it seems to be hardly half as well digested by the horse as by ruminants. 6. Concentrated feeding-stuffs (oats, beans, and maize, the two latter soaked with water) are digested to the same extent by the horse and by sheep. Similar observa- tions have been made regarding the digestibility of con- centrated fodders by the hog. All these conclusions apply, in the first place, only to the conditions of these experiments, but, at the same time, there is every reason to expect that they will be confirmed by subsequent investigation, at least in their main features. Influence of Breed. — If the various species of rumi- nants digest their fodder to the same extent, we should still less expect to find important differences in this respect between the breeds of one and the same species. In fact, repeated experiments in Dresden and Hohenheim have agreed in showing that, e. g., Merinos, Southdown s, and the so-called Wurtemberg Bastard-sheep, both when store-fed and on an exclusive ration of meadow or clover- hay, as well as on a more or less rich fattening fodder, digest the same feeding-stuffs about equally well. In these considerations we nmst not confuse the digesti- hility of a fodder with its nutritive effect. The latter may be very unequal in the different breeds, and is determined, 270 MANUAL OF CATTLE-FEEDING. on the one hand, h\ the appetite of the animal and the quantity of fodder which it can eat and digest day by day, and on the other, hand, by the whole organization of the animal and its temperament and congenital peculiarities. With this, however, the actual percentage digestibility of a fodder has primarily nothing to do. The latter is essentially the same in all breeds for the same fodder, it beinff, of course, assumed that thei*e are no individual peculiarities of digestion to disturb the result. Age of the Animals. — Even at different ages or in different stages of growth the digestive power for any given fodder seems to be nearly the same, provided that the animals are weaned from milk and that the fodder is agreeable in taste and sufficient in nutritive effect. This fact has been shown by experiments made in Ilohenheim * on lambs of two races, and continued for nine months con- secutively (from the fifth to the fom-teenth month of their age), and which included both exclusive hay fodder and rich feeding with hay and grain. Kecent experiments made by Weiske f on lambs, extending over about ten months, have given the same result. It is of course possible that this constancy of digestive power would be less marked in case of a poor and diffi- cultly-digestible fodder, but young animals, so long as they are capable of and inclined to ]-apid growth, cannot thrive on such a fodder ; they consume a quantity insufficient for their normal nourishment, and must suffer under a long continuance of such treatment. Individual Peculiarities have often a greater influence on the digestive process than the breed or even the species of the animal. ♦ Landw. Jahrbiiclier, II., 219. flbid., IX., 205. MANUAL OF CATTLF.-FEEDING. 271 Besides temporary disturbances of digestion and the weak digestion caused by old age, animals of the same species and breed and of the same age and live-weight often show constant differences in digestive power, which, however, seldom exceed 2 to 4 per cent, of the total dry matter of the fodder. Greater differences in digestive power sometimes show themselves in single individuals which fall strikingly below other animals of the same age in development and live- weight. For example, a difference of 7 per cent, in the digestibility of the total organic matter, and of 15 per cent, in that of the crude fibre, was observed in such a case in Proskau. At the same time, however, it was found that those animals of a herd which attained the greatest live-weight in a certain time on a given kind of fodder did not always possess the greatest digestive power nor produce the most live-weight fi'om the same weight of food. The greater or less appetite, and the quantity of fodder daily eaten, are much more important conditions of the increase in weight of growing or fattening animals than an increased digestive power. Actually stunted animals, those which have been insuffi- ciently nourished in youth, especially during suckling, have also generally a relatively Aveak digestive power in later sta- ges of development. How far the latter can be strengthened by the manner of rearing still remains to be investigated. Effect of Work on Digestion.— A question of some importance is the effect of the performance of work on the digestibility of the fodder. In the recent experiments at Hohenheim on the horse, already alluded to, this question was made the subject of investigation.* ♦ Landw. Jabrbiicher, VIII., I. Supplement, p. 73. 272 MANUAL OF CATTLP>FEEDING. Two series of experiments were made. In the first, tlie daily ration consisted of 13.2 lbs. of oats, 11 lbs. of hay, and 3.3 lbs. of cut straw ; in the second, of 16.5 lbs. of hay and 8.8 lbs. of beans. In the following tables are to be found the amount of work performed per day in each experiment, and the percentage digestibility of the several nutrients, reckoned on the total ration. Series I. Work performed per day. Kilogramme-meters. 475,000 950,000 1,425,000 950,000 475,000 600,000 1,800,000 600,000 Digestibility. Total Organic substance. Per cent. Protein. Per cent. Fat. Per cent. Crude fibre. Per cent. 58.73 70.84 52.05 31.24 58.63 67.63 52.55 29.03 58.60 69.95 45.90 32.33 56.41 66.62 48.73 25.82 54.82 68.21 45.99 26.95 Nitrogen- free extract. Per cent. 68 27 69.61 68.27 67.65 64.41 Series II. 60.04 77.46 24.00 38.55 58.48 75.00 12.61 34.73 57.69 74.60 10.12 34.50 66.80 67.30 66.05 In each series the digestibility decreases slightly toward the close, but this is obviously independent of the amount of work performed. It was probably caused by a deterioration in the quality of the hay consequent on keep- ing and handling. In these experiments, then, the digestibility of the fod- der was not affected by the amount of work performed. MANUAL OF CATTLE-FEEDING. 273 Presumably, this is true in all cases, but these are the only experiments yet made on this point. § 3. Digestibility op Concentrated Fodders and their Influ- ence ON that op Coarse Fodder. Method of Experiment. — The foregoing section shows clearly that the percentage digestibility of coarse fodder, so long as the latter forms the exclusive ration, is de- termined very largely by the chemical composition of its dry matter as affected by the time of cutting, weather, soil, manure, etc., while other circumstances, such as quan- tity, state of dryness, and method of preparation, as w^ell as the kind, breed, and age of the animals, have very little influence upon it. This is an important result, and one of practical worth in the calculation of the daily ration of an animal. It is, however, still more important to investigate whether and how much the digestibility of the constituents of coarse fodder is altered by the addition of concentrated fodders, as well as to determine the digestibility of the latter. In the nature of the case it is practically impossible to make direct experiments w^itli concentrated fodders, since they are not suited for the requirements of herbivorous animals. The best we can do is to feed increasing quan- tities of any concentrated fodder along with a fixed quan- tity of coarse fodder of known digestibility, and ascertain the digestibility of the mixture as a whole. It is, of course, in most cases impossible to determine with certainty what portion of the digested nutrients comes from the coarse fodder and what from the concentrated fodder ; but results may be reached which possess sufficient exactitude for the purpose of compounding rations. 12* 974 MANUAL OF CATTLE-FEEDING. If a concentrated f(xlder decreases the digestibility of the coarse fodder with which it is fed, we should expect that with a greater relative quantity of the former in the ration the decrease in the digestibility of the ration as a whole would be also greater. We therefore proceed as follows : in a fii'st period we determine the digestibility of the coarse fodder — hay, for example — when fed alone. In a second period we add to the hay a certain amount of the concentrated fodder in question — maize meal, for instance — and determine the digestibility of the mixture. In a third period we increase the relative quantity of meal very considerably, and deter- mine the digestibility of this mixture. Now, assuming the digestibility of the hay to have been the same in the second and third periods as in the first, we calculate, from our experimental results, the digestion co- efficients for the maize meal in the second and third periods. It is obvious that, if neither feeding-stuff has altered the digestibility of the other, these two sets of digestion co- efficients ought to be the same within the limits of experi- mental error, and, in that case, we have not only proved this fact but have also determined the digestibility of the maize meal. On the other hand, if the digestibility of either feeding- stuff has been diminished by the presence of the other, it is plain that our method of calculating the results will show an apparent decrease in the digestibility of the maize meal. In the case supposed it would be impossible to determine directly in which of the two feeding-stuffs the decrease took place, and the method of expressing the results would depend partly on the results of other experi- ments and partly on questions of convenience. MANUAL OF CATTLE-FEEDING. 275 Some of the examples contained in the following para- graphs will, perhaps, make the method of calculation clearer, while they at the same time serve to elucidate some of the practical questions that arise. These questions concern chiefly the influence of concen- trated fodders on the digestibility of coarse fodder, and to them we shall devote most of our attention, since it is im- possible, within the limits of this work, to notice the numerous experiments on the digestibility of the various concentrated fodders. For the results of the latter the reader is referred to the Appendix. Effect of Albuminoids. — E. Schulze & Marcker,* in Weende, have made experiments on the effect of a prepara- tion of wheat-gluten containing 78 per cent, of albuminoids on the digestibility of meadow-hay. They experimented on sheep, and obtained the following results for the per- centage digestibility of the hay, on the assumption that the gluten was wholly digested : Protein. Crude Fibre. Fat and nitrogen- free extract. Total organic matter. Hay alone 57 53 -4 57 58 + 1 66 67 + 1 62 Hay and 119.4 grms. gluten.. Difference 63 + 1 A second experiment, with a larger amount of gluten, gave, on the same assumption, the following results : Hay alone Hay and 262.2 grms. gluten. Difference. Protein. 55 49 Crude Fibre. 55 Fat and ni- trogen-free extract. 65 61 Organic matter. 61 60 * Jour, fiir Landwirthschaft, 1871, p. 68. 276 MANUAL OF CATTLE-FEEDING. The slight decrease in the digestibility of the protein of the hay becomes so exceedingly small, when calculated on the whole ration, as to be of no practical significance, while the gluten exerted practically no influence on that of the remaining nutrients. Thus, these results show not only that even these large additions of albuminoids to the fodder produced no essential alteration of digestibility, but also that the gluten was almost completely digestible. Very similar results were obtained in a series of experi- ments, executed at Ilohenheim,"^ on the digestibility of " flesh meal " by swine. It was fed in varying quanti- ties along with potatoes. Assuming that the digestibility of the potatoes was not altered by the addition of the highly nitrogenous flesh meal, the following numbers were obtained for the digestibility of the latter : Number of animal. Fed. Digestibility of Flesh-Mbal. Period, Potatoes. Grms. Flesh meal. Grms. Protein . Per cent. Fat. Per cent. Organic substance. Per cent. III Ill 2 3 1 4 2 3 1 4 4,500 5,000 5,000 4,500 6,500 8,000 7,500 7,500 6,063 190 210 500 450 195 240 235 225 279 95.1 97.0 98.5 98.9 102.9 96.4 91.4 98.6 97.4 82.3 87.5 88.7 88.5 75.2 90.7 83.3 89.6 85.7 93.4 96.1 93.5 90.9 94.3 86.9 87.8 90.4 Average 91.7 * Landw. Jahrbiicher, VIII., I. Supplement, p. 200. MANCTAL OF CATTLE-FEEDING, 277 Though the ratio between potatoes and flesh meal varied between wide Hniits, the digestibility of the latter, calcu- lated on the basis of unaltered digestibility of the former, varied but very little, and rather increased than decreased in the experiments in which relatively most flesh meal was fed. Since the flesh meal contained no crude fibre or ni- trogen-free extract, the digestibility of these ingredients of the potatoes could be deterinijied directly in each ex- periment. It was found to bo- sensibly the same in all. Obviously, the results of these experiments are as if the potatoes were equally well digested in all cases, and as if the above coefficients representtid the digestibility of the flesh meal ; and though this f a^it cannot, perhaps, be said to be absolutely proved, the practical result is the same as if it were, and we can make it the basis of calculations of digestibility in similar cases. Nitrogenous Bye-Fodders. --By means of experiments made on the same plan as those just described, it has been found that for the ordinary nitrogenous bye-fodders, such as oil cake, cotton-seed cake, bran, beans, etc., digestion coefficients may be obtained, and that these coefficients remain nearly constant whatever the quantity of the fodder given, while the digestibility of the coarse fodder remains unaltered by the addition of the concentrated fodder. This conclusion is drawn from the results of numerous digestion experiments in which increasing quantities of the concentrated fodder were fed along with meadow or clover hay. Such experiments have been made in Tlohenheim, Mockern, and Halle, especially with oil cake, but also with crushed beans, rape cake, wheat bran, and cotton-seed meal, on sheep, goats, and oxen, with the results stated. In all probability, experiment would show that the same 278 MANUAL OF CATTLE-FEEDING. thing is true of other highly nitrogenous bye-fodders, e. g.^ all kinds of oil cake, the legumes, brewers' grains, etc. The results of these determinations of the digestibility of bye-fodders are included in Table II. of the Appendix. As the general result of the experiments, we can say that nitrogenous hye-fodders do not decrease the digestibility of the coarse fodder with lohlch they are used. The Grains. — The influence of the grains, i. e., of con- centrated fodders with a medium nutritive ratio (1 : 5-S), on the digestibility of coarse fodders has received compar- atively little attention. Oats have been the subject of experiments by Hof- raeister & Haubner ^ and by Wolff f on sheep. In both investigations it was found that an addition of oats to the coarse fodder did not essentially alter its digestibility. Wolff obtained the following results, on the assumption that the digestibility of the coarse fodder (hay) was not altered : Ratio of hay to oats. Crude protein of oats digested. Per cent. 1 : 1.76 78.0 1 : 3.09 78.4 1 : 3.30 78.5 The constancy of the digestion coefficient for oats shows, as explained above, that the assumption of unaltered diges- tibility of the coarse fodder is probably correct, and can at least serve as a basis for the calculation of rations. Hof- meister & Ilaubner's results were, on the same assumption, as follows : Eatio of hay to oats. 1 : 0.18 Crude protein of oata digested. Per cent. 74.0 1 : 0.44 74.1 1 : 0.75 67.3 * Landw. Versuchs-Stationen, VI., 185 and 301. f Landw. Jahrbiicher, 11., 288. MANUAL OF CATTLE-FEEDING. 279 Here we have also a nearly constant coefficient for the protein of the oats, except in the last case, where a slight depression is observed, which may indicate an actual de- crease in the digestibility of the hay. The oats used in Wolff's experiments had a considerably narrower nutritive ratio (1 : 5.16) than those used by Hofmeister & Haubner, (1 : T.07), and it is quite possible that the slightly smaller digestibility in the latter case, as well as its decrease in the third experiment, is due to this cause. The digestion coefficients of the other constituents of the oats, except those of crude fibre, whose digestibility generally shows considerable variations in all the grains, were nearly accordant in all the experiments. The recent comparative experiments on the horse and sheep, made at Ilohenheim, and to which reference has ,more than once been made, included determinations of the digestibility of oats, maize, and beans, when fed with coarse fodder. In no case was any noticeable influence of these feeding-stuffs on the digestibility of the coarse fod- der observed. Experiments in Weende by E. Schulze & Marcker * seem to indicate that when the nutritive ratio of the grain or of the whole ration is wide (1 : 8-10), the digestibility of the coarse fodder may be diminished. We shall pres- ently see that feeding-stuffs rich in carbhydrates, especially roots, decrease the digestibility of coarse fodder. Grain with a nutritive ratio of 1 : 10, like that used in Weende, begins to approach roots in composition, and may produce a similar effect ; but we may safely say that grain of good quality (nutritive ratio 1:5-6) produces no decrease in the digestibility of coarse fodder. * Jour. f. Landwirthschaft, 1875, 163. 280 MANUAL OF CATTLE-FEEDING. Effect of Carbhydrates. — All investigation goes to show that increasing the protein of a ration has no ten- dency to diminish the digestibility of the latter, but rather to increase it. The carbhydrates, on the contrary, when added in large quantities to a ration, depress the digestibility of the crude fibre, and especially of the protein, to a considerable ex- tent. This has been observed in numerous experiments on oxen, cows, sheep, and goats, both when pure carbhydrates were fed and when fodders containing large amounts of these substances were used. Starch. — In the earlier Weende experiments this effect of starch on the digestibility of coarse fodder was observed, and the observation has been fully confirmed in later in- vestigations. Experiments of this sort have the advantage over many digestion experiments that it is possible to ascertain whether or not the starch is entirely digested. This sub- stance is free fi'om protein, and hence any decrease in the dit'-estibility of the latter must fall exclusively on the rest of the fodder. The same is true of the crude fibre and fat, while as regards the nitrogen-free extract, it is easy to determine, by a microscopic examination of the excrements, whether any of the starch has escaped digestion. The re- sults, therefore, possess no ambiguity. The following table contains a summary of the results of experiments by Henneberg & Stohmann, E. Schulze & Marcker, Stohmann, and Wolff, compiled from Wolff.* The first column contains the name of the experimenter ; the second, the amount of starch fed, expressed in per cent, of the dry matter of the remaining fodder ; the third Bmahrung Landw. Nutzthiere," pp. 139-145. MANUAL OF CATTLE-FEEDING. 281 shows the character of the other fodder ; the fourth and fifth express the decrease in the digestibility of the protein and crude fibre in per cent, of the quantity of each which was digested when the starch was withheld. Deckeasb in Di- No Authority. Starch in per cent, of other fodder. Fodder, exclusive of starch. gestibility OF Protein. Per cent. Crude fibre. Per cent. 1.... 2.... 3... Henneberg & Stohmann. 15 18 29 r Clover-hay, | y straw, and -j 1 beans. 7 11 21 6 7 15 4.... 5.... " " " 9 9 I Same with j ^ more beans, j 3 4 4 2 6.... Schulze & Miircker. 25 Hay. 41 10 7.... u » .. 25 Hay and beans. 20 13 8.... stohmann. 15 Hay. 12 12 9.... " 69 44 7 10.... " 15 Hay and oil-cake. 9 10 n.... Wolff (experiments on hogs). 15 Barley. 12.... " " " 31 " 11 Two things are shown by this table : first, the greater the amount of starch which is added to a ration, the more is the digestibility of the protein and crude fibre decreased, e. g., in experiments 1, 2 and 3, or 8 and 9 ; second, the richer the original ration is in protein, the less is the de- pression caused by a given quantity of starch, e. ^., Experi- ments 6 and 7. But this amounts to saying that the protein and crude fibre of a ration are better digested the narrower the nutritive ratio of the latter, a fact which, it will be remem- bered, we have already noticed in the case of hay, and 282 MANUAL OF CATTLE-FEEDING. which Stohmann has made the basis of his formula (p. 256) for calculating the digestibility of the protein of a ration from its chemical composition. A large number of results seem to indicate strongly that this is a general law, of which the experiments cited above are only special cases, and that the non-nitrogenous matters of hay, e. g., as truly depress the digestibility of its protein and fibre as does the addition of starch. The only difference is that we can- not abstract the non-nitrogenous matters from the hay and observe the digestibility of the other constituents, but must determine the digestibility of the hay as a whole. The statement that starch decreases the digestibihty of other fodder, then, is simply a practically convenient way of stating the result in this particular case. Sugar. — ]^ot many expermients on the influence of sugar on the digestibility of rations have been made ; but those which have been executed show, as was to be ex- pected, that widening the nutritive ratio of a ration by means of sugar produces essentially the same result as when effected by starch. The decrease in the digestibility appears to be rather smaller, however. Effect on Digestibility of Nitrogen-free Extract. — Thus far we have considered chiefly the effect of easily digestible carbhydrates on the digestibility of pro- tein and fibre. In regard to the nitrogen-free extract and the fat of the coarse fodder, it may be said that the diges- tibility of these constituents is not essentially decreased by starch or sugar so long as the latter are completely di- gested. Frequently, however, the starch or sugar not only dimi- nishes the digestibility of the protein and fibre, but escapes digestion itself to a not inconsiderable extent, thus causing a double loss. We have here another indication of the MANUAL OF CATTLE-FEEDING. 283 necessity of observing a medium nutritive ratio in the fodder of farm animals. Indeed, a too-wide nutritive ratio may cause more waste than a too-narrow one. In the former case the protein consumption is, as we learned in Part I., needlessly in- creased, but the nitrogen of this protein is excreted in the urine, and has its value in the manure. In the second case, a too-wide nutritive ratio also causes a waste of pro- tein by decreasing its digestibility, but it also causes some of the starch to pass through the body without being put to any use, while as manure the latter is absolutely value- less, containing only elements of which the atmosphere offers an inexhaustible supply to plants. Roots. — It will not often be the case in practice that pure starch or sugar is fed, but potatoes and roots, which are especially rich in carbhydrates or pectin substances, must exert a sunilar influence on the digestibility of coarse fodder. It is to be expected, however, that the resulting depression will be smaller than that caused by pure carbhydrates, since the above-named fodders contain, be- sides starch and sugar (or pectin), other substances, and especially more or less albuminoids. The effect of roots aixl potatoes on the digestibility of a ration has been investigated chiefly at the Hohenheim Ex- periment Station, where a large number of experiments on sheep have been executed.* In calculating the results of these experiments the pota- toes and roots have been considered as wholly digestible, and any decrease in the digestibility of the ration is con- sidered as affecting exclusively the remaining fodder. The * Landw. Jahrbiicher, VIII., I. Supplement, p, 123. Compare also Wolff's "Ernahrung Landw. Nutzthiere," pp. 158-175. 284 MANUAL OF CATTLE-FEEDING. grounds which justify this assumption are two : first, it is known that these feeding-stuffs are very completely if not wholly digested, and that large amounts of starch or sugar do decrease the digestibility of a ration ; second, with our present knowledge this method of expressing the results is the most convenient for practical purposes. It should never be forgotten that investigations of this sort are of a practical and not a physiological nature. In feeding, it is not the digestibility of one feeding-stuff so much as that of the whole ration which is of importance, and hence that method of expressing the results of digestion experiments is best which attains this end by the simplest method con- sistent wdth accuracy. Probably roots are not wholly digestible, but at present it is not possible to calculate di- gestion coefficients for them as has been done for the other bye-fodders. Calculated on this basis, these experiments yielded, in general, the same results as those on the feeding of starch and sugar, viz. : that the depression of the digestibility was greater, the larger the amount of the bye-fodder and the wider the nutritive ratio. The following table by Wolff, in which the results are grouped according to the propor- Depbession .— Peb cent. Dry matter of bye- fodaer in per cent, of coarse fodder. Protein. NitroRen-free extract. Organic substance. Potatoes. Roots. Potatoes, Roots. Potatoes. Roots. 12 to 18 7.3 4.0 5.3 2.2 4.4 3.0 22 to 35 13.9 7.1 6.5 4.7 7.5 5.9 44 to 54 27.8 11.9 14.7 6.8 17.1 9.3 64 to 95 40.2 22.3 13.9 10.2 17.5 11.7 MANUAL OF OAT^Jl^^KHTOSf fe^^^^ * 285 tion of bye-fodder, will serve to give an idea of the extent of the depression. The numbers denote the decrease in the digestibility of the protein, nitrogen-free extract, and total organic matter, under the influence respectively of roots and potatoes. The depression is calculated in per- centages of the amounts of the several nutrients digested when the bye-fodder was withheld. The decrease in the digestibility of the non-nitrogenous ingredients caused by any amount of roots or potatoes likely to be fed in practice is so small that we may neglect it, and consider only the effect on the protein. From the above numbers, Wolff concludes that we can assume that, when the dry matter of the bye-fodder of ruminants amounts to ^, i, i, and finally equals that of the coarse fodder, the digestibility of the crude protein of the latter is decreased by about 7, 14, 28, and 40 per cent, if the bye-fodder consists of potatoes, and by about half as much if it consists of roots. It is plain, however, that these numbers can be but ap- proximations, since, in general, the decrease of the digesti- bility varies with the nutritive ratio of the whole ration. It seems probable that, in practice, the most satisfactory method would be to use these figures as a basis for com- pounding a ration, and then to compute the digestibility of the total crude protein by means of Stohmann's for- mula (p. 256). In cases of doubt, it is well to err in giv- ing slightly too much rather than too little protein, not only for the sake of ensuring the digestion of the non-nitroge- nous nutrients but to ensure also a sufficient supply of the important albuminoids to the animal. For siijjiilar reasons it is w^ell, when feeding large quan- tities of roots along with hay or straw, to add to the ra- tion a small amount of some highly nitrogenous bye-fod- 286 MANUAL OF CATTLE-FEEDING. der, like oil cake, in order to narrow tlie nutritive ratio and ensure as complete a digestion as possible, both of the nitrogenous and the non-nitrogenous nutrients. As noted, all the above experiments were made on sheep, and their results are applicable, in the first place, to rumi- nants. A similar depression in the digestibility of the crude protein in the food of the hog is produced bj starch, and presumably by roots, while the digestibility of the non- nitrogenous nutrients seems little or not at all affected. Finally, it should be added that the digestibility of pota- toes, wdien fed exclusively to hogs, has been the subject of investigation at the Experiment Stations of Proskau and riohenheim. The results of these experiments are inclu- ded in Table II. of the Appendix. Effect of Fat. — Experiments on the effect of the ad- dition of small amounts of fat or oil to a ration on the digestibility of the constituents of coarse fodder have hitherto given very variable and more or less discordant results. There is little doubt that in high feeding, intended to cause a rapid production, the fat of the ration is of im- portance, and has considerable influence on the nutritive effect, but the weight of evidence goes to show that the digestibility of the various nutrients is not essentially al- tered by an addition of fat to the fodder. Care must be taken, however, not to give ruminating animals too much fat, since it may easily cause a gradual loss of appetite and even serious disturbances of diges- tion. It is to be noted that such an injurious eifect is much less noticeable when the fat forms an actual con- stituent of the fodder, as, e. g.^ in oil cake, etc., than when pure fat is mixed with the fodder. This is illustrated by some Ilohenheim experiments on MANUAL OF CATTLE- FEEDING. 287 sheep. The fodder was tolerably i-ich in protein, and by the gradual addition of increasing quantities of palm-nut meal and flaxseed the amount of fat per day and head was increased finally to 75 and 100 grammes, wliile tlie quantity of the remaining nutrients was scarcely altered. The di- gestibility of the fodder was not affected at all, either favorably or unfavorably, and the health of the animal did not suffer. Effect of Salt. — That salt plays an important part in the nourishment of the animal organism, and is for the herbivora, even more than for the carnivora, an indis- pensable food, has been already explained. Upon the digestibility of the fodder, however, it seems to exert no considerable influence in any way. The result of direct experiments in Salzmiinde, Hohenheim, Dresden, and Proskau, has been to show sometimes an apparent de- crease, and sometimes an apparent increase, of digestibility as a result of the feeding of salt. Generally, however, under wholly normal conditions, salt has shown itself without influence in this respect. The greater palatability of a fodder, and the larger amount consequently eaten as a result of salting, is not to be confounded with its percentage digestibility, which, as we have seen (p. 259), is in general little affected by the quantity eaten, especially of coaj'se fodder. Besides salt, other inorganic matters are sometimes fed, especially phosphate of lime. This is not the place to con- sider the necessity of such a procedure, nor its effects on the nutrition of the animal. Here it need only be said that, like salt, they appear to exert no effect on the digest- ibility of the organic nutrients. CHAPTER n. THE COARSE FODDERS. In the preceding chapter, we have considered, in a gen- eral way, the digestibility, and incidentally some of the other properties, of the more common classes of feeding- stuffs. We now proceed, in this and the following chap- ters, to take np the chief members of these classes for a more detailed study. In this we shall regard the feeding- stuffs chiefly as sources of the various imtrients — that is, we shall look at them from a chemical standpomt, and make their composition the prominent point. The greater or less adaptability of particular fodders to particular kinds of animals we shall leave entirely out of account, simply because it is as yet entirely a matter of practical observation and experience. The subject of the cultivation of fodder plants, too, is outside the scope of tliis work, and will only be alluded to incidentally, in so far as the different methods of cultivation and manuring may influence the composition or digestibil- ity of the resulting crop. § 1. Meadow Hay, Rowew, and Pasture Grass. Variable Composition. — While the seeds of the same plant, and hence their bye-products, are generally quite constant in their chemical composition and nutritive value, it is characteristic of the stems and leaves, which constitute what we call coarse fodder or forage, that they vary very MANUAL OF CATTLE-FEEDING. 289 considerably in composition, according to the circumstances under wliich they grow, their state of maturity, etc. It is, therefore, of the highest importance to learn how these various factors affect the value of a fodder. In the follow- ing paragraphs we shall consider their influence on the composition of hay, premising that it is essentially the same on all coarse fodders. Supply of Plant Food. — It is a well-established fact that the natural quality and the fertility of a soil have a very considerable influence on the chemical composition of the crop, especially of coarse fodder. This influence is particularly noticeable on the nitrogen- ous constituents of the fodder. According to analyses made in Tharand, the hay from a manured meadow contained 12 per cent, of protein, that from an unmanured one only 9 per cent. Still greater differences often show themselves when dark green, " rank " plants are compared with pale yellowish-green ones of the same kind, occurring in the same field, and of the same age. This was observed, e. g., in investigations made in Mockern. Eank plants of oats, barley, wheat, and rye contained at the beginning of flowering 16.4 per cent, of protein in the dry matter, while weaker plants contained only 10.4 per cent. It is not improbable that the low percentage of crude protein which seems to be characteristic of American, or at least of New England, hay, as compared with that raised in Germany and Austria (compare '' Eeport Conn. Ag'l Expt. Station," 1879, pp. 79-83), is owing to its having been raised on poorer soils. Some analyses made by Weiske & Wildt,* in Proskau^ * Jahresber. Agr. Chera., XITI., III., 9. 13 290 MANUAL OF CATTLE-FEEDING. are of interest in this connection. The fodder grew on a heavy clay soil, and consisted, for the most part, of timothy {P Mew n J) rate use), with a slight admixture of red clover. One sample (I.) came from a part of the field which was in an ordinary state of fertility ; the other (11.) was taken from spots where the excrement and urine of the grazing animals had caused an especially luxuriant growth. The two samples had the following composition in the water free state: Protein. Per cent. Crude fibre. Per cent. Fat. Per cent. Nitrogen- free extract. Per cent. Ash. Per cent. L 11.0 20.3 22.5 26.6 4.2 4.8 56.3 41.3 6.0 II 7.0 The differences are very considerable, especially in the amount of protein and nitrogen-free extract. It is noticeable that the greatly increased percentage of protein in II. is accompanied by a not inconsiderable in- crease in the quantity of crude fibre, in consequence of which the digestibility of the protein is most probably diminished. According to practical experience, a very rank fodder, such as grows on heavily-manured land, and especially in wet and shady places or in wet seasons, is not especially nutritious, even though it contains much crude protein. This may be partly because the protein is less digestible and partly because the bulk and coarseness of the fodder render it unpalatable. Moreover, high ma- nuring, especially with nitrogenous fertilizers, tends to in- crease the proportion of "non-protein," which is less valuable, in some respects at least, than true protein. It would be very interesting to make systematic diges- MANUAL OF CATTLE- FEEDING. 291 tion experiments with the different qualities of fodder obtainable by different manuring of the same soil, in order to determine the actual practical value of high manuring for fodder crops. As yet this has not been done. Method of Curing. — The method of curing almost universally adopted in this country is drying. Evidently^ this alone cannot change the composition of the dry mat- ter of the fodder, and we have seen that the digestibility is in no essential degree affected when the drying is care- fully conducted. On the other hand, it has been already stated that in the preparation and handling of hay, as commonly con- ducted, more or less loss of substance is unavoidable, and that this loss consists of the most nutritious parts of the plants. As a result, both the composition and digestibility of the hay suffer (compare p. 306). Obviously, it is desirable to reduce this loss to the mini- mum. Hence all methods and appliances which diminish the amount of handling which the hay must receive, espe- cially when it is nearly dry, tend to improve the quality of the product. So, too, it is desirable to dry the grass as little as is consistent w^itli the object of curing, viz., to ensure the keeping of the fodder, since the dryer and more brittle it becomes, the greater is the loss by handling. In the process of " ensilage," long practiced in Europe and lately introduced into this countrj^, these losses are largely avoided, the fodder being placed in the silo while still green. On the other hand, the process of fermenta- tion w^hich the fodder undergoes causes losses in other ways. In this country ensilage has been chiefly recom- mended for maize, and we shall consider it more fully in that connection. Damage by Rain. — In our hot and dry summers, in 292 MANUAL OF CATTLE-FEEDING. which haj can usually be sufficiently cured in a single day, hay is far less exposed to damage from rain than is the case in the moist climate of Germany and England. At the same time it is impossible to altogether avoid it, and it is therefore of interest to know its effects on the hay. Both analysis and digestion experiments confirm the common observation that hay which has been wet is dim- mished in value. A loss of crude protein and nitrogen-free extract, and a relative increase in the crude fibre, are gen- erally observed, combined with a decreased digestibility. Stage of Growth. — As has been already pointed out (p. 33), plants while still young and rapidly growing con- tain relatively more protein and less fibre than more ma- ture ones. Consequently, early-cut fodder must, other things being equal, be of better quality than late-cut. This is well illustrated by the following analyses, executed at Hohenheim,* of hay cut at three different times from the same meadow : Water-free Substance. Cut. Protein. Per cent. Crude fibre. Per cent. Fat. Per cent. Nitrogen- free extract. Per cent. Ash. Per cent. May 14, 1877 June 9, " "26, " 18.97 11.16 8.46 24.70 34.88 38.15 3.42 2.74 2.71 43.91 43.27 43.34 9.50 7.95 7.34 The table shows a decrease of crude protein and an in- crease of crude fibre, both of which impair the quality of the fodder. Furthermore, we have seen (p. 263) that early-cut fodder, * Landw. Jahrbuclier, VIII. , I. Supplement, 54. MANUAL OF CATTLE-FEEDING. 29; like that of May 14tli, is much more digestible than that cut later, and the real value of a fodder is, of course, measured by the amount of digestible nutrients it contains. In the above case 100 pounds of each fodder contained the following amounts of digestible matters : Cut. Digestible organic substance. Pounds. Digestible protein, rounds. Digestible crude fibre. Pounds. Digestible fat. Pounds. Digestible nitrogen- free extract. Pounds. May 14th June 9th " 26th 69.20 59.31 53.45 13.85 8.04 4.74 19.76 23.03 23.27 2.22 1.42 1.17 83 37 26.83 24.27 It will be seen that the total quantity of digestible mat- ters and the amount of digestible protein, the most valu- able of the nutrients, furnished by 100 pounds of the early-cut hay is considerably greater than that yielded by the same weight of that cut later. Many more examples of the same fact might be adduced were it needful. Early or Late Cutting. — The question of early or late cutting is one that is frequently raised, and the considera- tions just adduced enable us to indicate, to some extent, its answer. Three elements enter into the problem, viz., the quality of the fodder, its quantity, and the amount of labor expended upon it. As just illustrated, young plants are relatively richer in protein and poorer in crude fibre than old ones, and there- fore more nutritious ; so that if the only question were the quality of the fodder, the best results would be obtained by cutting as early as practicable. But we have to consider not only the quality of the fod- der but the quantity of it which we can obtain from a given area, and this complicates the question somewhat. 394 MANUAL OF CATTLE-FEEDING. In the young plant protein is formed rapidly, but as it. grows older the vital activities are directed more to the translocation of protein already present than to the pro- duction of new. This is especially the case after blossom- ing, when the protein before present in the stems and leaves is transferred to the seeds and there stored away. At the same time a continual formation of woody fibre goes on, so that a large proportion of the increase in weight of plants after a certain point is due to this substance, and al- though the absolute quantity of protein is not decreased, its percentage in the whole mass of the plant is. When crops are raised for fodder, the object generally is to produce the greatest possible amount of digest Ihle nutrients per acre. If it were a question simply of producing the greatest num- ber of pounds of nutrients, digestible or indigestible, per acre, if we w^ere confined to one crop in a season, we should let that stand as long as possible, since we have no evidence that there is any loss of organic matter during ripening. But supposing, for the present, that only one crop is raised in a season, we have seen that the older plants become, the less digestible they are. For this reason, though we might get a greater quantity of nutrients per acre by letting a year's crop, e. siderable losses incident to field curing. As compared with clover of the same quality, we may assume, with comparative certainty, that the crude protein of lucerne is at least equally digestible. Ou the other MANUAL OF CATTLE-FEEDING. 309 hand, the crude fibre of hicerne is decidedly less digestible than that of clover, the nitrogen-free extract of the two fodders is about equally digestible, and the fat of lucerne, like that of meadow hay, seems to be difficult of digestion. The large proportion of digestible protein which it con- tains renders lucerne both absolutely and relatively a very nitrogenous feeding-stuff. If fed exclusively, especially as green fodder, it supplies an excess of protein, and hence causes a waste of this valuable nutrient. It should there- fore, in most cases, be used in connection with some feed- ing-stuff poor in protein, such as roots or straw, to realize the best effect. Yetches. — The coefficients given in the Appendix for vetches, are the results of six digestion experiments made in Hohenheim on sheep. The fodder was of excellent quality, cut at the very beginning of flowering, and cured in favorable weather; it is therefore not surprising that the digestion coefficients were nearly the same as those of the best clover hay, and for protein even higher. Like lucerne, the vetch is inclined to a rapid formation of woody fibre after flowering, and deteriorates in quality. In Waldau the following percentages of protein and crude fibre were found in the water-fi-ee substance : •-. Protein. Per cent. Crude fibre. Per cent. Cut May 23d " July 12th .o 25.4 13.8 20.8 39 8 In the state in which vetches are generally used for fod- der, however, they may safely be considered to have a higher percentage of protein than clover. 310 MANUAL OF CATTLE-FEEDING. Lttpines. — The yellow lupine yields, wlien cut just at the end of flowering, tlie most highly nitrogenous of all coarse fodders. Experiments by Ileidepriem "^ on lupine hay cut just as the pods were beginning to form, perhaps somewhat ear- lier than is customary in practice, showed that it contained the enormous quantity of 27.8 per cent, of protein in the dry matter. The digestibility of the protein by sheep was foimd to be 74, that is, almost the same as in vetches and lucerne. This seems to indicate that at about 80 per cent, we have reached the maximum to which the digestibility of the protein of coarse fodder can rise, since with about the same percentage of crude fibre the quantity of protein varies in the three fodders just named from about 19.2 per cent, to 27.8 per cent., without producing any consid- erable increase of its digestibility. A striking fact is the high digestion coefficient found for crude fibre (74), while in vetches and lucerne, both of similar composition, it was much lower, viz., about 54 and 38 respectively. If this observation be trustworthy, lupine hay forms an exception to the general rule that the nitrogen-free extract is a measure of the total digestible non-nitrogenous matter ; the relation in this case was found to be 100 : 124, {. bination with other feeding-stuffs less rich in protein. Poisonous Effects. — At various times poisonous effects have been observed to result from the feeding of lupine hay to sheep. These effects have frequently been ascribed to the alkaloids which it contains. In some years and in some places they have been very disastrous, while at other times or in other places no such results have been observed. More recent investigations indicate that the amount of al- kaloids present in the hay is too small to produce any evil results, and that the cause of the poisonous effects is to be sought in fungi which attack the plants under certain, as yet unknown, conditions. Other Legumes. — Besides the plants above described, there are a number of others which serve, to a greater or less extent, as fodder, either alone or in combination with other feeding-stuffs. Numerous analyses of these plants have been made, but only exceptionally have they been the subject of exact di- gestion experiments, and hence their digestibility and value as fodder can be only approximately estimated by com- parison with similar feeding-stuffs of analogous composi- tion. The so-called Swedish clover {Trifolkcm hyhridum) is similar in quality to red clover, except that it is generally more tender and richer in nitrogen and can be fed to ad- vantage in a more advanced stage of development. This is true in a still higher degree of white clover ( T. rejpens\ 312 MANUAL OF CATTLE-FEEDING. which, however, is generally cultivated only for pasturage in conjunction Avitli other clovers and grasses. The Medick {Medicago lupulhid)^ frequently but incor- rectly called yellow clover, must also be considered an ex- cellent fodder, so far as mechanical state and chemical composition go, while the incarnate clover {Trifolmm in- carnatmiib) easily becomes woody, and has less nutritive value. Another forage plant which is stated by some authors" to have been lately brought before the public in Germany under various high-sounding names, is the sweet clover {Melilotus alha), also called " Bokhara clover" and " Stone clover." It does not appear, however, to be of any great importance, except possibly in dry, stony soils. It appears imposing on account of its height, but the proportion of leaves to stem is small, and the coarse stems rapidly be- come very woody, necessitating an early harvest. The ethereal oil (cumarin) peculiar to the plant, too, though agreeable to cattle in very small quantities, renders the fodder unpalatable, if present in more than a trace. On this account, sweet clover should never be fed ex- clusively. When it forms a third, or perhaps, in case of sheep, a half of the whole ration of coarse fodder, the ani- mals eat it freely, and it may be reckoned a fair fodder for sheep, horses, and oxen. It would probably not be suit- able for milk cows, as the cumarin would be likely to im- part a flavor to the milk. Many authorities place a high value on the kidney- vetch {A7ithi/llisvul7ieraria\esi^ecm\\y for light, sandy soils, where clover does not flourish. It is somewhat poorer in protein than the foregoing plants, but also contains less crude fibre, and is not inclined to become woody so rapidly. Among its advantages are reckoned the facts that it is MANUAL OF CATTLE-FEEDING. 313 suited for a liglit, dry soil ; yields a comparatively large quantity of nutrients even in dry years, when most crops are " burned up ; " that the fodder made from it is very wholesome ; that it resists frosts well ; and that in the fall it may be pastured without injury to the next year's crop. It is eaten willingly by sheep and cattle, either green or as hay, and horses soon become accustomed to it. The esparsette or sainfoin {OnohrycJiis sativa) seems, according to our present knowledge, to at least equal red clover in its percentage of protein, and to retain its pala- tability and digestibility to a somewhat later stage of growth. Another plant cultivated on sandy soils — the seradella {OniiUtopus sativics) — yields an especially fine, palatable, and easily-digestible fodder, which has the advantage over other forage plants that it retains its full value to the end of the flowering period. It gives comparatively small crops, however, and in cur- ing, the leaves, i. °8 \t Calf Total nutritive matter. Lbs. 8.85 13.15 18.50 18,50 8.73 15.70 19.30 Digestible protein. Lbs. 0.7 1.5 3.0 3.5 3.0 5.1 4.9 Nutritive ratio. 12 8.0 5.5 4.5 4.5 5.0 4.0 Both the total quantity of nutritive matter consumed by the calf and the amount of protein will be seen to be relatively greater than in the case of any of the other herbi- vorous animals, while the nutritive ratio is narrower. The food of the young calf approaches more nearly in its composition that of well-fed carnivorous animals, as represented by ration h for the dog ; and the resemblance becomes still more close when we consider the compara- tively large ampimt of fat in the food of the calf. The greater relative consumption of food by young ani- mals, as compared with mature ones, is also strikingly shown in the experiments on lambs described in § 3 of this chapter. * The rations for oxen and sheep are Wolff's feeding-standards. Of the two rations for the dog, a consists of 500 grms. fresh meat and 200 grms. fat — quantities which Voit found sufficient to keep an animal weighing about 70 lbs. in fair condition — and h is a richer ration, con- sisting of 800 grms. fresh meat and 350 grms. fat. MANUAL OF CATTLE-FEEDING. 439 Production of Flesh. — We have already learned that the proportion of the albuminoids of the food which is converted into flesh is quite small in full-grown animals, while by far the larger proportion of the protein is de- composed in the body and excreted in the urine. In the young calf, on the contrary, more protein is retained in tlie body than is oxidized and excreted, the result being a rapid gain of flesh. The following table shows the rela- tion between consumption and gain of protein per day for an average animal weighing 100 lbs. : Eaten Pounds. Excreted in dung " Digested " Excreted in urine J ( % I Pounds. Retained in body ■{ i % Nitrogen. Equivalent to protein. .078 .488 .004 .025 .074 .463 .020 .125 27 27 .054 .338 73 73 Notwithstanding the large amount of protein eaten and the narrow nutritive ratio, both of which circumstances tend to increase the protein consumption in the body, the young calf excretes a comparatively small quantity of nitrogen in the urine. While it eats nearly as much protein as a well-fed dog of equal weight, it excretes about as much as the latter animal does in hunger. In other words, the sucking animal (in case of the calf at least) is able to apply a far larger proportion of the al- buminoids which it receives in its food to the building up 440 MANUAL OF CATTLE-FEEDING. of its body than is the case with mature animals. Com- bining this Avith the relatively larger amount of food eaten, we can readily understand the rapid increase in weight of young animals. Production of Fat. — By means of a respiration appa- ratus, the excretion of carbonic acid in these experiments was determined. The following table gives the result per day for the average animal of 100 lbs. weight, and also a comparison with the amount excreted per 100 lbs. body- weight by other animals : Calf 1.95 lbs. Man 1.3—1.4 '• Dog (in hunger) 1.1 " " (well fed) 1.8 " Ox (maintenance fodder) 1.0 " Ox (fattening) 1.3 " Sheep (maintenance fodder) 1,7 " The excretion of carbonic acid is, in general, relatively greater in the calf than in mature lierbivora, and ap- proaches that of the well-fed carnivora. The gain of carbon and consequently of fat per day was also considerable. Carbon per 100 lbs. live-weight. In food 0.98 lbs. Excreted 0.53 " Gain 0.45 " Contained in the protein gained 0.18 *' Gained as fat 0.27 " Corresponding to fat 0.35 '' Fat in the food 0.47 " The amount of fat in the food was sufficient to supply all that was gained. MANUAL OF CATTLE-FEEDING. 441 Inorganic Nutrients. — In one experiment the con- sumption and excretion of the mineral ingredients were determined. The results on an animal weighing 151.2 lbs. were the following : Consumed. Grms. Excreted in urine and dung. Grms. Retained. Grms. Per cent. Total ash 81.34 25.34 8.85 19.13 1.80 20.70 5.57 0.15 37.20 6.53 8.30 0.38 1.08 15.58 4.16 0.10 44.14 18.81 0.55 18.75 0.72 4.49 1.41 0.05 54.30 Phosphoric acid Chlorine 74.23 6.22 Lime o Magnesia 98.00 40.00 Potash 22 37 Soda 25.31 Iron 33 33 The large amounts of lime and phosphoric acid retained in the body are specially noteworthy. These substances are the chief inorganic ingredients of bone, and their almost entire retention, particularly that of the lime, in the above experiment, indicates the importance of an abundant sup- ply of these ingredients in the food of growing animals. Soxhlet remarks that it would seem that the milk of our cattle is so poor in lime that it contains barely enough to supply the wants of the young animal, and that it may be advisable to help out the supply by the addition of chalk (carbonate of lime). This would answer the pur- pose of supplying material for bone-building as well as the more costly phosphate of lime, since, according to the above results, a lack of phosphoric acid is not to be feared. 19* 442 MANUAL OF CATTLE-FEEDING. 22. Calves. In the foregoing pages we have endeavored to deduce, from experiments on calves, some principles which may serve as the groundwork for practical conclusions. The data for this are, indeed, scanty, and the whole subject of the feeding of young animals needs accurate scientific in- vestigation. At the same time, we know enough to enable us to deduce some useful hints and indications. Before 'weaning, milk usually forms the chief or only fodder. For the first few days after birth it is espe- cially important that the calf have the milk of its own mother. The so-called colostrum (p. 416) has an essentially different composition fi*om the milk produced later, con- taining far more dry matter and considerable albumin, while the amounts of fat and sugar are relatively less ; the nutritive ratio is narrower, and the digestibility apparently greater. These differences nearly disappear in the course of a week (sooner in cows yielding much milk than in those yielding little), and after this it is a matter of indifference, so far as the nutritive effect is concerned, whether the calf be fed from its own mother or not. Nutritive Ratio. — That a milk diet is capable of supply- ing material for rapid growth is matter of common expe- rience, and is illustrated by the experiments of the preced- ing section. The comparatively narrow nutritive ratio of good milk does not cause that waste of protein which it would in mature animals, and the calf is thus enabled to consume relatively large quantities of this most important of all nutrients in a small bulk, and thus to supply the body with abundance of material for growth. It would seem from some experiments, however, that MANCTAL OF CATTLE-FEEDING. 443 the nutritive ratio may in some cases be advantageously made wider, especially if tlie milk is very rich. In some experiments made long ago in Saxony,* three calves, four- teen days old, and weighing 117, 130, and 114 lbs., were fed daily as follows: Ko. 1 with 13.2 lbs. cow's milk and 13.2 lbs. whey ; No. 2 with 22 lbs. of skimmed milk ; and No. 3 with 17.6 lbs. milk and 3.9 lbs. cream. The average consumption and the gain in weight per day were as follows : Consumed. Nutritive Ratio, t 1 : Gain per clay. Lbs. Pounds of Organic Substance. Lbs. Protein. Lbs. Sugar. Lbs. Fat. Lbs. 0.51 matter to 1 lb. of growth. No. 1... 2.3 0.54 1.29 4.8 1.88 1.35 No. 2 2.0 0.70 1.02 0.22 2.2 1.14 1.88 No. 3... 3.0 0.73 1.02 1.22 5.6 3.38 0.97 It will be seen that the gain in weight was strikingly different, according to the food used. The least gaui was made in the second experiment, where the nutritive ratio was very narrow. In this case there is little doubt that, in spite of the comparatively small protein consumption of young animals, a considera- ble waste of protein must have taken place, resulting in a small gain. * Wolff : " Landwirthschaftliche Fiitterungslehre," p. 152. f In calculating the nutritive ratio, the fat has been converted into its ''starch-equivalent" by multiplying it by 2.5. The milk used in these experiments was rather rich in nitrogen and poor in fat. With more average milk, the nutritive ratio in No. 1 and No. 3 would have been still wider. 444 MANUAL OF CATTLE-FEEDING. In the third experiment the food was the same as in the second, with the addition of a pound of fat per day. This addition of fat evidently rendered the protein consumption less, while also supplying more material for fat formation, and, as a result, a very marked gain was produced. The amount of organic matter required to produce a gain of one pound was also less in this case than in either of the others, and somewhat less than in Soxhlet's experiments. A comparison of the first and second experiments is es- pecially instructive. The total amount of nutritive matters consumed in the two cases w^as about the same, but the wider nutritive ratio of the first experiment caused a greater and more economical gain. Sugar in Place of Fat. — The first of the above ex- periments is particularly interesting as showing that a satisfactory gain may be brought about by a ration com- paratively poor in protein, but having a rather wide nutri- tive ratio, and also that sugar may be advantageously used instead of the more costly fat to produce this wider nutri- tive ratio. This result is of practical value, because it seems to indicate quite clearly that even with pretty young calves a portion of the milk, perhaps half, may be replaced by whey,* or perhaps that skimmed milk,f with the addi- tion of sugar or starch, may be used instead of whole milk. It is questionable, however, whether the fat of the milk can be w^holly replaced by carbhydrates with safety. Fat * In the manufacture of cheese, most of the casein and fat are re- moved from the milk in the curd, while the whey contains nearly all of the milk-sugar, together with a little fat and protein. (See Table of Composition of Feeding-stufFs in Appendix. ) f Skimmed milk has lost chiefly fat, which, on the a,bove plan, would be replaced, at least to a certain extent, by starch or sugar. MANUAL OF CATTLE-FEEDING. 445 is the most concentrated of all the non-nitrogenous nutri* ents, and m the finely divided state in which it exists in milk is probably very easily digestible by the young ani- mal. In addition to this, the greater palatability of nor- mal milk is an important factor in determining the effect of feeding, as has already been explained in connection with other fodders. Whole milk is the natural fodder of young animals, and the one whose composition must be imitated as closely as possible in all attempts to substitute other materials for it, and w4iicli, for the first two weeks at least, should, if possible, form the only food. During the first four to six weeks, an mcrease of 1 lb. live-weight is obtained, on the average, with about 10 lbs. of milk (1.25 lb. dry organic matter). At first the quantity of milk is a little less, and toward the close a little more. Since, however, the composition of milk is variable, the amount of fat, especially, varying from 2 to 5 per cent., and the nutritive ratio consequently from 1 : 3.3 to 1 : 5.5, it is easy to see why the effect produced by the same quantity of milk should vary considerably in different cases. Substitutes for Milk. — It is sometimes desirable to replace the milk partly or wholly by other feeding- stuffs. In doing this, it should be the aim to compound a ration approaching milk as closely as possible, not only in com- position, but also (and this is quite as important) in prop- erties. It should be easily digestible, liquid if possible, and should be fed warm. This is not the place to enter into a discussion of the various substitutes for milk which have been proposed. It is om* office simply to point out the principle on which they should be based, viz., as close an imitation of the composition and properties of normal milk as possible. The tables of the composition and digestibility of feed- 446 MANUAL OF CATTLE-FEEDING. ing-stuffs contained in the Appendix will aid in forming a judgment as to how far these conditions are fullilled in any proposed substitute, while actual trial alone can fix its tiiie practical value. Weaning. — It is one of the feeders chief problems to bring about the change from exclusive milk feeding to other fodder in such a manner as not only to cause no fall- ing off in the condition of the animal, but so that a con- stant increase in the live-weight shall take place during, or at least immediately after weaning. This can only be accomplished by making the change as gradual as possible and replacing the milk by substitutes of suitable digesti- bility, palatability, and nutritive quality. Crushed and boiled flaxseed is at first very well suited to this purpose. Later, oil cake or palm-nut cake, and also oats, barley, malt sprouts, etc., can be profitably used, w^hile by feeding the finest and tenderest hay the animals are gradually ac- customed to coarse fodder. When the calves can be early put upon good pasturage the weaning will accomplish itself ; but where this is not the case and they must be stall-fed, more care is demanded. At first the same nutritive ratio should be maintained as in average milk, or, at most, it may be a little widened to- ward the end of the weaning. The fat of the milk, how- ever, may be pretty rapidly replaced by a corresponding quantity of easily digestible carbhydrates, without, how- ever, making the change too sudden. In this way the complete weaning of the calves may be accomplished by the end of the ninth or tenth week, or even earlier. After Weaning. — After weaning it is advisable to con- tinue for some time the use of quite concentrated food with a nutritive ratio of 1 : 5— 6. Soxhlet's experiments (p. 439) render it probable that MANUAL OF CATTLE-FEEDING. 447 all young and growing animals utilize a larger proportion of the protein of their food than mature animals, and only lose this power gradually as they approach maturity. A growing animal, then, may economically i-eceive a relative- ly large proportion of protein, thus placing at its disposal an abundance of material for forming new tissue, while as it grows older either the amount nnist be decreased or more non-nitrogenous nutrients must be added to the ra- tion in order to protect the protein from waste, i. -0«OTf b-MJOWi (N C* Ci OJ »-i' T-t i-i r-i r-t tH i-< »-«* r-i O T-i rH »-; 1-; i-i T-; r4 1 105 CO O CC ^ P !^ •aSBJOAV •miuiyj; •83Ba8AV •UIIXKJ\[ •uiiuiH OrHOrHlO^OWO •00>rOOt«-0«00'»J<>00>t«THOOo t-.' d c>-' «o tjJ co d c-: ■* Tji d oi o -r in coo o in"CiO: ussoo ;offl t- o: or «D i-I x5 1-^ ;o i- !-■ w cj 00 id • o c-' t-^ od icJ »d ad r-f o6 -ojo tH00OO^5«<»50 i-HOiOOOO-^ :050CD«005cq«OiO •.!C»o ec t" X 1-' ."o id cc CO ?3«CiJo»drH • eo cc ■^' t^ cc T-i -^ tj! eo -eod tH iH 0> t- >0 O t^ CO « « -"j* >0 O W ,H tH (O O ■* -* >0 « -H 00 «0 C^ i-l CO N ■*■ rH 00 00* id «' o> oo' CO oo' c* *d «d o od « ci cj od co n r*' CO 05 cc "^ th CO -n; -^ (w IN tf> »n in o: 1-* od (T* Tl 1-1 r-i r-l ;qoo5co ; t-_ iq X o oj 'N c« c* 00 :0;C> " d X t-- • ■?»' d x' -r ifi cj d d d • oo' «♦ if5«o;OTrc*c>«i-ir-t c^ooc^i-ho ;iooT-D ;io»o cciT-Icox''o 1 1^ r* 00 c»- >o Orioddddo O O O O O O O O O O O O O rH iH O m . -i-ii-H ca C: C5 1-_ CO c: C5 Oi 1 ,H ; ,-< 1-J t-i d d d d d d d 1 CO . ■ -"s^ GO iq CD -^ O'OiOOr-(00t>.>O'#M'^rH«O-«lt0»r00><0 CO CO d CNJ fo ■*■ d CO ei co rf CO CO CO «' CO CO* oi co' r-i 1-i M Tji ei co ej ci oco-^off*ioc>i- xt-cowtoc* ;t-^05T-(!0(r*mxosec I'-J'^ co«Doo;(NOt-;'Tr ■»i«c*X(?<»'i] ;t-_c*XtHS5Xt-;iqas ;t-.^ r-(- V) o CO c>- o >o eq o o iH 00 c~ 00 lo o CO •V (T* CO TT CO rH.>o i^jt'OrH ^_ rHooeq t** c o co" 00* 00 pooor»iocq ^' >o oo' oi ai vd i> o» CO >o' CO cq •<# rH rH 00 -H -.t o\ o 00 fo CO o> 'if 00 tj( co d «o" oJ od o' «d ^ d -»i-*Tpvco'^T*i.^Tj(Tji-O0000Tj«00O'^>O d d d d d d d i-i d tn C0\OrHt^V0r»Ot««00f0W*'-"M0000«O0> CJ co' CO M N iH n' rH* rH « (N CJ c6 CO ff Co' CO CJ •N'OCO : CO COM S'O'OO CO n' ci CO cDOs-^coc^oo ; >o rH CO rH CO »o rH ; ; ; la to -^ iO c6 (^ oi ■ (W TO CO 03 CD id C* ; • ; eOrHt- • TO'idTO- : TO CO TOGO : : 0303 ; ; n : :- :-^. : : : O ; ;0 ;00 ; ; ; 0 00 (0 Ok CO Ot (N eg cq M CO rn n cj « ci -o •O'OOrlKOCq'OOCOaTilH^OOrOCflCO 0>' 3 d C?; O; «V' l> t>' d t>' ©■ rH r-i rH 00 O 3" rH rH rH t-i r-t r^ r^i ri t-i .^O>0O Ch rH'.f CO r» co(N :m leoeo : :oo" Tf tH 0» 0» 00 ■<3' O ■ O 'J" -* 20 m O) *J • . • o: id r-; ^" TT 30 05 •o:Trdt^co*ld-^» : : : r-l (N rH rH r-l . rl rl rl rl rH . . 00 TO 05 idoo't^-i< 00 to' 21.1 19.7 17.1 14.0 Tf .'irw .lain . .00 1-; '.oici '-rioi : :c« 00 00 rH rH ir» 05 O • O O CD TO_ "^ o o o -o o d rH Tjt' d or»t^r»t^ococ»{Ot^ooo • ocoo o\ s 84.8 83.8 85.1 84 b o bo o ^S |S §* 480 MANUAL OF CATTLE-FEEDING. 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O M OS •aSBJ8AV a CO rH « CO o c«. o r» t> d r-i iH iH ei iH OC iH rH O o.l •rapcBjg; •oSBjaAV •UIIXBpi -000>'00*OOC*r.t».O^i-jMMO00«OrHr» CO* rH CQ rH i-f CQ i-« CO* C] oi O M O •UIIXBK •raiuiK odd ^ 'T o ■^* t-* : od ; 00 i-H o ■^* e<3 od cdoddt-^ -d -dcidiridi-^ •aSeaaAy 0<000»'*_tH >o rn >o* ci >o* 00 1>.* •-< of rH iH i-liH iH i-l rHC0C4 00 00 O 00 00 0( 00 0\ 00 00 00 0> CO •IUIXBJ\[ •miuii\[ cct-(N : ;coos ■^ w d • " d CO* 05 05 ^ OS "OS CO 00O>t-t- :i-t [to !0 to y-t a> dco*:^TH "d 'cst^t^ai-p 00 00000000 -t- -ooooi- St 2 a £ S a Ph<'-i MATTTJAL OF CATTLE-FEEDIl^G. 483 ooqcooo1-^TJ<^-cq^o<^»^--^Tj1-3 -^ W t-^ r-i 00 i-i T-1 rH r-i 1^" O o" tH O T-^ a <» © Ol O Tjt ^ t>- a 00 Ol t«. t*. i-t Oi O rH >0 CO O 0\ ■* rH 0( O 00 CO 0> C«- O rf iH o\ iH o "O o' o eo ov >o* ci ■* d ■* d 05 T-j c: 1-1 : id i-i iri i-I eo* -^rAn eo -^ • ••ineo^05eo •-rnc^eo • -oio rH «0 I ; O Co' T-i eo" Co' t-h' 00 Tji ; CO CO O ! ; CO JO • ecco •05350050 I-050 tH cj ovqoio ^«^ONOl N oco^« io o^M^« N<>co(N 00 o c^ oorHi-i © co d CO 00 vd o> vd csi c~-' CO* o> vd o> co' t> o\ d i-i co' i-i vd t> ■<<* o\ 00 >o' co rw >d id co* "d ■o -^ 10 Tf >o M CO T}< lo eo rH T-< cq eg i-t (N co >o co »o ■^ ih th rH t» »f3 iH • • CD Tf CO 00 OJ TJ< 00 10 'OOt-O :t-^O3Q0O5Q0 0O • c^Teoinco'-^cD id w *«' QO CO i OS • • iH 00 C5 C5 'T OJ t- 1-1 •l-HO'^ ; t- o» CO »o T-H t- :^'o-r'r-^eoTji' COtHtT Tft-'cD CD ov ?2 00 CO <0 10 <0 CO rH (O CO CO >0 CO >0 >0 10 UD 00 CM d eg CO i- • •l-«500OC00500'^ -lOOO CO : '.oioiiacooit^cc-rA 'oig^'ig • t-eo»o .corr • 10 ■.'^. : : : .0 , . . rl -00 I- :d 00 CD r-i ; • 05 (N CO (N 1- CO CO "ot-o « : jd^'dr^r^CO^'rH- ; .d rH CD •OC005 -CSCD :!? :«^ : : : •d ; • • t- -CD jd CO CO r-J *^ '^ "? 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"*. o» "^ ■* ^ "o. o> 00 o ov M* o\ t^ d >d eg t>' co' o' 00' -h 00' eg' r-i a\ 00 •* /o cq o o CO CO eg efl » o Ov CO t^ CO «o 00 " c>.' eg rH eg co' o> >d d rH rH >o' (d d >d co' 00 0\ Ov 0\ (J> ■<1< CO >0 00 >0 rH rH rH rH ) rH O 00 CO O 00 ) T-J rH 00" d 00' d ) 05 05 00 C5 00 00 ;»nco •00 00 •looo ;cocD00rH»co • rH 06 i^ r-! t-' id S!^?! ; ^coeooic^io-^oc* • * Tf d t^ •^ id oj 00' d • •oococ-cooooot-i- dr-Jd ;oo ; ;oo'i;o'^-^o • ^ 2 ■ • d co' '^' id id w .■TJIQO • -OrHrH rH C^rHrH H Si « a >sa a 3^ .s- ^ ^^1 a : -^^ s .'^^-s-g « 10 Ot JO) ; to • --^ J g c ^ ar s - . ^ it D cSw.S I :' ^ i 484 MANUAL OF CATTLE-FEEDING. •33BJaAy •raixejij •inimiv i-i -t*.' : •r^■oo q -"jf c^ 00 00 >o o\ ■H CO oi 00 00 .H c4 ■V00t^«C*'ooo\ CO i-i 00 r^ Tj< o\ ci < o>' ■*' o»' ^' vd "o >-"(_. . . cgfoo CO r* o CO ' i 0\ ,H i-h' ts.* o oooco(MOv>ocoiO'*ooo i' n' V CO CO 00 00 00 l> t"' 00 o 1-1 • -JO ^crioTOT XI ; T-< ri c: t- -* ; :oto O • r-i :r O r-1 O • -XOi t>.qi> t^caoco i-i co' N t> "d oo' ci » <> N o» «o >o vq o CO c!i iH ■* r> >o »-i co' oi o\ eg >H o' vd co' oo' o' .-i lo' oo' t<-' c4 oi co' CO CO Cl N CO CO CO t-( tH rH M CO Tf r-l CO rH rH Ifl X X CS rl X -r t- 1-1 c^ (W 5< c« ** ( Q « •aScaaAy •tniniK 00 <0 (SJ o o \o ooo<0r^c^voe^foo»'0r-noe^ CO «: *»' T^' o iri 2/ -2 • CO 1" (M* ■?» o C5 c; s: Ci cv ~. c; c; • c; ci cr. c; ci ;tc5 ■ coo ■xo» XXOOXXOOXOO •OOOOCOXl" • 'XQO fl ss: •sis -53* rr ^ c3 O ;2 « III X o ci='.S -(SX.S Xoa^sS XO« 2 o fl 01 i: O MANUAL OF CATTLE-FEEDING. 485 Qo to o» (N in t- c* t- :c 00 CO eo 5* t-_ ; -^^ «> «o lo >n to » CCiri»r5eOC-^tOi;OCOO:i.'i--i(?*t-"^T-i'o'!tr-i"oOOOi-i lOfOrHO r-' m CO o» r*CftMf0(0>0C0f0rHI0C^C<.f0MO>OTj.' CO t>' o»" ■*■ o{ r^■ i> ■o tn o rn o h m rH >Ol-lrHrHrHrO r-H i-l o«o eg© '^. : CO ' 00 0» CO CO IOCOICtH .t-OOlW O«*10tH •IOCS •OOI^COM loteo ; T-H »-i r-i r-i i (NOO «0 ; l-HCO'Tl-H cood-O 00«t-l00-*TfO0»C~rHt-.I>TH'O0\VC)*0OV0f0 0\0 th CO c-' Tji Tjt (o cq i> i> r-t t-^ oi cd fi o\ co" ■o ^ *o ■^ vo "O «o • CO CO CO ICON 'i'COCOMOrHrHMCarHrH . C^ O O O iH O • oi 35 co' »o CO o -^ lo «ri i?{ • co' iri CO »o 1-i '• g< -^ • 0 0» 0>OV0<0 I>»0>Ot<.'000(Oi-t^i-ICOTj«CJC3>VOCOrHrH'<<<0\00»00 COM -"l*.-! g* •oco'co'd ei©-*-*' cd ^r ^' ■o' ■* Tj* i-lrH rH-HHiH tH i-l H CM N M § • -COCO -^xiNO Wt-ii-ioo •oocoTHtcioiflio'^ -wos -loosi-io -o r-ia* com ^ I looco doo'o't^ -q'co'ocJd I -"^ eo co' iC -^ d d !r» ;d«o ! eo r-i (N (N Ico' th'o do „ • .(Nt- '. Ico'd 41.5 3.5 12.6 10.1 rHQOrHtO -OOt-THOOOOOOt- .05i- . I- 00 O 05 . C« dcodc* :a)o*r-;eo*co*dooeo '.oi^ Imo'ih't-; ItA tc«o dw coo w'^ t~oooo ONHO O 00 00 CO >0'O'OTjli0t«t»C0O0\O»0<3>o d -q! d oot-crsoooo oin dd 05t- •oin •coooeoco C005 lOICJ r .e'S's'e S S S 2 cj ' Sc:s 0) 0/ a P o 'S£.5, i- c;-5^ : ._^ j3 jC , i •oSvjdAY >T>« iH H •raixBK d : d rdddT-i'^'i-Jr-leo Ico rjJ : j « w r-i . o .ooiccooc«i-ic>» .eo CO • • •luiniH d ; d ;dT-i(?»d?Dddr-; It-' T-i ; ; e ?i^ o o> *O00O> Mt^>0.-t00 OOOOO OOOOt •8SBJ3AY H d dd d CO CO co>o' CO rHNoi 00 ■0>(N«0-> 1 •niTuiM <=> O OOC0l0t-O(NC*-T^ --rH «D :o OT >o iOQdQdddi^c/.>ciirid -tc §8- :^ •.i • C • • Jh • o a a> ND BEFUSE. from cent machines, from diffusi ss, fresh... 1 : : ^ o ]-H «3 §) * +- VCTBA ake . . . esidue fugal esidue proce nted.. :& :"-?i "o g Q'^'' ^ c^^°° • • « lis ll= s|= = i^i-liliiii CC Cfi P^ CG op; > f-i^^^ W 1 MANUAL OF CATTLE-FEEDING. 487 •93B.iaAy •raiuin W M O M •aSBjaAy 'unx'Bjj; •aSBaaAy •UIIX'EJ^ •aSBjaAy •UIIXT3J^ C? GO Ttl Tt< C"? 00 CO «^ oq : CO tJ< 05 r-( C5 rhi CO o lo o o ci o CO l- O CO lO lO ^ CO 05 ,H « '-: : rs\ 1-1 t- 'i^ ■* »0 (Ti —I «0 O coooi gg^^ »o t-o«oococo ,-1 io«^W • .-I Pf CO -* I- (V< (^ *" «J O .-lOlO -- ,^ lO l-l T-J 00 «D ^ 01 CO CI O 00 L- 1- 1- TtH t- ->o in CO l> l> CO CO (M CO Oi ^ CO Tji <© O O i> i> i^ t- r> t- <© OJCOOt-. ogcogfS O C5 l> O 1-H '^H O t- O I- l> t- o o 05I>pC3 t- 1- "^ '^ a is _ t3 '-' O aa biDC -S 'g-S 0) fe Oi o aJ ra CO " C3 «J CS tD > o"S -^ ■»- -^^ .s J3 g •§ .S 1« N -gj^ III » 1"^ i 03o -J •t5 -R CD •o.S g . 0° -U Cfi jj >,z± "^ O i KfH •aSBJaAY •niixBK •niimn eScjaAY •raiuiH •aSBaaAy ■niixBK ■<*000005C? looo wo § SI t-o»-*coco "3 ifS ri C5 3d ci s coaooooo^ : : : oaooccrs CO lo ■*■ ^' T-^ »rJ o • • • « r-i in i> in l> O 00 t- I- I- CO • • • b.l-1-OO oinooot-ic : : CD»0«©CCCC ^o^^oog^oo oo-^oo _§. t- O O O O rf CO ci 0? CO ifi r-5 j> »o CO x* ;0 (^ O lO t- ;-*GOco •i>ioo lOTtiOOOOO t- 'i-nOift •aSBJ8AY •raixBjv ■oiraiH o CO o o o o CO : : 1-5 00 OJ CO* !>■ 00 CO • • t>. {© t- i;D iC O t- • • O O CI o t- .g CO I> d O irf a, 00 i> I- » I- S OStHOOOOO CO Tj5 -J? ci CJ CO CO CO lo lo Tt< Tti o ■* r-ICOt-OO • a, : a • o . OB O) r !>- ^ '^ Hi += "aJ s !- 5 P4 OQ Eh - o a r-( O MANUAL OF CATTLE- FEEDING. 489 St-O T-J CO so CJ T-< OJ iO 5D O CC O lO ^5 ss o o5Ss i : 'OSOSDOOiO : T-4 I : • 00 O 1-1 O (M OJ (MCOrHlOSOCO ^ 5: •; • :soooooso!> CO ,-3 00 ■ : • so -+< 00 O CO ■* o bo's *^ ^ a (!)•« "43 -^ ^ o '^ s '= & c3^ ^ -. -. ^ - o s ■« "^ >< * o ® o^ >> n2 > -rt e; p 5; «■ ^ Q o^o i3 Oj i- ^ 21* "> "S i S c: "^ bc^ a, o p 5 s ;3 111! ° I §•'' g "S S rt 3 O 5P a aj .3 490 MANUAL OF CATTLE-FEEDING. •bStsxsay f.?^?. ^ § 8S 8^ ^J^'^^^S SSSif? ^?;; o :■*■*(» :o(N»o COWlftOS ooo»(M »o : •raixBH ^ :S^"^S :|8^' ^■"^^^' §§^g? ^' : o -.tJ^oo :rHao^ oo :i> (Ml>r-i05 lO ; o •ranijK :^^§ :^^!§ ■B ^j^t^co eo : ^5 •aStsaaAY ^S8^S^^g§^8 essp SS'^8 J?3g i^ O :cCCOTt< :t-lO:DO O5-*C0t- O (M I* O ■*■ 00 CO i-< • O C5 GO GO CO 0l>l>05 00 • Pk T-H 1—1 t- 'OOiO •Ol>'*iC COCONO 0l>-*0> «D t 05 • Tji CO l> • O CO 'T »rf ,-; irf o o lowoici -; • t- '^OOt- -COCOOOCS 00 CD 00 GO ' ^ h : :j| : : ; o a o ■■■mw i il S 1 a 1. • 1^1 is si 11 o s o &x « o^ j; o ;> p O a: O bc ' 5 §= = -- CD 5 O -ta G 0) • ^ EC p -5- - - X^'T3 o c ?^ g- :: - :: - i i 2 5 c 4 a ' a. - a 1 1-^ ■ t 1: ;3 11 1*1 MANUAL OF CATTLE-FEEDING. 491 OS ^ Tfiooo? ; I lo ( OiC-000» 1^ i : : : : : : cow :;::::: »-!■*•• cot- in COI>OOlOOOl>«00 OOlOCOOOOSOiOOt-O .f, . . . :8 : : : t-CO00COC5O>O5OSi;Dt- 492 MANUAL OF CATTLE-FEEDING. Table IIL— FEEDING STANDARDS, A. — Per Day and Per 1,000 Lbs. Live-weight. Nutritive (Digesti- ble) Substances. a g « t> > Is •1 •l 1 c^ o-S S S S ^ _J S H < o ^ H 1. Oxen at rest in stall 2. Wool sheep, coarser breeds " " finer breeds. . 3. Oxen moderately worked. " heavily worked 4. Horses moderately worked. '' heavily worked... 5. Milk cows 6. Fattening oxen, 1 st period '^ 2d " 7. Fattening sheep, 1st period 8. 10, 11, Fattening swine, 1st period u 2d a 3(j u Growing cattle : Age. Average live-weight, months. per head. 2-3 .... 150 lbs.*.... 3-6 .... 300 '' .... 6-12 .... 500 " 12-18 .... 700 " 18-24 .... 850 " Growing sheep : 5-6 .... 56 lbs.* 6-8 .... 67 '' 8-11 .... 75 " 11-15 .... 82 '' 15-20 .... 85 '^ Growing fat pigs : 2-3 .... 501bs.* 3-5 .... 100 '' 5-6 .... 125 " 6-8 .... 170 " 8-12 .... 250 '' Lbs. Lbs. 17.5 0.7 20.0 1.2 22.5 1.5 24.0 1.6 26.0 2.4 22.5 1.8 25.5 2.8 24.0 2.5 27.0 2.5 26.0 3.0 25.0 2.7 26.0 3.0 25.0 3.5 36.0 5.0 31.0 4.0 23.5 2.7 22.0 4.0 23.4 3.2 24.0 2.5 24.0 2.0 24.0 1.6 28.0 3.2 25 2.7 23.0 2.1 22.5 1.7 22.0 1.4 42.0 7.5 34.0 5.0 31.5 4.3 270 3.4 21.0 2.5 13.8 13.5 13.5 13 12.0 15.6 13 3 11.4 10.9 10.4 2.0 1.0 0.6 0.4 0.3 0.8 0.6 0.5 0.4 0.3 30.0 25.0 23.7 204 16.2 Lbs. 8.85 11.70 13.15 13.20 16.10 13.60 17.00 15.40 18.00 18.50 18.10 18.70 18.50 32.50 28.00 20.20 19.8 177 16.6 15.4 13.9 19.6 16.6 14.0 13.0 12.1 37.5 30.0 28.0 23.8 18.7 * See note on opposite page. MANUAL OF CATTLE-FEEDING. 493 Table III. — Continued. B. — Per Day and Per Head, li 1 NuTRiTivK (Digesti- ble) Substances. fi \ / 1 ."2 o B a < i 1 •2 Growing cattle : Age, Average live-weight, months. per head. 2-3 .... 150 lbs.* 3-6 .... 300 " 6-12 .... 500 " 12-18 .... 700 " 18-24 .... 850 " Growing sheep : 5-6 .... 561bs.* 6-8 .... 67 '' 8-11 .... 75 " 11-15 .... 82 " 15-20 .... 85 " ...... Growing fat swine : 2-3 .... 50 lbs.* 3-5 .... 100 '' 5-6 .... 125 " 6-8 .... 170 '' 8-12 .... 250 " Lbs. 3.3 7.0 12.0 16.8 20.4 1.6 1.7 1.7 1.8 1.9 2.1 3.4 3.9 4.6 5.2 Lbs. 0.6 1.0 1.3 1.4 1.4 0.18 0.17 0.16 0.14 0.12 0.38 0.50 0.54 0.58 0.62 Lbs. 2.1 4.1 6.8 9.1 10.3 0.87 0.85 0.85 0.89 0.88 Lbs. 0.30 0.30 0.30 0.28 0.26 0.045 0.040 0.037 0.032 0.025 Lbs. 3.00 5.40 8.40 10.78 11.96 1.095 1.060 1.047 1.062 1.047 1.88 3.00 3.50 4.05 4.67 1 4.7 5.0 6.0 7.0 8.0 5.5 5.5 6.0 7.0 8.0 1.50 2.50 2.96 3.47 4.05 4.0 5.0 5.5 6.0 6.5 * The German pound is equal to 1 Vio lb. avoirdupois. The above weights are therefore to be increased i/m to represent our weights. For practical purposes, however, this reduction will be in most cases unnecessary, as tlie weights are but relative and approxi- mate. The quantities of nutrients calculated per 1,000 pounds live-weight, of course, need no reduction, being simply relative, and the aame is true to a certain extent of the quantities per head. 494 MANUAL OF CATTLE-FEEDING. •?BJ •paj-lPM •JBJ ^JOA •^^d •?«J Jl«H •paj-IPAi. •OBai •JIBO ;b J •;«i •?BJ Jl^H •P9j-n8i^ ! o o o rH : o o « oj ci o t3 9« .UHOirii^ . C? (M 05 1 '. o o -^ cj : o ,-; CO . ■8 9^'. 00 «00 ( CO di-Ji-Ho'doii-i" ■g o?o o coo fc, tJ^CO CO '^Tj' ■g O Oi CO t- iO O 1—1 P^ t'. Ti;Tti»o •cJdddrHddwi-;^ 0} r**l>- Ifi ■*■ t-" rH .t-OiCt-COiOOIOiftOi t-i-i : ej d d d 1-; d d CO r4 oj "f cq -g O t-'*Oi 2 00 ^" 00 i-i «T3 OOOtit-i-OlrtOJiCOCO -^^ ci d d d rH d d -* oqi ci t;;! ■ fl J, • c8 03 OJ S i^ tc r: C eg O :3 ;^ K H K h5 H? (^ aaa2 m ^ S MANTJAL OF CATTLE-FEEDING. 495 r-iCOi-lO rfi GO «d:d CO C-' ci i> W t-' GO irf OCOrJIOiiO I. CO CO O ^ rH 0(MiCtHO ^OO^Gd 2 OlCt'OGO o § .-iOJOTt W rH CO CO O CO IC « -# M 05 »0 05 IN O i-i t> iC »o irf i> TjH M ^" OO t OCOOSiCOi 00 1> t-^ !?i oi .CO OTfiooco «d i> (?} 05 ci CO Q S rt cot- CO -*co coco J>00 o«o 00 ci 00* 'l^" CO Spq^ph O iOiO00lOTji M 4;) O pd 496 MANUAL OF CATTLE-FEEDING. ■?«J ^99 r O 8 cooes C5 ci ^ -; TO o 8 o o o o d • o d •pajiPM 1^ o 1 o s T-H CJOCS05 o 1 O »C IC IC O • IC rH r-5 d c> d Id 0? CQ •?BJ XJOA tj9R ■*c?^co i-J N* CO vi o 8 T-; ,-; d d d d d ■%vd O '^ I— 1 o 8 I-l OiCicoci j-j CO CO o CO rH id o 8 ^r-;ddddd 8 oi •?«JJI«H o coooqo -Rococo o 8 r-t th t-i d d d d d 8 CO •paj-naAV m o 1 in' 1-" CO M o 8 T-I r-3,-Hddddd CO CO •uBai o 8 wcooo o ^ ^ o d d d d •JIBO -JCJ tj-19 o 8 o 8 r-: r-; d d d d d s •^«J o i iO ?D ■* O o 1 T-5 rH d d d d d 8 CO ntJj JIBH 1"- o § iCCOWO o 8 tH ^8SS^S^ r^r^ddddd ^ ■* •p3JiT3A\ -J coo |32 o i 00 05 id CO o 8 r-l r-i c J d d d d d ij : ■< . g : o . c g li •3 1 •< H i O a5 ii c '5 1 PI j3 < u 1 o 1 11 ' a .0 '5 a, C 'J 1^ c 1 '3 1 1 a o jo' o 1 1 1 INDEX. Abomasum, 57 Accidental salts, essential and, 23 Action of bile on the food, G3 pancreatic juice on carbhydratea, 63 fats, 63 ptyalin on starch, 56 saliva on the food, 56 trypsin on albuminoids, 63 Acd, carbonic, effect of work on excretion of, 206 excretion of, by young animals, 440 glycocholic, 62 hippuric, 84, 93 formed from albuminoids, 87 hyoglycocholic, 62 lactic, 13 metapectic, 46 muriatic, 59 phosphoric, excretion of, by herbivora, 258 during work, 208 sarkolactic, 13 sulphuric, excretion of, during work, 208 taurocholic, 62 uric, 93 Advantages of ensilage, 317 ^sophogean demi canal, 57 Age of animals, effect of, on digestion, 270 Agriculture, objects of, 1 Albumin, animal, 16 properties of, 16 vegetable, 27 498 INDEX. Albuminoids, action of trypsin on, 63 animal, 15 composition of, 17 decompositions of, in body, 87 determination of, 48 effect of gastric juice on, 59 on digestibility of coarse fodder, 275 errors in determination of, 49 formation of fat from, 87, 171 gain of fat aided by, 178 importance of, 33 of milk, sources of, 418 vegetable, 2G comparative value in nutrition, 31 occurrence, 33 Alimentary canal, 55 Alkaloids, 35 of lupines, 35, 310, 343 Amides, 35 by action of trypsin, 63, 163 decomposed in body, 159 determination of, 49 digestibility of, 257 feeding standards affected by, 371 functions of, in plant, 36 indications of nutritive value of, 163 in malt sprouts, 341 nutritive value of, 158 Amido-acids, 35 Amines, 35 Ammonia, excretion of, in respiration, 101 salts in plants, 34 Amount of drink, 238 protein necessary to sustain life, 132 Analysis, fodder, 48 Animal albuminoids, 15 composition of, 17 occurrence of, 15 properties of, 15 varieties of, 15 body, composition of, 5, 365 INDEX. 499 Animal body, composition of dry matter of, 10 inorganic matters of, 20 nitrogenous constituents of, 14 non-nitrogenous constituents of, 7 casein, 17 fats, composition of, 12 heat, 83, 229 nutrition, general laws of, 3, 5 products as fodder, 349 Anterior aorta, 78 Aorta, 78 anterior, 78 posterior, 78 Aqueous extract as measure of digestibility, 253 Arteries, 78 Artery, pulmonary, 77 Artichokes, 361 Ash, determination of, in fodders, 50 digestibility of, 258 Asparagin, 35 a nutrient, 1 63 functions of, in plants, 36 nearly equivalent to protein, 166 nutritive action of, 165 Auricles of heart, 77 Average composition of nitrogenous constituents of body, 19 Barley, 334 digestibility of, 335 Best time for cutting clover, 303 hay, 293 Bile, 61 action of, on food, 62 Bilirubin, 62 Biliverdin, 62 Bleeding, influence of, in fattening, 200 Blood, 74 amount of hfemoglobin in, 200 coagulation of, 76 corpuscles, 74 fibrin, 16, 76 500 INDEX. Blood plasma, 74, 75 composition of, 75 serum, 76 sugar in, 13, 76 vessels of intestines, 68 Body, components of, 5, 365 materials of, constantly decomposed, 2 Body-fat, influence of, on production of fat, 198 protected by fat of food, 187 protein of food, 188 Bokhara clover, 312 Bones, proportion of, in body, 6 Bran, 338 composition of, 339 digestibility of, 339 Breed, influence of, on digestion, 269 Brewers' grains, 339 Brown hay, 317, 318 Buckwheat, 335 Butter, influence of fodder on quality of, 430 Butter-fat, composition of, 430 Bye-fodders, nitrogenous, effect of, on digestibility of coarse fodder, 277 Bye-products of the grains, 337 from milk, 354 CALCUTiATiON of rations, 466 rules for, 473 Calves, feeding, 442 before weaning, 442 nutritive ratio, 442 substitutes for milk, 445 sugar in place of fat, 444 food of, after weaning, 446 weaning of, 446 Capillaries, 78 Carbhydrates, 38 act analogously to fat, 143 action of pancreatic juice on, 63 alone do not decrease protein consumption, 137 and fat, difference in action of, 192 INDEX. 601 Carbhydrates and fat, relative effect of, 194 decompositions of, in body, 88 decrease protein consumption, 150 effect of, on digestibility of coarse fodder, 280 nitrogen- free extract, 282 protein, 280 equivalent to fat, 157 fat from, 173, 394 conclusions, 186 experiments on dogs, 183 ruminants, 174 swine, 180 sources of uncertainty, 184 feeding with, alone, 136 protein and, 143, 191 may cause long-continued gain of flesh, 155 may be oxidized instead of fat, 192 mutual relations of, 44 Carbon, excretion of, 103 Carbonic acid, effect of work on excretion of, 206 excretion of, 103 excretion of, by young animals, 440 in venous blood, 81 removal from blood in lungs, 82 Casein, animal, 17, 417 gluten-, 28 composition of, 28 Cattle, fattening, 392 addition of oil to fodder of, 398 feeding standard for, 395 preliminary feeding of, 396 first period, 397 second period, 397 third period, 397 Causes of resorption, 69 Cellulose, 38 composition of, 39 determination of, 40, 50 digestibility of, 40 how digested, 64 502 INDEX. Cellulose, properties of, 38 starch-, 43 Cereals, 330 straw of, 322 Chaff, 327 Changes in nutrients during digestion, 64 Chemical changes in ensilage, 317 production of, 240 Chyme, 60 Circulation of blood, 74 pulmonary, 80 systemic, 80 Circulatory protein, 123, 125 Circumstances under which a lack of inorganic nutrients may occur, 463 Clover and clover hay, 302 Alsike, 31 1 Bokhara, 312 hay, best time for cutting, 303 effect of wetting on, 305 losses in curing, 304 period of growth of, 302 incarnate, 312 stone, 312 Swedish, 311 sweet, 312 white, 311 Coagulation of blood, 76 Coarse fodder, circumstances affecting digestibility of, 259 digestibility of, by different kinds of animals, 267 digestibility of nutrients of, 245 effect on digestibility of, of albuminoids, 275 carbhydrates, 280 concentrated fodders, 273 drying, 260 fat, 286 methods of preparing, 265 nitrogenous bye-fodders, 277 period of growth, 263 quantity eaten, 259 roots, 283 storing, 262 INDEX. 503 Coarse fodder, effect on digestibility of, of the grains, 278 Coarse fodders, the, 288 Cob, maize, 328 Colostrum, 416 Comparative value of vegetable albuminoids, 31 Compensation between crude fibre and nitrogen-free extract, 250 Components of body, 365 nitrogenous, 14 ^ non-nitrogenous, 7 Concentrated fodder, saving of work by, 228 Concentrated fodders, 330 determination of digestibility of, 273 digestibility of, 273 Conditions iDfluencing production of fat, 198 of muscular exertion, 217 Conduction and radiation of heat from skin, 231 Conglutin, 28 Consumption of food by young animals, 437 inorganic nutrients by young animals, 441 protein, 121 Cooking fodder, 239 effect of on digestibility, 265 Corn meal, exclusive feeding with, 58, 229, 378 Corpuscles, blood, 74 Cotton-seed cake, 347 digestibility of, 347 Course of nutrients after resorption, 71 Crude fat, 50 digestibility of, 254 Crude IJbre, 40 compensation between nitrogen-free extract and, 250 composition of digestible portion of, 247 determination of, 40, 50 digestibility of, 247 effect of starch on digestibility of, 281 Crude protein, 48 digestibility of, 254 formulae for digestibility of, 255 Decompositions of albuminoids in body, 87 carbhydrates in body, 88 504 INDEX. Decompositions of fat in body. 88 nutrients in body, 87 Decrease of protein consumption by fat, 138 Determination of nutritive effect of a ration, 109 Dextrine, 43 Diaphragm, 80 Diastase in pancreatic juice, 63 Digestibility, 243 aqueous extract as measure of, 253 , determination of, 104 effect of ensilage on, 320 fat on, 286 nutritive ratio on, 281 salt on, 287 of ash, 257 cellulose, 40 coarse fodder, circumstances affecting, 259 effect of albuminoids on, 275 carbhydrates on, 280 concentrated fodders on, 273 drying on, 260 fat on, 286 grains on, 278 methods of preparing on, 265 nitrogenous bye-fodders on, 277 period of growth on, 263 quantity on, 259 roots on, 283 storing on, 262 concentrated fodders, 273 determination of, 273 crude fat, 108, 254 crude fibre, 247 effect of carbhydrates on, 281 crude protein, 254 formulas for, 255 fat, 108, 254 fodder by different kinds of animals, 267 estimation of, 470 nitrogen-free extract, 249 effect of carbhydrates on, 282 INDEX. 505 Digestibility of non-protein, 257 nutrients of coarse fodder, 245 pectin, 361 phosphoric acid, 257 protein, effect of carbhydrates on, 281 Weende experiments on, 246 Digestion, 54 ease of, 65 effect of age of animals on, 270 > breed of animals on, 269 individuality on, 270 work on, 271 experiments, 104 preparatory feeding in, 105 source of error in, 106 gastric, 59 influence of proportions of nutrients on, 65 intestinal, 61 time occupied in, 105 Distillers' grains, 340 use of, 340 Distribution of oxygen through body, 83 Dried blood, 353 comparative value of protein of, 354 digestibility of, 353 Drink, amount of, 238 Drinking, influence of, on fat production, 198 protein consumption, 135 Dry matter of animal body, composition of, 10 milk, influence of fodder on composition of, 427 percentage of, 427 Drying, effect of, on digestibility, 260 Duct, thoracic, 68 Early-cut hay, non-protein in, 299 Early or late cutting of hay, 293 Ease of digestion, 65 Energy, storing up of, in body, 219 Ensilage, 291, 316 advantages of, 317 chemical changes in, 317 22 .^06 • INDEX. Ensilage, effect of, on digestibility, 320 of maize, 316 quality of product, 320 Epithelium of intestiues, 07 Equilibrium with food supply soon established, 130 rapidity with which established, 133 Equivalents, respiration, 157 Errors in determination of albuminoids, 48 sources of, in digestion experiments, 106 Esparsette, 313 Essantial and accidental salts, 22 Evaporation of water, influence of, on production of heat, 234 Exchange of gases in lungs, 81 Exclusive meal feeding, 58, 229, 378 sufficiency of, 380 Excrements, composition of solid, 73 Excretion, 93 effects of muscular exertion on, 204 of ammonia in respiration, 101 carbon, 103 carbonic acid by young animals, 440 influence of work on, 206 gaseous nitrogen, 94 during work, 208 hydrogen, 103 nitrogen, 94 earlier experiments on, 94 experiments on domestic animals, 97 influence of work on, 204 Voit's experiments on, 95 phosphoric acid by herbivora, 258 during work, 208 sulphuric acid during work, 208 water, 103 during work, 207 Expiration, 81 Extract, nitrogen-free, 51 composition of digestible portion of, 252 undigested portion of, 253 determination of, 51 INDEX. 507 F^CES, 73 Fat alone does not decrease protein conBumption, 136 carbhydrates equivalent to, 107 may be oxidized instead of, 193 conditions influencing production of, 198 consumption, influence of work on, 307 decomposition of, in body, 88 decreases protein consumption, 138 determination of, 50 production of, 111 difference in action of carbbydrates and, 192 digestibility of, 108, 354 does not replace water in fattening, 8 effect of, on digestibility of coarse fodder, 386 quantity of milk, 435 feeding with, alone, 136, 187 protein and, 137, 189 formation of, 169 formed from albuminoids, 87, 171 from carbhydrates, 173 conclusions, 186 experiments on dogs, 183 ruminants, 174 swine, 180 in fattening, 394 sources of uncertainty, 184 gain of, aided by albuminoids, 178 gain of, may accompany loss of flesh, 188 importance of, for horses, 413 "working animals, 408 may cause long continued gain of flesh, 141 occurrence of, in body, 11 of body, influence of, on production of fat, 198 protein consumption, 133 protected by protein, 188 of food a source of fat, 169 protected by protein, 189 protects body fat, 187 of milk, source of, 418 production, influence of body-fat on, 198 excessive drinking on, 198, 338 508 INDEX. Fat production, influence of muscular exertion on, 199, 326 oxygen taken up on, 199 temperature on, 198, 237 production of, by young animals, 440 proportion of, in body, 6, 13 relative effect of carbhydrates and, 194 sources of, 169 Fats, action of pancreatic juice on, 63 composition of animal, 12 vegetable, composition of, 46 occurrence of, 46 value of, 47 Fattening, 196, 392 cattle, 392 addition of oil to fodder of, 398 composition of increase of live-weight in, 9, 176 influence of bleeding on, 200 lambs, 455 preparation of fodder in, 399 sheep, 399 swine, 404 Feeding calves, 442 farm animals, 3, 365 for maintenance, 374 oxen, 374 sheep, 383 growing animals, 436 horses, 409 influence of, on growth of wool, 387 lambs, 448 milk cows, 414 oxen, 374 pigs, 408, 458 sheep, 383 standard for maintenance of oxen, 376 sheep, 387 milk cows. 431, 432 variations from, 432 standards, 365, 366 advantage of, 367, 378 affected by amides, 371 INDEX. 609 Feeding standards for fattening cattle, 395 sheep, 400 swine, 404 horses, 413 pigs, 461 working oxen, 408 limitations of, 369 Feeding-stuffs, composition and digestibility of, 3, 243 definition, 25 Feeding with carbhydrates alone, 186 fat alone, 136, 187 protein alone, 128, 188 and carbhydrates, 143, 191 fat, 137, 189 Fibrin, blood-, 16 flesh-, 16 gluten-, 29 vegetable, 29 composition of, 29 Fibrinogen, 76 Fick & Wislicenus' experiment, 216 Fish guano, or fish scrap, 351 digestibility of, 352 manurial value of, 352 Flesh, composition of, 110 determination of gain or loss of, 102, 109 Flesh-fibrin, 16 Flesh, gain of, caused by protein, 148 fat may accompany loss of, 188 laws of formation of, 110 long-continued gain of, 141 meal, 349 comparative value of protein of, 351 digestibility of, 350 proportion of, in body, 6 Fluid, intestinal, 64 Fluids, quantity of, in body, 5 Fodder analysis, 48 cooking, 339 effect of, on digestibility, 265 digestibility of, by different kinds of animals, 267 510 INDEX. Fodder, effect of, in maintaining flow of milk, 424 influence of, on composition of dry matter of milk, 427 percentage of dry matter in milk, 437 quality of butter, 430 milk, 427 quantity of milk, 419 methods of preparing, effect of, on digestibility, 365 preparation of, in fattening, 399 Fodders, coarse, 288 components of, 25 concentrated, 330 definition of, 25 estimation of composition of, 468 digestibility of, 470 Food supply, equilibrium soon established with, 130 Force, storing up of, in body, 319 value of nutrients, 315 Gain of fat aided by albuminoids, 178 may accompany loss of flesh, 188 flesh, carbhydrates may cause long-continued, 155 caused by protein, 148 fat may cause long-continued, 141 Gain or loss of flesh, determination of, 103 Gall, 61 bladder, 63 Gases, exchange of, in lungs, 81 Gastric digestion, 59 juice, 59 action of, on albuminoids, 59 Gelatigenous substances, 18 composition of, 18 Gelatin, nutritive value of, 163 Glands, Lieberkiihn's, 64 mesenteric, 68 salivary, 55 Gliadin, 30 Gluten-casein, 28 Gluten-fibrin, 29 Gluten, wheat, 28 Glycocholic acid, 63 INDEX. 511 Glycogen, 14, 81 sources of, 91, 92 Glycogenic function of liver, 89 Golden millet, 314 composition of, 314 digestibility of, 315 Grains, the, 330 bye-products of, 337 composition of, 331 effect of, on digestibility of coarse fodder, 278 value of, 330 variations in composition of, 331 Growing animals, feeding, 436 Gullet, 56 Gums, the, 44 HEMOGLOBIN, 75 amount of, in blood, 200 influence of, on production of fat, 199, 200 Hay, clover (see clover hay), 302 meadow, 288 damage to by rain, 291 early or late cutting of, 293 method of curing, 291 non-protein in, 298 early cut, 299 stage of growth of, 292 supply of plant food to, 289 variable composition of, 288 Heart, the, 77 auricles of, 77 ventricles of, 77 Heat, animal, 83, 230 applications of, in body, 231 expenditure of, in warming ingesta, 236 influence of evaporation of water on production of, 234 surrounding temperature in production of, 232 of combustion, Frankland's determinations, 216, 217 of protein, 217 production of, 229 vital, 83, 230 512 INDEX. Heat, vital, how regulated, 230 Hepatic vein, 68, 79 Herbivora, excretion of phosphoric acid by, 258 Hippuric acid, 84 formed from albuminoids, 87 Horny matters, 18 composition of, 18 Horses, digestibility of fodder by, 268 feeding of, 409 digestible nutrients, 410 Hohenheim experiments on, 410 importance of fat, 413 kinds of feeding-stuffs, 413 quantity of fodder, 409, 410 feeding standards for, 412 Hungarian grass, 314 composition of, 314 digestibility of, 315 Hunger, protein consumption during, 123 Hydrogen, excretion of, 103 Hyoglycocholic acid, 62 Incarnate clover, 312 Increase of live-weight in fattening, composition of, 9, 176 Indian corn, 335 Individual peculiarities, effect of, on digestion, 270 Ingredients of milk, sources of, 418 Inorganic matters of body, 20 amount of, 20 need of continual supply of, 20,462 nutrients, 47, 462 circumstances under which a lack of, may occur. 463 consumption of, by young animals, 441 how supplied, 464 importance of, 462 in fodder of milk cows, 434 supply of, in fodder, 463 Inosite, 14 Inspiration, 81 Insalivation, 55 INDEX. 513 Internal organs, muscular work of, 226 work, 226 Intestinal fluid, 64 digestion, 61 Intestines, 61 blood-vessels of, 68 contents of stomach and, 6 epithelium of, 67 length of, 61 peristaltic motion of, 61 Investigation, methods of, 104 Juice, gastric, 59 action of, on albuminoids, 59 pancreatic, 63 action of, on albuminoids, 63 carbhydrates, 63 fats, 63 ferments of, 63 Kidneys, 93 Kidney-vetch, 312 Lacteals, 68 Lactic acid, 13 Lactose, 417 Lambs, composition of gain of live-weight by, 454 fattening, 455 Stohmann's experiments, 456 Wolff's experiments, 455 feeding, 448 effect of change of fodder, 449 for maintenance, 448 feeding standard, 450 Weiske's experiments, 451 Wolff's experiments, 448 quality of fodder, 448 Laws of the formation of flesh, 120 Leaves, 322 Legumes, 301, 342 digestibility of, 343 22* 514 INDEX. Legumes, non-protein in, 313 pods of, 827 straw of, 326 composition and digestibility of, 326 uses of, 344 Legumin, 28 Leucin, 63 Lieberkiihn's glands, 64 Lignin, 39 Linseed cake, 347 digestibility of, 347 Liver, 61 glycogenic function of, 89 Live-weight, composition of gain of, by lambs, 455 increase of, in fattening, 9, 176 uncertain indications of, 115 variations of, 117 Lobules, ultimate, of lungs, "81 Lucerne, 307 digestibility of, 307 Lungs, 80 exchange of gases in, 81 ultimate lobules of, 81 Lung vesicles, 81 Lupines, 310, 343 alkaloids of, 35, 310, 343 poisonous effects of, 311 Lymph, 68 Maintenance, feeding for, 374 lambs for, 448 oxen for, 374 sheep for, 383 Maize, 385 average composition of American, 336 range of composition of American, 336 digestibility of, 337 cob, 328 fodder, 315 composition of, 315 digestibility of, 316 INDEX. Maize, fodder, ensilage of, 316 meal, exclusive feeding with, 378 sufiBLciency of exclusive feeding with, 380 Malt sprouts, 341 amides in, 342 Manifolds, 57 Manurial value of fish guano, 353 Mastication, 55 Meadow hay (see hay), 288 Meal feeding, exclusive, 58, 229, 378 Medick, 312 Mesenteric glands, 68 Metapectic acid, 46 Methods of investigation, 104 Milk, bye-products from, 355 composition of, 417 effect of fodder in maintaining flow of, 424 influence of fodder on percentage of dry matter in, 427 composition of dry matter of, 427 formation of, 416 quality of, 426 influenced by fodder, 427 individual peculiarities, 427 other conditions, 430 quantity of, 419 effect of fat on, 425 influence of fodder on, 419 period of lactation on, 419 Kiihn's experiments, 432 influence of supply of protein on, 420 Wolff's experiments, 421 sources of ingredients of. 418 substitutes for, 445 Milk cistern, 415 Milk-cows, feeding, 414 feeding standard for, 431, 432 inorganic nutrients in fodder of, 434 nutritive ratio in fodder of, 431 variations from feeding standard for, 433 Milk-fat, sources of, 174, 418 ■Milk-glands, 414 515 516 INDEX. Milk-globules, 416 Milk production, 414 with insufficient protein, 425 l\Iilk- sugar, 38, 417 source of, 418 Miller's system of exclusive meal feeding, 58, 229, 378 Millet, golden, 314 composition of, 314 digestibility of, 315 Mucedin, 30 Muriatic acid, 59 Muscles, proportion of, in body, 5 Muscular exertion, conditions of, 217 effects of, on excretion, 204 fat consumption increased by, 206 influence of, on production of fat, 199 Kellner's experiments on, 209 Noyes's experiments on, 212 Pettenkofer & Voit's experiments on, 206 products of, 218 protein consumption not increased^ by, 204, 206 theory of, 224 Voit's experiments on, 204 power, increased oxidation of source of, not necessary, 213 source of, 213 work of internal organs, 226 jiutual relations of the carbhydrates, 44 Nitrates in plants, 34 Nitrites in plants, 34 , Nitrogen all excreted in urine, 94 earlier experiments on excretion of, 94 excretion of, 94 as gas, 94 during work, 208 experiments on domestic animals, 97 Voit's experiments on, 95 influence of work on excretion of, 204 /itrogen-free extract, 51 compensation between crude fibre and, 250 composition of digestible portion of, 252 INDEX. 517 Nitrogen-free extract, composition of undigested portion of, 253 determination of, 51 digestibility of, 249 effect of carbhydrates on digestibility of, 282 Nitrogenous constituents of body, 14 composition of, 19 plants other than albuminoids, 34 Non-nitrogenous constituents of body, 7 Non-protein, 257 digestibility of, 257 influence of, on feeding standards, 371 in hay, 298 early-cut hay, 299 legumes, 313 tubers and roots, 357 Nutrients, 25, 365 changes in, during digestion, 64 classification of, 26 course of, after resorption, 71 decompositions of, in body, 87 force value of, 215 inorganic, 47, 462 nitrogenous, 26 non-nitrogenous, 38 Nutrition, animal, general laws of, 3, 5 of young animals, 436 Nutritive action of asparagin, 165 ratio, 52 effect of, on digestibility, 281 value of amides, 158 indications of, 162 gelatin, 163 Oats, 333 digestibility of, 334 Oil, addition of, to fodder in fattening, 398 Oil cake, 47, 345 composition of, 346 digestibility of, 347 uses of, 348 Oil seeds, 345 518 INDEX. Omasum, 57 Organized protein, 123, 125 Organs and parts, proportions of, in body, 5 Oxen, feeding for maintenance, 374 feeding standard, 376 Oxidations in body gradual, 93 Oxygen, distribution of, through body, 83 influence of protein on storing up of, 222 quantity taken up on production of fat, 199 quantity of, taken up by blood, 84 storing up of, 85, 220 relations to storing up of energy, 220 Oxyhaemoglobiu , 75 Palm-nut cake, 347 digestibility of, 348 effect of, on quality of milk, 429 Pancreas, 63 Pancreatic juice, 63 action of, on albuminoids, 63 carbhydrates, 63 fats, 63 ferments of, 63 Pasture grass, 288, 298 Paunch, 56 Pectic acid, 45 Pectin, 45 digestibility of, 361 Pectin substances, the, 45 Pectose, 45 Pectosic acid, 45 Pepsin, 59 Peptones, 59 in plants, 34 Pericardium, 77 Peristaltic motion, 61 Phenomena of resorption, 68 Phosphoric acid, digestibility of, 257 excretion of, by herbivora, 258 during work, 208 Pigs, feeding of, 458 INDEX. 519 Pigs, feeding of, feeding standards, 461 nutritive ratio, 459 variations in fodder, 458 Plasma, blood, 74, 75 composition of, 75 Pods of legumes, 327 Portal vein, 68, 79 Posterior aorta, 78 Potatoes, 359 composition of, 359 non-protein in, 359 Production of chemical changes, 240 fat by young animals, 440 conditions influencing, 198 determination of. 111 influenced by excessive drinking, 198 fat of body, 198 muscular exertion, 199 oxygen taken up, 199 temperature, 198 flesh, 119 by young animals, 439 determination of, 109 heat, 229 influence of evaporation of water on, 234 temperature on, 233 milk, 414 wool, influence of feeding on, 387 work, 202 Products of muscular action, 218 Protein, amount of, necessary to sustain life, 132 asparagin nearly equivalent to, 166 circulatory, 123, 125 comparative value of animal and vegetable, 351, 354 digestibility of, 254 effect of carbhyd rates on digestibility of, 280 starch on digestibility of, 281 feeding with, alone, 128, 188 carbhydrates and, 143, 191 fat and, 137, 189 formulae for digestibility of, 255 520 INDEX. Protein, glycogen from, 91, 92 heat of combustion of, 217 importance of, in fattening, 399 influence of supply of, on quantity of milk, 420 on storing up of oxygen, 223 need of, by working animals, 407 organized, 123, 125 protects fat of body, 188 food, 189 , vegetable, 26 varieties, 27 Protein consumption, 121 decreased by carbhydrates, 150 fat, 138 dependent on supply, 128, 137, 144 during hunger, 123 effect of salt on, 134 stimulants on, 136 water on, 135 factors determining, 124 in young animals, 439 not increased by work, 204, 206 Ptyalin, 55 action of, on starch, 56 Pulmonary artery, 77 circulation, 80 veins, 77 Pylorus, 61 Quality of milk, 426 Quantity of fodder, effect of, on digestibility, 459 fattening, 167 milk, 419 Radiation and conduction of heat from skin, 231 Ratio, nutritive, 59 Ration, 26 determination of nutritive effect of, 109 Rations, calculation of, 466 rules for calculation of, 473 INDEX. S21 Resorption, 66 causes of, 69 course of nutrients after, 71 phenomena of, 68 Respiration, 80 apparatus, 111 equivalents, 157 through skin, 83 Reticulum, 56 Rice, 335 Rickets, cause of, 23 Roots, 355, 361 composition of, 361 effects of, on digestibility of coarse fodder, 283 feeding value of, 362 general properties of, 355 variations in composition of, 362 Root crops, tops of, composition of, 321 digestibility of, 321 Rowen, 288, 298 Ruminants, stomach of, 56 Rumination, 56 may be suspended, 58 Rye, 333 Sainfoin, 313 Saliva, 55 action of, on food, 56 Salivary glands, 55 Salt, common, effects of, on digestibility, 287 protein consumption, 134 uses of, 23 Salt-hunger, 21 effects of, 21 Salts, essential and accidental, 22 Sarkolactic acid, 13 Saving of work by concentrated fodder, 228 Seradella, 313 Shearing, effect of, on fattening, 403 Sheep, fattening, 399 best age for, 402 522 INDEX. Sheep, fattening, effect of shearing on, 403 feeding standards, 400 proportion of protein for, 399 quantity of water, 403 maintenance feeding of, 383 feeding standards, 387 Weende experiments, 383 need relatively more food than cattle, 383 Skin, conduction and radiation of heat from, 231 respiration through, 83 Soda, salts of, in bile, Q2 Solid excrements, composition of, 73 tissues, proportions of, 5 Sour hay, 317, 318 Source of muscular power, 213 Sources of fat, 169 Stable, temperature of, 237 Stage of growth, effect of, on digestibility of hay, 263 quality of hay, 292, 302 Starch, 41 composition of, 43 effect of, on digestibility, 280 properties, 41 Starch-cellulose, 42 grains, 42 Stimulants, effect of, on chemical processes in body, 136, 242 Stomach of ruminants, 56 Storing, effect of, on digestibility, 262 Storing up of energy in body, 219 influence of protein on, 222 oxygen, 85 relation of, to storing up of energy, 220 Stover, 315 composition of, 315 Straw a valuable fodder, 322 digestibility of, 324 of the cereals, 322 legumes, 326 composition and digestibility of, 326 manner of using, 325 variations in composition of, 323 INDEX. 523 Structure of milk-glands, 414 Sugar, effect of, on digestibility of coarse fodder, 383 in blood, 13 beet pulp, 363 Sugars, the, 43 composition of, 43 Sulphuric acid, excretion of, during work, 308 Swine, fattening, 404 choice of fodder, 405 feeding standards, 404 mineral matters, 405 quantity of fodder, 404 Systemic circulation, 80 Taurocholic acid, 63 Temperature, influence of, on fat-production, 198 production of heat, 333 of stable, 237 Theory of muscular exertion, 224 Thoracic duct, 68 Time occupied in digestion, 105 Time of cutting, effect of, on digestibility, 363 Tissues, solid, proportions of, 5 Tops of root crops, composition of, 321 digestibility of, 321 Trypsin, 63 action of, on albuminoids, 63 Tubers, 355, 359 general properties of, 355 proportion of non-protein in, 357 Tyrosin from albuminoids, 63 Udder, 415 Ultimate lobules of lungs, 81 Urea, 84, 93 from albuminoids, 87 Uric acid, 93 Urine, 93 nitrogen all excreted in the, 94-101 Use of distillers' grains, 340 524 INDEX. Uses of common salt, 23 oil cake, 348 Value of straw, 332 Variations in composition of straw, 323 of live-weight, 117 Varieties of animal albuminoids, 15 Vegetable albumin, 27 casein, 28 composition of, 28 fats, 46 fibrin, 29 protein, 26 Vein, hepatic, 68, 79 left subclavian, 68 portal, 68, 79 Veins, 79 pulmonary, 77 Vena cava, anterior, 77 posterior, 77 Ventricles of the heart, 77 Vesicles of lungs, 81 Vetches, 309 Villi, 67 Vital heat, 230 how regulated, 230 Voit's experiments on excretion of nitrogen, 95 muscular exertion, 204 Warming ingesta, expenditure of heat in, 236 Water, efifect of work on excretion of, 207 excretion of, 102 influence of, on protein consumption, 135 proportion of in body, 7 Weaning, 446 Wheat, 832 gluten, 28 Whey, 354 Wool production, 387 influence of feeding on, 387 Work, classification of, 202 INDEX. . 525 Work, efiFect of, on digestion, 271 excretion, 204 of carbonic acid, 206 nitrogen, 204 water, 207 fat consumption, 207 excretion of gaseous nitrogen during, 208 internal, 226 Kellner's experiments on, 209 Noyes's experiments on, 212 Pettenkofer & Voit's experiments on, 206 production of, 202 protein consumption not increased by, 204, 206 saving of, by concentrated fodder, 228 Voit's experiments on, 204 Working animals, feeding, 407 importance of fat to, 408 need of protein for, 407 oxen, feeding of, 408 standard, 408 STOUNO animals, amount of food consumed by, 437 consumption of inorganic nutrients by, 441 excretion of carbonic acid by, 440 general laws of nutrition of, 436 production of fat by, 440 flesh by, 439 protoin consumption in, 439 BmPERTY UBMAh N. 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