UNIVERSITY OF ILLINOIS Agricultural Experiment Station BULLETIN No. 317 RELATIVE ENERGY VALUE OF ALFALFA, CLOVER, AND TIMOTHY HAY FOR THE MAINTENANCE OF SHEEP By H. H. MITCHELL, W. G. KAMMLADE, and T. S. HAMILTON URBANA, ILLINOIS, DECEMBER, 1928 CONTENTS Page FIRST EXPERIMENT: ALFALFA, CLOVER, AND TIMOTHY HAY. . 131 Outline of Experiment 131 The Experimental Data 132 Body Weights 132 Digestibility and Energy Content of Rations 134 Feed and Metabolizable Energy Requirements for Maintenance 139 Summary of the First Experiment 140 Critical Consideration 141 SECOND EXPERIMENT: ALFALFA AND TIMOTHY HAY 144 Outline of Experiment 144 Results of the Second Experiment 146 Chemical Composition of the Check Sheep 146 Feeding Period and Changes in Body Weight 150 Amount and Composition of Wool Sheared at End of Period 1 151 Digestibility and Metabolizable Energy Content of Rations 151 Nitrogen Balances 154 Chemical Composition of Surviving Sheep 154 Growth of Wool by Sheep on a Submaintenance Ration 156 Comparison of Composition of Tissues From Well-Fed and From Emaciated Sheep 157 Loss of Body Constituents During Feeding Period 158 Feed Consumption and Its Content of Metabolizable Energy 159 Summary of the Se-cond Experiment 163 Conclusions of the Second Experiment 167 RELATIVE ENERGY VALUE OF ALFALFA, CLOVER, AND TIMOTHY HAY FOR THE MAINTENANCE OF SHEEP By H. H. MITCHELL, W. G. KAMMLADE and T. S. HAMILTON' The method in most common use of measuring the value of dif- ferent feeds as sources of nutritive energy for farm animals involves the employment of average values of the total digestible nutrients. It seems clear, however, that the determination of the digestible or- ganic matter of a feed, even when allowance is made for the differ- ences in metabolizable energy among the individual nutrients, can give no certain information as to the utilization of the digestible ma- terial in metabolism. There are two important objections to the use of values for the total digestible nutrients of feeds as measures of their content of nutritive energy, i.e., food energy available for expenditure in main- tenance or work, or for storage in the tissues or secretion in the milk. The first objection relates to the fact that the calculation of such values is based on the assumption that the difference between the amounts of nutrients consumed and the amounts of nutrients appear- ing in the feces represents those fractions which are available to the animal for maintenance and production. In the case of nonrumi- nants this assumption may be roughly true, but in the case of rumi- nants, in which extensive fermentations are occurring in the fore part of the alimentary tract, considerable amounts of gaseous material un- available to the animal are formed and considerable amounts of heat representing losses in nutritive energy are being produced. These losses of matter and energy cannot be determined from an analysis of the feces, and yet they represent losses of nutritive energy as real as the energy of the undigested organic constituents of the feces. This objection has been developed and illustrated by Fries. 2 The second important objection to the use of the total digestible nutrients of feeds as measures of nutritive energy relates to the fact that large losses of energy occur in animals during the digestion and assimilation of feed, these losses being represented by increases in the heat production of the animal. Regardless of the causes for such losses of energy, they are inevitable and therefore must relate to defi- nite physiological processes occurring in the animal body consequent J H. H. MITCHELL, Chief in Animal Nutrition; W. G. KAMMLADE, Assistant Chief in Sheep Husbandry; and T. S. HAMILTON, Associate in Animal Nutrition. With the technical assistance of C. H. KICK. 2 Fries, J. A. Digestibility of cattle feed. Amer. Soc. Anim. Prod. Proc., 1922, 33. 127 128 BULLETIN No. 317 [December, upon the digestion of feed, its absorption into the blood and its trans- position to the tissues. This increment in heat production is not avail- able for maintenance except under conditions in which the environ- mental temperature is lower than the critical temperature of the fast- ing animal. The net energy values of Armsby are complete expressions of the actual values of feeds as sources of nutritive energy, since they are obtained by deducting from the gross energy of the feed not only the gross energy of the feces, but also the energy losses due to gastro- intestinal fermentations, to incomplete oxidations in the body, and to the stimulating effect of feed on heat production. They represent, therefore, the ultimate net return to the animal in nutritive energy resulting from the consumption of the feed. Altho net energy values represent a complete scheme of evaluat- ing feeds with reference only to their content of nutritive energy, the total digestible nutrients of different feeds may still represent their relative energy values provided that the losses of energy not con- sidered in digestion experiments were roughly proportional to the content of total digestible nutrients; in other words, that the net en- ergy value per pound of digestible nutrients was practically the same for different feeds. However, the calculations contained in Table 1, TABLE 1. ESTIMATED NET ENERGY PER POUND OF DIGESTIBLE NUTRIENTS FOR A FEW REPRESENTATIVE FARM FEEDS Feed Net energy per 100 pounds 1 Digestible nutrients per 100 pounds 2 Net energy per pound digestible nutrients therms 43.02 Ibs. 48.5 therms .887 Alfalfa hay 34.23 51.6 .663 38 68 50 9 .760 34.81 45.6 .763 15.90 17.7 .898 Corn 85.50 85.7 .998 Oats 67 56 70.4 .960 Wheat 91.82 80.1 1.146 Wheat bran 53.00 60.9 .870 Cottonseed meal, prime 90.00 75.5 1.192 Linseed oil meal, old process 88.91 77.9 1.141 J From Armsby's "Nutrition of Farm Animals," 1917. 2 From Henry and Morrison's "Feeds and Feeding," 18th ed., 1923. of a few commonly used roughages and concentrates, indicate that the net energy value per pound of digestible nutrients varies considerably for different feeds and in general is lower for roughages than for con- centrates. Attention is called particularly to the content of alfalfa, clover, and timothy hay in total digestible nutrients and in net energy. Ac- cording to their content of digestible nutrients these three hays are very nearly equal as sources of nutritive energy. Taking alfalfa hay as 100 in its content of total digestible nutrients, clover hay has a 1928] ALFALFA, CLOVER, AND TIMOTHY HAY FOR SHEEP 129 value of 99 and timothy hay a value of 94. However, according to the net energy calculations of Armsby, based upon the same average an- alyses of the hays as were used in computing their content of total digestible nutrients, considerable differences in their content of nutri- tive energy exist among them. Taking the net energy content of al- falfa hay as 100, clover hay has a value of 113 and timothy hay a value of 126. The net energy values of these hays have been recom- puted by Forbes and Kriss. 1 If the revised net energy value per kilo- gram of dry matter of alfalfa hay be taken as 100, the revised value for clover hay becomes 106 and that for timothy hay 133. The relatively high net energy value of timothy hay is particu- larly noteworthy, since it apparently contradicts the current belief of the superiority of alfalfa over timothy hay. The contradiction is, however, only apparent, since the established superiority of alfalfa over timothy hay is founded upon a basis other than its content of nutritive energy. Its greater palatability for most classes of live- stock also contributes to its economic superiority over timothy hay. The individual experiments of Armsby and associates relative to the utilization of the energy of these three hays are summarized in Tables 2, 3, and 4. In these calculations the original figures of Arras- TABLE 2. SUMMARY OF DETERMINATIONS OF UTILIZATION OF ENERGY OF ALFALFA HAY BY STEERS, REPORTED BY ARMSBY AND ASSOCIATES (Energy per kilogram of dry matter) Exp. No. Steer No. Gross Metabolizable Net available Literature reference 208... C D E F H H J cals. 4 405 4 407 4 408 4 338 4 368 4 374 4 334 4 376 calf. 1 820 1 729 1 837 1 810 2 056 2 012 1 945 1 887 pet. of gross 41.3 39.2 41.7 41.8 47.1 46.0 44.9 43.1 cals. 684 392 635 671 1 017 895 927 746 pet. of metab. 37.6 22.7 34.6 37.1 411 . 5 44.5 47.7 39.1 J. Agr. Res. 3, 435. 1915. Ibid. 18. 269. 1918. 208 208 209 . . 212 212 216 . Average.. . . TABLE 3. UTILIZATION OF ENERGY OF RED CLOVER HAY BY STEERS SUMMARY OF EXPERIMENTS BY ARMSBY AND ASSOCIATES (Energy per kilogram of dry matter) Exp. No. Steer Xo. Gross Metabolizable Net available Literature reference 179... I I I K cals. 4 438 4 486 4 '367 4 430 cals. 1 926 2 076 2 127 1 954 2 021 pet. of gross 43.4 46.3 44 '.7 44.8 cals. 934 1 651 1 771 1 Oil 973 1 pet. of metab. 48.5 79.5 83.3 51.7 50. 1 1 J. Agr. Res. 3, 435. 1915. Ibid. 7, 379. 1916. 186a 186b 220 Average.. . . 'Not including the results in Experiment 186. 'Forbes, E. B., and Kriss, M. Revised net energy values of feeding stuffs for cattle. Jour. Agr. Res. 31. 1083. 1925. 130 BULLETIN No. 317 [December, TABLE 4. UTILIZATION OF ENERGY OF TIMOTHY HAY BY STEERS, SUMMARY OF EXPERIMENTS BY ARMSBY AND ASSOCIATES (Energy per kilogram of dry matter) Exp. No. Steer No. Gross Metabolizable Net available Literature reference 190... A A A B B B I cats. 4 495 4 509 4 515 4 493 4 509 4 515 4 483 4 503 cals. 1 785 1 835 2 086 1 844 1 895 2 036 1 953 1 919 pet. of gross 39.7 40.7 46.2 41.0 42.0 45.1 43.6 42.6 cals. 1 067 1 306 1 184 922 1 102 1 082 1 294 1 137 pet. of metab. 59.8 71.2 56.8 50.0 58.2 53.1 66.3 ' 61.5 J. Agr. Res. 3, 435. 1915. 200 207 190 200 207 ... 174 Average. . by for the heat production of the steers were used rather than the recalculations of Forbes and Kriss. Per kilogram of dry matter, the three hays are closely similar in their content of gross and metabolizable energy. The slight differ- ences between the average figures are probably not significant. How- ever, distinct differences appear with reference to their net energy content per kilogram of dry matter, particularly if the results of Ex- periment 186 on red-clover hay are omitted. Armsby himself was in- clined to disregard this experiment in the computations of his average results on the basis of certain unsatisfactory experimental conditions, while Forbes and Kriss (loc. cit.) have definitely discarded it in their recomputations of Armsby's work. The close agreement between the much lower results of Experiments 179 and 220 may be taken as pro- visional justification for disregarding the results of Experiment 186, tho evidently the situation with respect to the net energy value of red- clover hay is in a very unsatisfactory condition. These experiments indicate clearly that the metabolizable energy of timothy hay is distinctly better utilized by steers in covering their maintenance requirement for energy than is the metabolizable energy of alfalfa hay. The two concordant results on red-clover hay would indicate that it occupies an intermediate position in this respect. The average percentage utilization of the metabolizable energy of timothy hay is 61.5, of red-clover hay 50.1, and of alfalfa hay 39. 1. 1 Forbes and Kriss, in their recomputations and reinterpretations of Armsby's work, arrive at different averages, i.e., 60.8 for timothy, 49.6 for clover, and 47.1 for alfalfa, bearing the same relation to one another, how- ever. values apply only from an approximate maintenance level of feeding to one permitting moderate fattening. Forbes and associates have shown that at lower levels of feeding, the metabolizable energy of feeds is utilized to a greater extent (Forbes, E. B., Fries, J. A., Braman, W. W., and Kriss, M. The rela- tive utilization of feed energy for maintenance, body increase and milk produc- tion in cattle. Jour. Agr. Res. 33, 483. 1926.) ALFALFA, CLOVER, AND TIMOTHY HAY FOK SHEKP 131 The considerable difference in the results obtained between the two most common methods of measuring the content of farm feeds in nutritive energy relative to the values for these three common hays, is sufficient justification for a redetermination of the value of these feeds as sources of energy in maintenance, preferably by some method different from that heretofore used. Altho the net energy values possess a sounder scientific basis than the contents of total digestible nutrients, it is always well to check up such laboratory results by observations obtained from feeding experiments of longer duration. It was the purpose of the experiments to be reported below to make such de- terminations and observations. FIRST EXPERIMENT: ALFALFA, CLOVER, AND TIMOTHY HAY Outline of Experiment Fifteen western ewes, three to four years of age and weighing approximately 100 pounds each, were divided into three equal lots, the first to receive alfalfa hay, the second clover hay, and the third timothy hay. Since it was questionable whether timothy hay, in the amounts required for maintenance of body weight, would contain enough protein to cover the protein requirement, each sheep in the three lots was given approximately .15 pound of linseed oil meal per 100 pounds initial live weight daily. A possible deficiency of timothy hay in minerals was removed by allowing the timothy-hay sheep ac- cess to a mineral mixture consisting of equal parts of special steamed bone meal, finely ground limestone, and salt. In each lot the con- sumption of hay was regulated so as just to maintain the body weight of the sheep. Under these conditions the relative amounts of the dif- ferent hays required for maintenance per 100 pounds live weight repre- sent their relative values as sources of nutritive energy. All sheep were individually fed and at all times had access to salt. Except during feeding, each lot of sheep was allowed the run of a pen ap- proximately 1 by 5 rods in dimensions. Samples of feed were taken daily at the barns at the same time that the daily rations were weighed out, and these daily samples were composited for the entire experiment and submitted to routine chemical analysis. The analyses of these feed samples will be found in Table 5. At the end of its maintenance period digestion and metabo- lism studies were made on each of the sheep in the three lots for the purpose of determining the content of the maintenance rations in di- gestible nutrients and in metabolizable energy. The feed, feces, and 132 BULLETIN No. 317 [December, TABLE 5. PERCENTAGE COMPOSITION OF FEEDS FED AT BARN Feed sample Dry sub- stance Crude protein (Nx 6.25) N-free extract Crude fiber Ether extract Ash Gross energy per gram Clover hay perct. 94.73 perct. 10.19 perct. 43.32 perct. 31.70 perct. 2.32 perct. 7.20 sm. cals. 4 154 Alfalfa hay 93.56 16.38 43.52 22.85 2.82 7.99 4 195 Timothy hav 96. 15 7.44 51.19 27.73 4.09 5.70 4 317 Linseed oil meal 92.80 36.19 36.51 7.65 6.53 5.92 4 402 urine were submitted to a direct determination of gross energy by means of the bomb calorimeter. These determinations afforded the opportunity of computing the amounts of digestible nutrients and of metabolizable energy required for maintenance for each experimental ration. The Experimental Data Body Weights. The experimental feeding started July 9, 1924, and within the following two weeks the body weights of the alfalfa and clover-hay sheep were adjusted to the amounts of hay calculated to be sufficient for maintenance. The timothy-hay sheep were much slower in reaching a constant level. In this experiment it was considered, somewhat arbitrarily, that a good determination of the maintenance requirement would result in a period of 8 weeks during which the body weight remained approxi- mately constant on constant feed. Most of the maintenance experi- ments on the alfalfa and clover-hay groups were, however, of 13 to 15 weeks' duration. The weekly weights of individual sheep are given in Table 6. One sheep in the alfalfa-hay group died in the early part of September from unknown causes and the data on this animal may not be of any considerable significance. It will be seen, however, that all of the alfalfa and clover-hay sheep maintained their weight at an approxi- mately constant level from July 23 to the time when experimental feeding stopped. While the variation in weight from week to week was at times considerable, there is no apparent tendency for the weights of these sheep either to increase or to decrease progressively. The maintenance trials on the timothy-hay sheep were not so satisfactory, since a constant level in weight cannot be considered to have been established until September 10. The experiment with these sheep may also be questioned on two other grounds. First, at the end of the experiment the condition of the sheep was' noticeably poorer than that of the sheep in the alfalfa- and clover-hay groups, indicating that in part of the feeding period at least they had been compelled to draw upon their body stores of fat to provide sufficient energy for maintenance. This withdrawal of body stores very probably occurred in the interval from the beginning of the experiment to September 10, 1988} ALFALFA, CLOVER, AND TIMOTHY HAY FOR SHEEP 133 5 U Q 5> 5 81 O O PQ X CO I 1 rH Si Si O o o ss o. o Si Si O Ci Si 00 '^2 S^ r/: 2?'^' IO OI a ^! o o : : : : M : : : M ^^ rtCC > rH^MQJ ntenancc eight. . . Illl*" g-goo" 5 Sou" 3 aiccOO OOO 1 134 BULLETIN No. 317 [December, during which all decreased slightly in weight. Second, thru a mis- understanding at the barns small amounts of feed refused from the amounts offered after October 1 were not weighed or saved for an- alysis. This refused feed, however, is known to be inconsiderable in amount and probably is of no great significance in interpreting the results of the experiment. The effect of this oversight would be to in- troduce an error in the opposite direction from that consequent upon a possible withdrawal of fat from the bodies of the sheep during the maintenance trial. Digestibility and Energy Content of Rations. The digestion and metabolism periods were of 10 days' duration. Tests were run upon each of the 15 sheep in the experiment; the results obtained with 4 of the sheep had to be discarded, because in these cases the allowance of linseed oil meal was inadvertently increased above the allowance that they had been receiving. Before the mistake was discovered these sheep had been taken off experiment and otherwise disposed of, so a repetition of their trials was impossible. However, three good di- gestion and metabolism studies remain on the alfalfa ration, four on the clover-hay ration, and four on the timothy-hay ration. No orts were left in any of these trials and they were in every respect satis- factory. A summary of the coefficients of digestibility is contained in Table'?. TABLE 7. COEFFICIENTS OF DIGESTIBILITY OF RATIONS Sheep No. Dry substance Crude protein X-free extract Crude fiber Ether extract Alfalfa-hay ration 156 perct. 67 66 04 ^ 65.7 perct. 77 75 74 75.3 fierct. 79 78 7s 78.3 perct. 44 46 41 43.7 perct. 63 54 59 5S.7 157 158 Average Clover-hay ration 160 61 56 60 56 58.3 60 58 63 50 57.8 76 7S 74 77 76.3 44 23 41 30 34.5 80 76 81 80 79.3 161 162 163 Average Timothy-hay ration 165... 61 60 58 63 60.5 61 61 61 57 60.0 69 71 (IS 75 70.8 53 42 46 47 47.0 68 58 54 60 60.0 166 167 168 Average The individual coefficients for the different rations agreed fairly well among themselves with few exceptions. For Table 8 the digesti- bility of the hays alone has been computed, assuming an average di- gestibility for the linseed oil meal as given in Henry and Morrison's "Feeds and Feeding." Because of the small proportion of linseed oil 1928} ALFALFA, CLOVER. AND TIMOTHY HAY FOR SHEEP TABLE 8. COMPUTED COEFFICIENTS OF DIGESTIBILITY FOR HAYS ALONE 135 Sheep No. Dry substance Crude protein N-frer extract Crude fiber r extract Alfalfa-hay ration 156 .. perct. 66 65 62 64.3 perct. 75 73 71 73.0 perct. 79 78 77 78.0 44 45 40 43.0 perct. .-,7 18 51.7 157 158 Average Clover-hay ration 160... 59 53 58 55 56.3 52 50 57 41 50.0 75 7.s 72 77 75.5 44 21 40 29 33.5 78 71 7S 81 7'i - 5 161 162 163 Average Timothy-hay ration 165... 59 57 55 61 58.0 45 43 43 38 42.3 68 71 67 7:. 70.3 53 42 45 47 46.8 67 52 48 57 56.0 166 167 . . 168 Average meal in the rations, the coefficients in Table 8 are quite similar to those in Table 7 with the exception of the coefficients of digestibility of protein for timothy hay, these coefficients being markedly lower than the similar coefficients for the combined ration of timothy hay and linseed oil meal. From the average coefficients of digestibility for the three differ- ent rations and their average chemical composition, the average con- tent of the experimental rations in total and digestible nutrients was computed, the results being given in Table 9. The alfalfa-hay and timothy-hay rations were very similar in their content of total digest- ible nutrients, the clover-hay ration being somewhat lower in this re- spect. The content of total and digestible protein decreased from the alfalfa hay thru the clover-hay to the timothy-hay ration. TABLE 9. AVERAGE PERCENTAGE COMPOSITION OF THE THREE EXPERIMENTAL RATIONS Dry sub- stance Crude protein N-free extract Crude fiber Fat Ash Total di- gestible nutrients Alfalfa-hay, oil-meal ration Total 93.50 61.43 18.01 13.56 42.94 33.62 21.60 9.44 3.13 1.84 7.82 66!76 Digestible Clover-hay, oil-meal ration Total 94 56 12.52 7.24 42.71 32.59 29 . 54 10.19 2.70 2.14 7.08 I - Digestible 55.13 Timothy-hay, oil-meal ration Total 94.47 57. 15 10.21 6.12 49.01 34.70 25.34 11.91 5.70 3.42 5.65 66!42 Digestible 136 BULLETIN No. 317 [December, In the digestion trials the urine was collected and analyzed for nitrogen, permitting a determination of the nitrogen balances. From Table 10 it is evident that all the sheep were in positive nitrogen bal- ance. In general the positive balance with the timothy-hay sheep was less than the balances for the sheep on the other rations. However, the TABLE 10. NITROGEN BALANCES OF SHEEP IN MAINTENANCE PERIODS Sheep No. Nitrogen of feed consumed Nitrogen of feces Nitrogen of urine Total nitrogen excreted Nitrogen balance Alfalfa, oil-meal ration 156 grams 26.7 26.7 29.6 grams 6.1 6.6 7.7 grams 18.5 18.0 20.8 grams 24.6 24.6 28.5 gramt +2.1 +2.1 +2.1 157 158 Clover, oil-meal ration 160. .. 21.3 20.8 17.0 20.0 8.5 8.6 6.2 9.9 10.7 10.0 8.2 10.0 19.2 18.6 14.4 19.9 +2.1 +2.2 +2.6 + .1 161 162 163 Timothy, oil-meal ration 165 ... 11.0 12.0 11.5 10.7 4.3 4.6 4.5 4.6 4.9 4.0 5.4 4.8 9.2 8.6 9.9 9.4 + 1.8 +3.4 + 1.6 + 1.3 166 167 168 storage of nitrogen on the clover-hay ration was evidently as extensive as the storage of nitrogen on the alfalfa-hay ration containing almost twice as much digestible crude protein. The computations of the metabolizable energy of the different rations will be found in Table 11. The gross energy content of feed, feces, and urine was determined directly by the bomb calorimeter. From the daily intake of digestible carbohydrates the methane pro- duction was estimated by means of Armsby's average factor and the energy content of the methane produced was then computed, taking 1 gram of methane equal to 13.34 calories; a small correction of the energy of the urine was made to allow for the storage of protein. 1 The total metabolizable energy of the combined rations was computed per kilogram of dry matter and per pound of digestible organic matter. The average metabolizable energy per kilogram of dry matter was 2.292 therms for the alfalfa-hay ration, 1.944 therms for the clover- hay ration and 2.177 therms for the timothy-hay ration; per pound of digestible organic matter the values were respectively, 1.729, 1.589, and 1.668 therms. On the basis either of total dry matter or digestible organic matter the alfalfa ration was found to contain the greatest amount of metabolizable energy, the timothy-hay ration ranking next and the clover-hay ration least. The average percentage of the gross 'Armsby, H. P., and Fries, J. A. U. S. Dept. Agr. Bur. Anim. Indus. Bui. 101, 31. 1908. ALFALFA, CLOVER, AND TIMOTHY HAY FOR SHEEP 137 "c 1 0-1 | | o j^-5 c 3 d s o ^"3 u c " u M S g OS 0^*1*3 -~- cons o jlljll E- < tf 3 a S SJS *> S K S o 5"5 fe f_ C N - c- - X r -1 W H c 5 cl fe-5 H S o^-a H O W-g W ^ 2 H K c C Wo g O pg II a c"" Wo &H O fc o nl H cin i .- r - /: O iC 33 * O C '-" ~. '^ X S- i -r 3; tc r^ cc to B i 2 I ?7 >! M ft " --T '^ ~ V M M rj M C Si ' :O -f t-CC X X - C X O t^ C-. c; >^ ic t~ ^ to ^ X i r~ ^H ^H < C^ ^H M "o S S C^ D ?) M Cq rHlM rt l-l M ?) C^ C-l ^ C _o *a W XL'S C re c^ c-j si Ci -i M O O i eg IN CO >.- >r. L- ..o t>. -H t^ O ?0 T}1 Tj( T)< fl -< to t- c t^ o >; t~ K C-. 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CO M CO 1 CO C-) O3 Tf OS X IO CO O IN m O X CD 00(NO3O1MO co <-> o! <-i "~ x I CNO X -* O x 10 c> x m CD OOCSOO5O5OS : : : : : a :::::! '. a! , . v > Tf IO CO t 00 ^ O iO *O 10 iO , . ~ > O> O -^ ^ CC < -f >O CO I s - 00 ^ O * sO CO SO 1928} ALFALFA, CLOVER, AND TIMOTHY HAY FOR SHEEP 139 energy that proved to be metabolizable was 51.5 for the alfalfa-hay ration, 43.9 for the clover-hay ration, and 48.0 for the timothy-hay ration. Feed and Metabolizable Energy Requirements for Maintenance. The final computations of the experiment arc given in Table 12. The maintenance weight of the individual sheep in the alfalfa-hay and clover-hay groups is simply the average of all weekly weights in Table 6, except for Sheep 155. In this case the last weight, taken two days before the death of the animal, is not included in the average. For the timothy-hay sheep the maintenance weight is taken as the average of the last eight weights in Table 6. During this period the weights of the sheep were maintained at a practically constant level. The aver- age daily feed records given in Table 12 refer to the periods covered by the average maintenance weights. The metabolizable energy con- sumed daily was obtained by the use of the individual results of the metabolism trials in the case of those sheep upon which satisfactory trials were obtained; in the case of Sheep 154, 155, 159, and 164 the average results for their respective groups were used in computing their average daily intake of metabolizable energy. In the last four columns of Table 12 the average daily intake of feed (in pounds) and of metabolizable energy (in calories) has been computed to 100 pounds body weight, using both the direct-weight ratio and the sur- face ratio, i.e., the ratio of the weights to the two-thirds power. A comparison of the results obtained by the weight ratio with those ob- tained by the surface ratio shows that the latter method of compu- tation gives individual results within the three groups agreeing much better among themselves. They will therefore form the basis of the following discussion. The average weight of feed required per day per 100 pounds body weight was 1.917 pounds for the alfalfa-hay group, 1.824 pounds for the clover-hay group, and 1.593 pounds for the timothy-hay group. In view of the individual variations within the different groups of sheep the average difference between the alfalfa-hay ration and the clover- hay ration cannot be considered highly significant. The average dif- ference between the timothy-hay group and either of the other two groups would seem to be highly significant, since none of the indi- vidual results on the alfalfa-hay ration or the clover-hay ration was as low as the highest result with the timothy-hay ration. It seems fair to conclude, therefore, from these results that the timothy-hay ration was distinctly higher in net energy than either of the other rations. The results also suggest that the clover-hay ration was higher in net energy than the alfalfa-hay ration. Since the proportion of linseed oil meal in the three experimental rations was approximate- ly the same, it also seems fair to conclude that the timothy hay used in this experiment had a higher net energy value than either the alfal- 140 BULLETIN No. 317 [December, fa hay or the clover hay, and that the clover hay probably was higher in net energy than the alfalfa hay. Considering the metabolizable energy required per 100 pounds live weight in the three groups, the average value for the alfalfa hay ration (1,864 calories) was distinctly higher than that for either the clover- hay ration (1,521 calories) or the timothy-hay ration (1,507 calories). Comparing the individual values of the alfalfa-hay group with the individual values of the clover-hay group, only one result in the former group is lower than the highest result in the latter group. All of the individual results of the alfalfa-hay sheep were higher than the indi- vidual results of the timothy-hay sheep. On the other hand, the av- erage metabolizable energy required per day per 100 pounds live weight by the clover-hay sheep was practically the same as that re- quired by the timothy-hay sheep, the individual variations within these two groups rendering the small average difference entirely insig- nificant. It appears, therefore, that for maintenance the metabolizable energy of clover liny is approximately of equal value with that of timothy hay. If it may be assumed that the net energy required for maintenance per 100 pounds live weight was the same in all groups, it may be concluded that the percentage availability of metabolizable energy was approximately the same for clover hay as for timothy hay, but was distinctly lower for alfalfa hay. Summary of the First Experiment The purpose of the experiment reported above was to determine the relative energy value of alfalfa hay, clover hay, and timothy hay for the maintenance of sheep. Three groups of mature sheep (ewes) containing five animals in each were fed individually approximately .15 pound linseed oil meal daily per 100 pounds initial live weight and enough of the three hays under investigation to maintain body weight. A determination of the digestibility and the content of metabolizable energy of the three rations was made on three of the alfalfa-hay sheep and four each of the clover and timothy-hay sheep. The alfalfa-hay ration and the timothy-hay ration contained ap- proximately the same percentage content of total digestible nutrients, i.e., 60.76 and 60.42 respectively, while the clover-hay ration was slightly lower with a percentage of 54.84. Since the proportion of lin- seed oil meal was approximately the same in all three rations, the con- tents of total digestible nutrients in the three hays were probably in the same proportion as in the rations. The average metabolizable energy per kilogram of dry matter was 2.292 therms for the alfalfa-hay ration, 1.944 therms for the clover- hay ration, and 2.177 therms for the timothy-hay ration. The alfalfa hay used in this experiment was apparently higher in metabolizable energy than the timothy hay, which in turn was apparently higher than clover hay. 19-28} ALFALFA, CLOVER. AND TIMOTHY HAY FOR SHEEP 141 The average amounts of feed required per day per 100 pounds live weight were 1.917 pounds for the alfalfa-hay ration. 1.824 pounds for the clover-hay ration, and 1.593 pounds for the timothy ration. A comparison of the individual results in the three groups indicates that distinctly smaller amounts of the timothy-hay ration were require'! maintenance than of the alfalfa or clover-hay ration. The average difference between the alfalfa-hay and the clover-hay ration- suggi - a superiority of the latter, but in view of the individual variations within the two groups, no positive conclusion is justified. The average amounts of metabolizable energy per day per 100 pounds live weight required for maintenance were 1.86-4 caloric- the alfalfa-hay ration, 1.521 calories for the clover-hay ration and 1,507 calories for the timothy-hay ration. A study of the individual data indicates that there is no significant difference between the clover and timothy groups in this respect. However, distinctly more metab- olizable energy was required in the alfalfa ration than in either of the other two. In view of the similar proportions of linseed oil meal used in the three experimental rations it may be concluded that timothy hay has a distinctly higher net energy value than either alfalfa hay or clover hay. The results also -uggest that clover hay has a slightly higher net energy value than alfalfa hay. It may also be concluded on the assumption that the basal metab- olism per unit of body surface was the same in all groups that the net availability of the metabolizable energy of the alfalfa hay was dis- tinctly lower than that of the clover hay or of the timothy hay. Xo difference between the latter two hays in this respect was noted. Critical Consideration In the preceding experiment no attempt was made with the sheep getting the alfalfa or clover rations to maintain them at exactly their initial weights, and as a result certain adjustments in weight occurred to the amounts of feed fed. With the sheep on the timothy-hay ration, an initial loss in weight was general and in most cases considerable, but these losses occurred in spite of all that could be done to avert them. They were due simply to the refusal of the sheep to consume enough of the ration offered. While there is no good reason to sup- pose that the slight adjustments of body weight to feed that occurred in the alfalfa and clover lots exerted any influence upon the energy requirements of the sheep, the objection may be raised against the timothy results that the considerable losses in weight incurred by the sheep in the first few weeks of feeding may have depressed their basal metabolism and possibly their activity, so that their energy require- ments per unit of weight or of surface were appreciably less than those of the alfalfa-hay and clover-hay sheep. In such a case the smaller 142 BULLETIN No. 317 [December, quantities of metabolizable energy in timothy hay required for main- tenance of weight would not necessarily indicate a greater percentage availability, but may have been the result entirely of a lowered re- quirement of net energy by these sheep. That marked undernutrition may lower the basal metabolism has been shown conclusively by Benedict, Miles, Roth, and Smith 1 for men and less certainly by Benedict and Ritzman 2 for steers; a general re- view of the subject has been written by Lusk. 3 It appears that under the conditions of a greatly restricted supply of food, the body ad- justs itself to a more economical level of expenditure as a measure of self-preservation. Such experiments do not prove that small restric- tions of diet, occasioning small losses in body weight, will exert such an effect upon metabolism. They also throw no light upon the relation of the fat stores in the body to the response to a restricted diet, al- tho it appears reasonable to suppose that a fat animal would respond less quickly than a lean animal since its stored food could, for a time, supplement its short rations. It seems dangerous, therefore to generalize too widely from the limited data available, and in particular to assume that basal metab- olism is readily altered by the plane of nutrition. If this were true, basal metabolism determinations would not show the remarkable con- stancy that has been repeatedly noted in human experimentation when allowance is made for differences in size, sex, and age, and standards of basal metabolism would be of little significance, contrary to general experience. Gulick 4 has found in his own case that overmitrition, in- ducing a 20-percent increase in body weight, had no effect on his basal metabolic rate. Overmitrition leading to extreme obesity (as much as 160 percent overweight) has been very conclusively shown by Means 5 to be associated with normal basal metabolic rates per square meter of body surface, a finding that has been confirmed by Strouse, Wang, and Dye 6 and others. The latter investigators have been un- able to show that underweight is consistently associated with lowered 'Benedict, F. G., Miles, W. R., Roth, P., and Smith, H. M. Human vitality and efficiency under prolonged restricted diet. Carnegie Inst. Wash. Pub. 280. 1919. 2 Benedict, F. G., and Ritzman, E. G. Undernutrition in steers: its relation to metabolism, digestion, and subsequent realimentation. Carnegie Inst. Wash. Pub. 324. 1923. s Lusk, G. The physiological effect of undernutrition. Physiol. Rev. 1, 523. 1921. "Gulick, A. Weight regulation in the adult human body during overnutri- tion. Amer. Jour. Physiol. 60, 371. 1922. "'Means, J. H. The basal metabolism in obesity. Arch. Int. Med. 17, 704. 1916. e Strouse, S., Wang, C. C., and Dye, M. Studies on the metabolism of obesity. II. Basal metabolism. Arch. Int. Med. 34, 275. 1924. 1928] ALFALFA, CLOVER, AND TIMOTHY HAY FOR SHEEP 143 basal metabolic rates, and Blunt and Bauer 1 have found that among a group of nineteen college women who were underweight by compari- son with life insurance standards and were eating hardly enough food to supply their estimated daily needs, the basal metabolic rate aver- aged almost normal. Also Morgulis, in his book on "Fasting and Undernutrition," 2 cites an experiment performed in Benedict's labora- tory on a dog, in which a restriction in diet, causing a sharp drop in body weight, was not associated with a drop in basal metabolism per kilogram body weight. It seems fair to conclude that while underntitrition may ultimate- ly lower the basal heat production of an animal, there are conditions that may defer or obscure this result for considerable periods of time. Until more is known of these conditions, the result of undernutrition in any particular case cannot be foretold with any degree of certainty. In the foregoing experiment on sheep described in this bulletin, the timothy-hay sheep were undernourished during the first few weeks of the experiment. If this undernutrition had lowered their energy re- quirements, 3 it would be expected that the amounts of metabolizable energy ultimately shown to be required for maintenance of weight would be inversely correlated with the losses in weight sustained. That this is not the case is shown by the following comparison: Metabolizable energy required Sheep No. Average Average Loss in per 100 pounds initial weight final weight weight average live weight Ibs. Ibx. Ibs. cals. 164 105 87 18 1 168 166 116 99 17 1 534 167 Ill 98 13 1 600 168 101 94 7 1 633 165. . 99 94 5 1 598 'Blunt. K.. and Bauer. V. The basal metabolism and food consumption of underweight college women. Jour. Home Econ. 14, 171, 226. 1922. 2 Morgulis. S. Fasting and undernutrition: a biological and sociological study of inanition, 226. E. P. Button & Co. 1923. 3 It is of course recognized that these requirements relate to voluntary mus- cular activity as well as to basal metabolism. The above discussion has been necessarily confined to the effect of undernutrition on the basal metabolic rate since no quantitative information has been found concerning its relation to voluntary activity. However, the experiments reported by Trowbridse. Moulton, and Haigh (Mo. Res. Bui. 18), on the live-weight maintenance requirements of cattle, may be cited in this connection. In these long-continued maintenance trials no effect of the condition of the steers can be detected when all of the data are considered; in particular a restricted food intake induced a somewhat higher maintenance cost per unit of area in the average (Tables 23 and 24, and con- clusion 9). The later calculations of Hogan, Salmon and Fox (Mo. Res. Bui. 51, 1922) on growing and fattening steers, leading to the conclusion that the main- 144 BULLETIN No. 317 [December, The sheep are arranged in the order of decreasing losses in weight, and it is evident that, disregarding the exceptionally low result for Sheep 164, x there is no progressive or considerable increase in energy requirements with decreasing losses in weight. It is frankly admitted, however, that the results obtained with the timothy-hay sheep may not be strictly comparable with those obtained in the other lots for the reasons explained above, and while it seems very unlikely that the conclusion drawn from the comparison is vitiated, it was considered advisable to repeat the alfalfa hay-tim- othy hay comparison in a second experiment planned to meet so far as possible the objections that may be raised against the first. SECOND EXPERIMENT: ALFALFA AND TIMOTHY HAY Outline of Experiment It was realized at the outset of this experiment that it would be difficult to induce sheep to consume enough of a ration consisting largely of timothy hay to maintain weight. It was, therefore, planned to start two groups of sheep, one to receive a timothy ration and one an alfalfa ration, and to limit the food consumption of the alfalfa-hay sheep, if necessary, so that they would exhibit the same losses in weight as the timothy-hay sheep. At the end of 15 weeks the rations were to be changed, each sheep receiving as much of the second ration as it had been consuming of the first. Nineteen western wethers and one ewe, averaging 93 pounds per head, were obtained in February, 1926, for this experiment. Six were slaughtered on February 23 and analyzed to determine the initial composition. The remaining 14 were divided into two lots, one to be fed the alfalfa ration and one the timothy ration. The timothy-hay sheep were later reduced to six, since one proved to be a poor feeder. As in the first experiment, the sheep were individually fed and received in addition to the roughage approximately .08 pound of lin- seed oil meal daily per 100 pounds initial body weight, All sheep had access to salt at all times, and when consuming timothy hay they also received a small amount (6 grams) of steamed bone meal daily. The individual feeding crates are illustrated in Fig. 1. tenance energy cost increases with the plane of nutrition, are of less certain sig- nificance since the energy storage in the gains had to be estimated and, in par- ticular, since the assumption is made that the net energy value of feeds is the same at different levels of feeding. This assumption cannot be justified by ex- perimental findings and for low and high levels it is incorrect in all probability. n Xo digestion and metabolism experiment was run on this sheep. The aver- age results of the other four sheep were used in the calculation of the metaboliz- able energy content of the maintenance ration in this case. 1928} ALFALFA. CLOVER, AND TIMOTHY HAY FOR SHEEP 145 It was found that the timothy-hay sheep would not consume con- tinuously more than 1 pound per head daily, and on March 1 the feeding experiment began with this group at this level. The alfalfa- hay sheep were started at 1.5 pounds of hay daily per head, but were later reduced to 1 pound also, since on the higher level they gained in weight. All sheep lost slowly in weight on 1 pound of roughage daily, but the losses in the two groups were very closely the same. During May and June all sheep were subjected to a digestion and metabolism trial lasting ten days, during which there were no feed residues. On June 2 the sheep were sheared and on June 14 the ra- tions were reversed. After the change in ration all sheep continued to lose slowly in weight, and in July the first deaths occurred among those receiving FIG. 1. THE INDIVIDUAL FEEDING CRATES USED IN THE EXPERIMENT alfalfa hay. In this group two sheep died on July 12 and 13 respec- tively, and one on August 19. On September 13 the remaining three sheep on the alfalfa ration were again put in the metabolism crates for a ten-day period, immediately after which two of them died with no apparent symptoms but those of malnutrition. The remaining sheep was slaughtered and analyzed on September 27. Among the sheep receiving timothy hay in the second period of the experiment, no deaths occurred until September, when three died on the 16th, 19th, and 24th, respectively. The remaining four sheep were put into the metabolism crates for ten days and were then slaughtered, one on September 27 and three on October 4. 146 BULLETIN No. 317 [December, Results of the Second Experiment Chemical Composition of the Check Sheep. The live weights, empty weights, and fill of the six check sheep, slaughtered at the be- ginning of the experiment, are given in Table 13. An average of 72 percent of the "fill" was contained in the first three stomachs. The average weight of wool shorn from the sheep before slaughter was 5.5 pounds. The average weight of blood collected was 4.06 pounds, and the weights of caul fat and gut fat averaged 2.03 and .98 pound re- spectively. The dressing percentage ranged from 44.4 to 50.3, aver- aging 47.8. TABLE 13. LIVE WEIGHT, EMPTY WEIGHT, AND FILL OF CHECK SHEEP Sheep No. Live weight Empty weight Fill Fill 34 Ibs. 70.1 lb. 62.2 Rw. 7.9 perct. 11.2 50 91.2 79 3 11 9 13 1 11 116. 1 100.6 15.6 13.4 30 83.2 70.3 12.9 15.5 12 . 97.2 87 3 9 9 10 2 44 88.9 78.9 10.0 11.2 Average 91.1 79.8 11.4 12.4 The entire carcass of each sheep was divided for analysis into three samples: (1) the flesh sample contained the boneless meat on one half of the dressed carcass, including one kidney, the left half of the carcass not being analyzed ; (2) the bone sample included the bones of one half the dressed carcass, separated by knife, and the bones of the head and of two of the feet; and (3) the offal sample, made up of the blood, the hide, the flesh on the head, the abdominal fat, and all of the viscera with the exception of the kidneys. The wool of all six sheep was composited for analysis. The weights of these samples from each sheep and the aver- ages for all will be found in Table 14, while the results of their chemi- TABLE 14. WEIGHTS OF SAMPLES ANALYZED (FRESH BASIS) CHECK SHEEP (All weights in kilograms) 34 50 11 30 12 44 Average 11.20 15 87 21.50 13.09 18.02 16.22 15.98 3.92 4.41 5.03 4.15 4.76 4.37 4.44 Offal samples 8.52 12.79 13.66 9.83 12.02 10.41 11.21 cal analysis are given in Table 15. Besides the ordinary routine de- terminations the calcium was determined in these samples by the method of McCrudden 1 and the gross energy by combustion in the Pan- oxygen bomb calorimeter. From these sample analyses the composition of the entire car- casses of the sheep has been calculated on the basis of the empty McCrudden, F. H. Jour. Biol. Chem. 7, 83, 1910; 10, 187, 1911-12. 1928] ALFALFA, CLOVER, AND TIMOTHY HAY FOR SHEEP TABLE 15. PERCENTAGE COMPOSITION AND ENERGY CONTEXT OF SAMPLES FROM THE CHECK SHEEP 147 Sheep No. Dry substance Total nitrogen Crude protein Ether extract Ash Calcium ^rgy uram Edible-flesh samples 34... 3S . 24 3.02 18.88 16.61 .96 . 022 .-m. cals. 2 536 50 ... . 4."> 77 2 . 57 16 06 27. (19 . SO 027 3 330 11 57 . 50 2 . 28 14 . 25 40 . 05 .69 .019 . .M 30 . . 40 84 2 79 17 44 23 OS 94 ', i Q2 12 ."2 77 2.58 16.13 30 27 .81 017 3 44 50.32 2.47 15.44 3 i . NS .75 .025 oil Average 47.99 2.62 16.37 28.66 .84 . 023 3 514 Bone samples 34 59 66 3.29 20 . 59 is. 31 18.50 I > s54 50 . . 59 71 3.46 21.62 20.04 17.34 6 4>; 2 836 11 61.14 3.49 21. S3 17 . 58 20.09 7.50 2 828 30 5 95 3 4S 21 77 17 71 18 32 6 M 2 v>3 12 . . BO. 88 3.45 2 1 . 5s 20 . 37 17.99 6 98 3 042 44 65.00 3.31 20.68 21.88 20.56 7.73 3 169 Average 60 . S9 3.41 21.35 19.32 18.80 7.07 2 925 Offal samples 34... 30. So 34 . 34 40 . 64 30.12 37.49 41. SO 35 ^7 2.70 2.33 2.34 2.50 2 . 68 2.21 2.46 16.86 14.58 14.65 15.62 16.75 13.81 15.38 12.57 17.91 23 . 95 12.71 lv. Mi 25.97 ls.66 1.05 .87 .94 1.09 .95 .73 .94 .035 .034 .032 .038 !627 .033 2 119 2 501 _' 960 2 149 2 651 3 2S4 2 611 50 11 30 ... 12 44 Average Wool sample 94.74 9.31 58.19 21.85 14.7 . 250 5 756 TABLE 16. PERCENTAGE COMPOSITION AND GROSS ENERGY CONTENT OF THE CHECK SHEEP Sheep No. Live or empty weight Dry substance Crude protein Ether extract Ash Calcium Gross energy per gram On basis of live weight 34... A'ffs. 31.80 36.51 IS. 26 13.19 4.05 sjn. cals. 2 263 50 11 41.39 52.68 40 . 22 44.32 16.47 14.45 19.37 25 . 27 3.33 3.14 .72 .74 2 ti'.K 3 147 30 37.76 34.72 16.34 14.70 3.59 .78 2 300 12 44.11 43 69 16 77 20 94 3.36 .77 2 S74 44 40.32 43 . 93 15.61 24 . 46 3.63 .87 3 162 Average 41.34 40.57 16.32 19.66 3.52 .SO 2 741 On basis of empty weight 34 . . 28.23 41 12 20 . 57 14. S6 4.56 1.00 2 519 50 35.97 46.28 IS. 9! 22.29 3 . S3 ! 3 102 11 45.61 51.19 16.69 29. IS 3.62 .86 - 30 31.91 41.09 19.34 17 39 4.25 .93 2 722 12 39.62 4S.64 1 S . 67 23.31 3.74 .86 3 200 44 35.80 49.48 1 7 . 5S 27.54 4. os - 3 561 Average 36.19 46.30 18.63 22.43 4.01 .91 3 128 weight and of the live weight, given in Table 16. The results of these calculations are 148 BULLETIN No. 317 [December, Gross energy per grain O l>- X C^ ' (^ C IB g co co co co * *j< >} X r- i ' i X Oi Oi O re re re ^ X IB iB IB CO -f X re -H t~ x to o ' C5 X Ci C3 O C O _a O IB 1 IB -1 O5 CC re re >B -^ as IB re IB ' iB h~ r-wooc-j-iB CO CO CO t^ CO t^ t^ IB >B iB iB IB IB iB y. o K extract Cl X X B O "^ CO re "^ ^ IB N X i -~ * re re re re CS X X O cc co c: C X o w c 'c 'o L. < o c o re IB -^ t^ 3 CO '"- X O CO t^ CO iB c s IB CN o re IB TJ< ft CO CO CO "B -* 10 IB CO COf CO ^ T)l * TJIIB ^J< * z s i i o s astanee ssssggfcsg 0^--H t^ C<1 -^ ^ -^ t>. ^ CO X t^ CO ^ CO 1 1 H 3 3 recor^xreoo X X X X Oi OS C5 xxxx O2 X X X CT. if. C! H O 2 C. i o" t"co^ v ''^'-^"c> . .re - -co 00 ^,^, cc'rt _ ^ x" ^^-.^ .-- 660 2 . .333 . PC O CO GC _. 5 . . c-i - - "] "*' : 2 : ~ >.~~ 3 ll'll'li X l~^^ * x '^ 2 3 "3 = O Mar. 1-Apr. 2 Apr. 2-May 1 May 1-JunG 2 June 2-June 14. . . . Mav 12-May 22'. . May 23-June 2 1 . . . June 4-June 14'. . . 1928} ALFALFA, CLOVER, AND TIMOTHY HAY FOR SHEEP 149 a S H ' CO to O >O OO50000O ^ lO ^HI [>. ^0 t^- r-t M* 'O C*t h* O t to 00 t^ lO Oi 'C CO b- 10 O * .-i O f t- -< h- i? O CO rC CD *N o t** o oil mea CO CO CO CO CO CO CO oil mea! CO CO "O lO IO 1C co co co co co co ig their r SSSSS i X O to -i * to 'O CO 'O O X O3 O CN c ^* X "f to ^f to "O >O O O CO -^ t- CO CO i-i Tf Tt< CO CO CO CO CO CO CO CO CO CO CO CO CO CO J> O TJI CM CO 00 lO CN CN 'O b- O O O OJ tS M CO -I C 1^ CC to C o '.; o x cb x o ~o XC2 XOOOO 00000000 00 01 o ^ c; o c^ ci C5 O Cl X wl C^ X O GJ X t*- X f^ XXX 00 WOO i was als( 8> -co co s ^_O^^ . I 50 . CO _E M B CO c c o o >ds. 'This sampl< ft l-~ *ij$i i -5 t^ < O5 O! tl T a 7 S" c "^ "H 6^ "^ C* iH N N l^|o9 'Metabo 150 BULLETIN No. 317 [December, The sheep were evidently not uniform in composition. The heavier individuals were in good condition since they contained 20 to 25 percent of fat, but the lighter individuals were considerably less fat. Feeding Period and Changes in Body Weight. During the feed- ing of the other two groups of sheep at the barns, samples of the feed were taken daily and composited for analysis at approximately monthly intervals in so far as possible. In addition to these samples were those taken during the metabolism periods. The percentage com- position of all samples is summarized in Table 17. The individual feeding of the sheep started on February 22, but the first week was considered as preliminary in character. The sheep of Lot 1, consuming the timothy-hay ration, were adjusted to a daily intake of 1 pound of hay per head and .08 pound of linseed oil meal per 100 pounds initial body weight by March 1, but the sheep of Lot 2 were given 1.5 pounds of hay until March 2, when the ration was cut to 1 pound of hay per head and .08 pound of linseed oil meal per 100 pounds initial body weight in view of their rapid gain in TABLE 18. WEEKLY BODY WEIGHTS OF THE SHEEP IN LOT 1 (All weights in pounds) Sheep No 2 | 3 6 8 10 11 Average Period I Timothy hay Feb. 22 78 85 103 83 96 98 90 5 Mar. 1 69 77 92.5 67.5 87 86 79.8 8 71 75 5 91 5 71 87 88 80 7 15 .... 73.5 77.5 96 73 90 87 82 8 22 73 76.5 93 70 85 83 80.1 29 74 78 86 71 86 83 79 7 April 5 70 74 85 70 86 82 77 8 12 72 75 88 71 87 83 79.3 19 . 71 73 86 68 85 79 77 26 75 76 87 70 87 80 79 2 May 3 68 74 90 69 86 78 77 5 10 70 72 86 67 S3 74 75.3 17 74 75 So 68 87 76 77.5 24 65 69 8.3 72 86 75 75 31 ... 70 74 82 65 82 77 75 June 7 63 58.5 74 58.5 74 70.5 66.4 14 70 67.5 78 67.5 79 70 5 72 1 Average 69. 6 1 72. 3 1 85. 3 1 67. 8 1 83. 8 1 78. 4 1 Period II Alfalfa hay June 14 632 60 2 69" 61 2 712 62' 64. 3" 21 63 58 65 60 68 65 63 2 28 .. 61 60 66 62 70 63 63.7 July 5 61 63 71 64 73 65 66.2 12 58 47 64 60 68 63 60.0 19 60 Died 7-12 69 60 Died 7-13 65 26 57 63 59 61 Aug. 2 57 63 59 61 9 57 64 57 62 16 58 66 54 62 23 56 62 Died 8-19 61 30 55 61 58 Sept. 6 53 65 58 13 52 60 56 14 52 58 57 23 51 58 55 Average 57.3 57.6 64.2 59.3 70.0 61.0 "The sheep were sheared on June 2, but the weights given on June 7 and 14 include the wool weights. In the averages, however, the sheared weights on these dates have been used. 'Sheared weights. 1928} ALFALFA, CLOVER, AND TIMOTHY HAY FOR SHEEP 151 weight. The experimental period with this lot was not considered as starting until March 22. The weekly weights of the sheep thruout the two periods of feeding will be found in Tables 18 and 19. TABLE 19. WEEKLY BODY WEIGHTS OF THE SHEEP IN LOT 2 (All weights in pounds) Sheep No 1 4 5 7 I 9 33 60 Average Period I Alfalfa hay Feb. 22 84 78 79 83 SO 80 79 79 78 79 75 72 76 70 78 74.5 75.5 75.21 83 72.5 76.5 78 74 74 72 73 70 73 70 69 72 67 74 62.5 67.5 69.01 87 82 81.5 85 80 78 77 78 77 77 77 75 77 75 75 66.5 71.5 74. 4 1 99 90 90.5 93 89 87 88 86 84 85 82 80 81 84 78 72.5 76.5 81.41 86 78 80.5 86.5 82 82 80 81 78 80 76 75 74 74 72 67.5 72.5 75.51 82 71 76 75 74 74 73 76 73 75 75 68 71 70 74 68 68 70.81 102 90 92 96 90.5 88 87 88 85 86 84 80 82 82 83 75.3 75.3 82.21 89 80.1 82.3 85.2 81.4 80.4 79.4 80.1 77.9 79.2 77.0 74.1 76.1 74.6 76.3 69.5 72.4 Mar 1 8 15 22 29 Apr. 5 12 19 26 May 3 10 17 .... 24 31 June 7 14. .. .. Average Period II Timothy hay 66 J 57 2 63* 69* 66 59" 67 63.9 21 64 58 60 69 65 62 70 64.0 28 61 60 64 71 64 61 70 64.4 July 5 66 62 65 77 70 63 70 67.6 12 64 55 61 72 61 58 69 62.9 19 65 61 66 65 67 60 69 64.7 26 .... 59 55 61 65 60 58 65 60.4 Aug. 2 60 54 61 63 60 58 65 60.1 9 62 54 61 65 61 59 66 61.1 16 61 58 66 69 64 62 68 64.0 23 63 56 63 67 64 62 67 63.1 30 60 51 60 62 59 56 63 58.7 Sept. 6 59 53 62 63.5 59 56 62 59.2 13 59 51 60 60 56 55 60 57.3 20 60 51 60 Died Died 24 57 52 59 9-16 9-24 53 Died Oct. 3 58 50 59 9-19 Average 61.4 55.2 61.8 66.8 61.9 58.9 66.1 ] These averages include the period starting with the weight of March 22. They also include the shorn weights of June 7 and June 14 instead of these weights plus the wool removed on June 2, as given in the table. 'Sheared weights. Amount and Composition of Wool Sheared at End of Period I. On June 2 all sheep were sheared, the individual weights of fleeces being as follows: Lot 1 Timothy No. 2 Ibs. 70 3 7.5 6 9.0 8 6.5 10 8.0 11.. ..8.5 Average 7 .75 Lot 2 Alfalfa No. 1 Ibs. 9.6 4 10.5 5 8.5 7 7.5 9 ... 6.5 33 8.0 60. . . 8.3 Average 8 .40 152 BULLETIN No. 317 [December, The wool from the alfalfa sheep averaged slightly heavier per head, but the lot difference is certainly not significant. The wool from each lot of sheep was composited and analyzed as a separate sample, with the following results: Dry Total Crude Ether matter nitrogen protein extract Wool from timothy sheep SS.56 7.79 48.69 22.44 Wool from alfalfa sheep 91.00 7.95 49.69 22.02 Ash 11.89 13.73 Gross energy (sm. cals. per gm.) 4 907 i 5 068 ('Estimated from chemical composition, assuming the gross energy values of protein and fat to be 5.7 and 9.5 calories per gram respectively.) Apparently there was no significant difference in the percentage composition as well as in the weight of the wool from the two lots of sheep. Digestibility and Metabolizable Energy Content of Rations. The digestion and metabolism trials inserted at the end of the two experi- mental periods yielded information relative to the digestibility of and the content of metabolizable energy in the two rations. The co- efficients of digestibility obtained from these data will be found in Table 20. The timothy-hay ration was evidently considerably less di- gestible than the alfalfa-hay ration with respect to dry matter, crude protein, and nitrogen- free extract. On the average the dry matter of the timothy-hay ration was only 82 percent as digestible as that of the TABLE 20. SUMMARY OF DIGESTION COEFFICIENTS Sheep No. Dry substance Crude protein N-free extract Crude fiber Ether extract Alfalfa, oil-meal ration Period I 1 60 73 67 51 37 Period II 4 5 7 9 33 60 2 58 57 53 54 53 54 56 70 69 68 73 70 70 72 66 66 62 62 61 63 61 47 45 33 35 37 36 49 32 35 44 43 26 35 55 Average 6 11 60 58 56.3 77 72 71.4 64 65 63.7 52 53 43.8 44 55 40.6 Timothy, oil-meal ration Period I 2 49 53 56 42 53 Period II 3 6 8 10 11 1 46 44 47 48 37 50 45 38 32 38 27 40 53 51 56 57 46 57 42 41 45 45 33 52 62 45 51 47 32 49 Average 4 5 33 46 48 48 46.3 30 37 40 38.0 55 57 57 54.5 46 53 49 44.8 29 33 36 43.7 1928} ALFALFA, CLOVER. AND TIMOTHY HAY FOR SHEEP 153 J ii 5 -< Cl l :O *t< ;O -* GO >O O h- (N I-H t^. CS O SO rt< C^ O X TJ* i>3 ^* t^. X O *~^ ^1 ^1 "O t^- *O C*l O3 CO tO CS t^- -t CO -1* CS CS CD .) c! a^^i5^5??5 ^>??^ CO CO CO CO CO CN ^rcorcroS B ^- CO XI Cg O X * O ? r- 'M O i o t~ to cs r^. o t^ t^ -r ~ csr^'O i^cs oo-fcoo i ^> iO >O *O T}< -* ^ ** iO >O 'O *O P, -.t '? ..-: to to -* cs co co -^ o 1 o e.S "o CO *O t- O O C CO Ot^-fO X X I-H CO O f- / rt cs I 2 I e ^ iO iC iO O O O '0 10 '.. .. CO CO CO CO CO CO Ol Ol CO T-1 CO - ^.jiSgaSSg ooo s 01 1^ -f oi x -H cs x i o x o 01 1^ o >o co co t^- o t^ X 1 *s i i i i CO to 1 O CD O t X i i CO Ol t 1C O) i * O -t -^ OJ CO _2 jf 2 X CO CO 00 to O X CO CN t- t- C IMp^HXCNCOCO O "O 1 CO co cs 10 < r-- n -* to -j 01 co COOJCOCOCOC1 ^tcOCOCOCO N X be P-l ~ * co co co co co co co cocococo cocococococo cococococo Jj ill S so a ^ coxt^xxxx xot^x 01 01 -0 01 i-O i-i t~ O O C5 ^comiOTttco -t-r-rco-fi P-. o B 5 co co co co co co co co-^coco cocococococo cococococo pi M 2 O- X O CO Ol O CO to O X h- ft i I i I O t^- CO i ~^ OOCO^f 'C co co r^ x 01 x o -t t^ -^ . f c inattt V aiil iav ra O to i to X CS t^ X O O OJ 10 1"* CO CO "I X to X "X :O Ol Ol O) Ol Ol CM Ol Ol Ol O) O4 S CD - ^3 o | 1 a c a o3 2 (Nib-oxTfo c-i-^o^ a ^ 'O >O t-- CD ?C ^t 4 CO O 'O *O a iO >O iC CO ^f CO O -O h* Ol CS COCOCOCO-*CO 0101COCOCO o 3 ~ a fe 9 2 1 'f rf O 1 CO 00 t^tO^ft^ ft COCDCOt -HXcO 1 CO i-l "3 J^ XXC5OOOO OtC3CS f i-l Ol O Ol -f -t CS CO CS T i^irt-proco oi 1 10 oi>^ ci co ^i 01 01 x 01 -r 01 co co c ^ ^^^^NCIINO) C-JrH^-, 01 01 01 01 0, 01 01 01 01 01 01 3 'o 1 ooxco>ot~r^co so oo oo oo -f * t^ x t~ r~ o to co cs x co co co co co ^ t -* -r * co ~ r " TJ "^ 1 " 1 "* < ^ ^^^^ a- o c! a a CD 1 c g . ^ -f CS Cl -if CO CS COXXcD 0, CM IN 01 (N CN Co o t^ t-~ i -^ o t^- o o r>- 'O t* t^ .3 ooocooo oooooo ooo ooooooo s o o o tt g 03 o oo 30 o o o t^ os o cs ib c-j ^ OO5OSOO3SO OiOSOSOSOSCS : CO o S3 si STj 3X) 5.SP -IliSSISI Sssi 00 01 B < : 3- H ^ a 02 a) jj v M o M : : : g 1 "S ::::::: ^ . . > ja : : : : : K- 3j Wcs'co' -<: 'N'^OX '^ 3 rt "" ' ' " S s^" rtrt < H ^:> x?> ieiJJ 1 * 1 s^.oVos'Mo'*' 3 ^ 1-1 S coco < H 1928] ALFALFA, CLOVER, AND TIMOTHY HAY FOR SHEEP 161 of animals of different sizes are best equated and compared by surface ratios; but in so far as they consist of energy expenditures in volun- tary muscular activity, differences in size are best removed by weight ratios. In the present case both factors are involved and it seems im- possible to decide which method is the better. By both methods of computation, the timothy-hay sheep con- sumed about 20 percent less metabolizable energy than the alfalfa- hay sheep and yet their loss in weight was no greater. The conclusion seems warranted, therefore, that the metabolizable energy of the timo- thy-hay ration was considerably better utilized, i.e., possessed a higher percentage availability, than the metabolizable energy of the alfalfa- hay ration. There is a close correlation in each group between the average loss in weight and the average intake of metabolizable energy per 100 pounds live weight. This correlation is approximately linear in char- acter and may be expressed by the equation of a straight line. For the two sets of data relating to the energy consumed per unit of weight and for the two groups of sheep, the equations that were fitted to the data best by the method of least squares are: Alfalfa-hay sheep Weight ratio: y = .438 - .000317x (1) Surface ratio: y = .506 - .000419x (2) Timothy-hay sheep Weight ratio: y = .379 - .000330z (3) Surface ratio: y = .409 - .000401z (4) in which y is the average daily loss in body weight in pounds, while x is the average daily intake of metabolizable energy per 100 pounds body weight in calories. In Table 29 the sheep in each group are ar- ranged in the order of decreasing intakes of metabolizable energy per 100 pounds of weight for comparison with the actual average losses in weight and those computed by the above equations. By the use of equations (1) to (4) it is possible to compute the metabolizable energy requirements for maintenance of body weight by solving for x when y = o. For the alfalfa sheep these estimated requirements are 1,382 calories per 100 pounds body weight, using the ratio of weights, and 1,208 calories, using the ratio of surfaces. For the timothy-hay sheep these estimated values are 1,149 and 1,020 calories respectively. These values should not be confused with en- ergy requirements for energy equilibrium, since immature sheep, such as these were, would probably be in negative energy balance even tho the weight were constant. The data of Period II are less complete than those of Period I because of the death of three of the alfalfa sheep shortly after the period started. The daily losses averaged somewhat less in this period than in the preceding, but the amounts of food consumed per 100 pounds weight were much larger, so there is no need for assuming that 162 BULLETIN No. 317 [December, TABLE 29. CORRELATION OF INTAKE OF METABOLIZABLE ENERGY AND AVERAGE Loss IN WEIGHT IN PERIOD I Sheep No. Metabolizable energy consumed daily Average losses in weight Actual Computed by Weight ratio Surface ratio Equations 1 or 3 Equations 2 or 4 Alfalfa-hay ration 4 Ibs. 1 241 cals. 1 097 Ibs. .054 Ibs. .044 Ibs. .047 1 1 153 1 048 .059 .072 .068 5 1 132 1 026 .089 .078 .077 33 1 094 974 .060 .090 .099 9 1 061 966 .117 .101 .102 60 985 923 133 .125 .120 7 967 903 .129 .131 .128 Timothy-hay ration 8 1 070 940 .029 .026 .032 2 1 013 897 .014 .045 .049 3 941 844 094 .069 .071 10 852 HI 803 098 .098 .087 6 727 689 .168 .139 .133 11 632 582 .145 .171 .176 the sheep were adjusting themselves to a lower level of energy expen- diture. In fact quite the reverse is indicated. Of the three alfalfa sheep two showed smaller losses in weight than in the preceding period on timothy hay, while of the seven timothy sheep four showed smaller losses than in the preceding period on alfalfa hay. The average daily intake of feed again averaged slightly less for the timothy-hay sheep than for the alfalfa-hay sheep, while their intake of metabolizable energy was considerably less. Per 100 pounds body weight the metabolizable energy consumed was much smaller in amount for the timothy sheep than for the alfalfa sheep. The data of Period II therefore confirm those of Period I in indicating a greater availability of the metabolizable energy of timo- thy hay than of alfalfa hay. On June 15, at the end of Period I, the lightest and heaviest sheep in each group were photographed against a checkered back- ground, with the results pictured in Figs. 2 and 3. The alfalfa sheep appear to be in somewhat poorer condition than the timothy sheep. In early August, near the end of the second period, group pictures were taken of four sheep from each lot (see Figs. 4 and 5). These pictures are of value mainly in showing the wool growth that has oc- curred since the shearing on June 2. Since the losses in weight of the alfalfa-hay sheep were as great as those of the timothy-hay sheep, it seems fair to assume that, thru- out this experiment, their energy requirements were approximately the same per unit of weight or surface. Since it required more metaboliz- able energy from alfalfa hay than from timothy hay to maintain such 1928} ALFALFA, CLOVER, AND TIMOTHY HAY FOR SHEEP 163 FIG. 2. SHEEP 7 ABOVE AND SHEEP 4 BELOW WERE IN LOT II WHICH RECEIVED ALFALFA HAY The photographs were taken on June 15, at the end of Period I. No. 7 was the heaviest sheep and No. 4 was the lightest in the alfalfa hay lot at this time. equal nutritive states in sheep, the metabolizable energy of timothy hay must therefore be considerably better utilized in the body. Summary of the Second Experiment A comparison of the value of timothy hay and alfalfa hay as sources of energy has been made in feeding experiments on sheep. Two groups of yearling western wethers, weighing from 80 to 100 pounds, were placed, one group of seven sheep on a ration of alfalfa hay and linseed oil meal and the other group of six sheep on a ration 164 BULLETIN No. 317 [December, FIG. 3. SHEEP 10 ABOVE AND SHEEP 3 BELOW WERE IN Lor I WHICH RECEIVED THE TIMOTHY RATION The photographs were taken on June 15, at the end of Period I. No. 10 was the heaviest sheep and No. 3 was the lightest in the timothy-hay lot at this time. of timothy hay and linseed oil meal. When it was found in this ex- periment, as in the preceding one, that the timothy hay was not being consumed in amounts sufficient to maintain weight, the intake of al- falfa hay by the other group was likewise restricted so that the loss in weight on both rations was approximately the same. One pound of timothy hay per head daily was as much as would be cleaned up con- sistently, and one pound of alfalfa hay daily proved to be equally efficient in preventing loss in w r eight, so this amount was offered daily thruout the experiment to all sheep. In addition each sheep received .08 1928] ALFALFA, CLOVER, AND TIMOTHY HAY FOR SHEEP 165 pound of linseed oil meal daily per 100 pounds initial live weight. Salt was available to all sheep and a small amount (6 grams per head) of steamed bone meal was given to the sheep on the timothy ration. All sheep were fed individually. After 100 days of feeding the sheep were sheared. At about this time or earlier a digestion and metabolism experiment was run upon each sheep. At the end of 112 days of feeding the rations were reversed, those sheep getting alfalfa hay being put upon timothy hay. and vice versa. This second period lasted 112 days, and during the last few weeks digestion and metabolism trials were made upon all surviving sheep. Six sheep, purchased at the same time and of the same age, breed- ing, and condition as the experimental sheep, were slaughtered at the beginning of the experiment in order to obtain a definite idea of the initial nutritive condition of the sheep subsequently fed. On the live- weight basis they were found to contain, on an average, 40.57 percent of dry matter, 16.32 percent of protein, 19.66 percent of fat, 3.52 per- cent of ash, and .80 percent of calcium. Their "fill" averaged 12.4 percent of their live weight. The wool sheared from the sheep on June 2 was approximately the same in amount and composition for the timothy and for the alfalfa sheep. All sheep decreased in weight from the beginning to the end of the experiment. The losses on the alfalfa ration were of the same order of magnitude as those on the timothy ration, and in each period the average losses were very nearly the same. Evidently, so far as may be judged from the changes in weight of the sheep, one pound of the alfalfa hay used was equal in energy value to one pound of the timothy hay used. The digestion trials, however, showed conclusively that the alfalfa ration was much more digestible than the timothy ration. On an aver- age, the dry matter of the timothy ration was only 82 percent as di- gestible as that of the alfalfa ration, the crude protein was only 53 percent as digestible, and the nitrogen-free extract only 86 percent as digestible. The digestibility of crude fiber and ether extract was not greatly different for the two rations. For the same weight of dry matter the timothy-hay ration con- tained only 79 percent as much metabolizable energy as the alfalfa- hay ration. An average of 45.5 percent of the gross energy of the al- falfa ration was metabolizable, while only 36.9 percent of the gross energy of the timothy ration was metabolizable. The prevailing nitrogen balances on both rations were negative, this being true of all of the balances obtained on the timothy ration. The average nitrogen balance was -.15 gram per day on the alfalfa ration and -1.47 grams per day on the timothy ration. 166 BULLETIN No. 317 [December, FIG. 4. FOUR OF THE SHEEP OF Lor I, PHOTOGRAPHED EARLY IN AUGUST WHILE ON THE ALFALFA RATION The picture shows the active growth of wool since early in June, on the markedly submaintenance ration. Five of the six sheep on the alfalfa ration in the second period died of undernutrition before the termination of the experiment, while only three of the seven sheep on the timothy ration succumbed. The FIG. 5. FOUR OF THE SHEEP OF LOT II, PHOTOGRAPHED EARLY IN AUGUST WHILE ON THE TIMOTHY-HAY RATION This photograph shows also the active growth of wool on a submaintenance ration. H.>,?S\ ALFALFA, CLOVER. AND TIMOTHY HAY FOK SHKKI- 167 surviving five sheep were slaughtered and analyzed. They were found to be in an extremely emaciated condition, the fat stores being prac- tically depleted. On the live-weight basis they contained an average of only 4.6 percent of fat. Three of the five sheep still retained considerable fat in their bones, indicating that marrow fat is among the last of the fat stores to be depleted in undernutrition. The two sheep showing inconsider- able amounts of fat in the bones were the most emaciated of the group. The withdrawal of fat from the tissues was accompanied by an increase in moisture on the fat-free basis, so that the ratio of protein to moisture, particularly in the muscles and in the bones, was greatly decreased by undernutrition. The wool sheared from these sheep, however, did not differ greatly in composition from the wool of the check sheep, even in its content of fat. Computations of the rate of deposition of protein and energy in the wool during more than 200 days on a submaintenance ration, indicated that it was normal as compared with similar data collected from sheep on production rations. The physical characteristics of the wool unfortunately were not studied. During this protracted period of normal wool growth on submain- tenance rations, the bodies of the sheep lost 71.2 percent of their fat content. 47.7 percent of their gross energy content, but only 6.6 per- cent of their protein content. The data in both periods proved that, for apparently equal degrees of undernutrition, 20 percent less metabolizable energy was required in the timothy ration than in the alfalfa ration. Conclusions of the Second Experiment The metabolizable energy of timothy hay is considerably better utilized in the maintenance of sheep than is the metabolizable energy of alfalfa hay. Since, in general, the metabolizable energy per unit of dry matter is nearly the same for the two hays, the net energy con- tent of timothy hay will average considerably higher than that of alfalfa hay, in accordance with the results of Armsby's calorimetric experiments on steers. Undernutrition withdraws fat from the muscular and glandular tissues before the marrow fat is affected. The withdrawal of fat from all tissues is accompanied by an increase in the ratio of protein to moisture. Neither the composition of the wool, however, nor its chemi- cal growth is greatly affected by undernutrition. -- ^ V // HH JB >r\ v "VERSITYOFILLINOIS-URBANA