1 A2S THE UNIVERSITY OF ILLINOIS LIBRARY G"50.7 v\_o . "3 -*> 2-3 CHEC UNIVERSITY OF ILLINOIS Agricultural Experiment Station BULLETIN No. 323 SWINE TYPE STUDIES III. THE ENERGY AM) PR )TK!\ R1XH I RI-.MKNTS OF GROWING S\VINK AM) THK ITIU/ATION OF FEED ENERGY IN GROWTH Bv II. II MITCHKI.L and T. S. HAMILTON IKBANA, ILLINOIS, MAY, 1929 CONTENTS (PART III) PAGI GENERAL PLAN OF THE EXPERIMENTS 49.' FIRST EXPERIMENT 49i Composition of the Control Pigs 49J The Maintenance Experiments 50( The Fattening Experiment 51i SECOND EXPERIMENT 5.S1 Composition of the Control Pigs 5ol The Maintenance Experiments 53' The Fattening Experiment 55^ A Comparison of 12 25- Pound Pigs of Both Experiments 5Gf Measurement of Type 56? Digestibility and Metabolizable Knei-gy of the Fattening Ration 57; Relation of Feed Consumed Above Maintenanct' to (iross Knergy of Gains 57" NUTRIENT REQUIREMENTS OF PIGS 5s Relation of Weight to Age 5s: Relation of Chemical Composition to Weight 58- Relation Between Age and Maintenance Requirements 58! Nutrient Requirements of Pigs of Different Weight 59: STMMAHV AND CONCLUSIONS . . 591 series of bulletins on SWIXE TYPE STUDIES includes the following: I. TYPE IN SWINE AS RELATED TO RATE AND ECON- OMY OF GAIN (Bnllftin !.'!>. II. TYPE IN SWINE AS RELATED TO QUALITY OF PORK (Bulletin 322). III. THE ENERGY AND PROTEIN REQUIREMENTS OF GROWING SWINE AND THE UTILIZATION OF FEED ENERGY IN GROWTH (Bulletin THE ENERGY AM) PROTEIN REQUIREMENTS OF GROWING SWINE AM) THE UTILIZATION OF FEED ENERGY IN GROWTH By II. II. MITCHELL AND T. S. HAMILTON* A series of investigations relating to the general question of the comparative value of different types of Poland China pigs for market production was started by the Animal Husbandry Department of the University of Illinois in the summer of 1922. The division of Animal Nutrition cooperated in this work during the first two years to the extent of analyzing the carcasses of the pigs individually, analyzing the feeds, supervising the maintenance feeding trials and, in the second year's work, determining the digestibility and metabolizable energy of the ration fed, both at the maintenance level and at the fattening level of feeding. The large amount of experimental data thus accumulated : a significance far more general than the comparison of the different types of pigs used in the work, and in this bulletin the bearing of these data upon the general problems of swine nutrition will be considered. GENERAL PLAN OF THE EXPERIMENTS The types of Poland China pigs analyzed in the experiments of HH'2-23 and 1923-24 may be described as follov. Typt A. V< rji riniffn. The Very f'huffy pigs were extremely short-bodied, low-set, thick animals capable of being fattened at an early age. tho never attaining an extremely large size. Perfection in this type was exemplified by the famous old boar. Chief Perfec- tion 2d. The popularity of the type covered the period from about 1895 to 1908. Type B, Chuff y. The Chuff y pigs were the same general type of animals as the Very Chuffy, tho they were much less extreme and showed considerably more size and growth! ; Type C, Intcnnf <>F OKOXVING SWINK 495 five dt' tin- fattening plus of each type at a weight of IT.") pounds, five more at ;i weight of '2'2~> pounds, and five more at a weight of 275 pounds. while five plus of each type were to be used at a weight of 225 pounds in a maintenance feeding period. However, in the ex- periment of 1923-24 there was considerable mortality among the ex- perimental pigs, due to pneumonia, and the numbers slaughtered at the different weights were necessarily somewhat reduced. In the experiment of 1922-23 the ration consisted of shelled corn. wheat middlings, and tankage in proportions varying with the growth of the plus. In the following experiment a small amount of alfalfa meal was introduced into the ration. Only in the experiment of 1 M23-24 were the digestibility and metaboli/ablc energy of the ration determined. Because of several important differences in the details of the two experiments, they will be considered at length separately. FIRST EXPERIMENT The large majority of the pigs used in the first experiment (1922-23) were farrowed in March: a few were farrowed in late February, and a few in early April. The experiment started July 8, so that the average initial age of the pigs was approximately 3.."i months. COMPOSITION OF THE CONTROL PIGS Five pigs from each of the three types, B, 0. and D (Ohuffy, Inter- mediate, and Rangy ) . were slaughtered at the beginning of the ex- periment at an average live weight of 29. T kilograms (65.4 pounds). The carcasses were dressed in the ordinary manner and divided into symmetrical halves; one of the halves was then separated with the knife into bone, lean, visible fat, and skin. The bone. lean, and fat of each pig were analyzed separately, but the skin, after being weighed, .; round and composited for analysis for all 15 pigs. Composite samples were also prepared for the blood and for the brain. The thoracic and abdominal viscera of each pig constituted another chemical sample, which included edible as well as inedible organs and the abdominal fats. The tail was also added to this sample. For convenience in the preparation for analysis, the ears and snout were weighed separately for each pig and composited for analysis (for all pigs of the same type) ; the wet hair as removed after scalding and the toenails of all pigs were composited for analysis. The contents of the intestinal tract unfortunately were not weighed for any of the pigs slaughtered in the first experiment. The weights of these various parts of the can-ass for each of the 15 pigs are given in Table 1, grouped according to type. The most noticeable features of this table relative to type differences are the 496 BULLETIN No. 323 [May, TABLE 1. -WEIGHTS OF SAMPLES ANALYZED FROM THE CONTROL PIGS: FIR&T EXPERIMENT Pig No. and sex 1 Live weight Fat Lean Bone Skin Offal and tail Blood Brain Ears and snout Hair (wet) and toes Type B Chuffy Ib . ... kg*. 24.04 grams 5 797 grains 5 720 grams 3 111 grams 1 044 grams 3 345 grams 975 grams 57 grams 212 grams 311 2b 30.84 6 225 7 896 3 848 1 345 4 039 907 71 269 467 3b 28.12 5 169 8 308 3 558 1 414 4 082 1 270 85 241 368 4a 25.40 4 388 7 445 3 110 1 189 2 806 703 57 241 283 5b 31.29 5 454 9 355 3 525 1 727 3 926 1 134 66 269 396 Average. . . . 27.94 5 407 7 745 3 430 1 344 3 640 997 67 246 365 Type C Intermediate 6b 27.66 3 922 8 701 3 851 1 216 3 742 1 338 71 212 396 7b 33 . 1 1 6 662 10 120 3 952 1 419 4 422 1 156 85 269 425 8b 27 21 3 995 7 869 3 697 1 371 3 883 929 57 241 340 9s 29.93 5 026 9 480 3 979 1 264 3 975 975 71 269 396 10b 32.20 5 699 10 151 4 517 1 343 4 592 1 202 57 354 425 Average. .'. . 30.02 5 061 9 264 3 999 1 322 4 123 1 120 68 269 396 Type D Rangy lib 30.39 4 289 8 948 4 820 1 705 4 224 1 179 64 326 340 12b 29 93 3 820 10 378 4 294 1 460 4 110 1 088 71 241 382 13b 37.64 6 895 11 175 5 059 2 002 4 521 1 723 71 340 496 14b 25.85 2 671 6 906 3 983 1 323 3 657 907 57 255 311 15b 32.65 4 326 10 683 4 610 1 691 4 181 1 383 71 283 3 8 Average 31.29 4 400 9 618 4 553 1 636 4 139 1 256 67 289 379 Aver, of all types 29.75 4 956 8 876 3 994 1 434 3 967 1 124 67 268 380 'b = barrow; s = sow. increasing averauv weights of lean, bone, and blood from the ('huffy. Intermediate, and Rangy animals, and the decreasing weights of fat. The percentage composition of the samples of lean, fat, and bone from the control pigs will be found in Tables 2, 3, and 4. In these tables and in all similar computations of this bulletin the crude protein is calculated by multiplying the nitrogen content by 6 instead of the conventional factor, 6.25. This factor was used in view of Armsby's conclusion 1 that the fat- and ash-free dry matter of animal carcasses contains an average of 16.64 percent of nitrogen. The melt- ing points of the fat in the fat samples were determined by the method of Wiley 2 with the results shown in Table 3. The energy value of 1 Armsby, H. P. The nutrition of faun animals, 204. Macmillan. 1917. 3 Sherman, H. C. Methods of organic analysis, 2d. ed., 192. Macmillan. 1912. 1929} ENERGY AND PROTEIN Run II;FM I:\TS OK CKOWINO 497 TABLE 2. CHEMICAL COMPOSITION OF SAMPLES OF Li:\\ MK.\T I-'KOM THE CONTROL Pi<;>: KIK^T KXI-KIMMKNT Pig No. Dry substance Crude proti-in (Nx6.0) Fat A.sh Gross energy per grain Type B Ch iffy prt. pi't. iii-l. 1 35.41 15.82 1.x. 32 36. tf, ll.C.:; 20.18 3 30.:K Guowixc; SWINE 4!>9 TABI.K 4. CHEMK AI. ( 'OMI-OSITIOX OK S\MI-LE< OK MONK FROM THK CONTROL : FlUST EXPERIMENT Pig No. Dry substance Crude protein ,.0) Gross energy per grain Typo B Chuffy pet. pet. pet. ,,cl. sm. 1 17. I'd 16.36 17 57 1 3 . 4 1 14.44 14.77 12.40 14.88 16.74 A\ i - 47.56 17.55 14.63 13.75 2 474 Type C Intermediate 16.86 13.94 2 198 : 16.98 14.76 12.96 8 4:5 74 13.11 12.09 9 46.00 13.04 14.41 2 186 10 ... Hi 74 13.03 12.24 2 288 Average 45.46 17.08 13.77 13.13 2 254 Type D Rangy 11 15.30 1 II . !4 2 475 12 13 . . 16.14 17.16 14.61 15.37 11.50 13.63 2 586 14 15 4.") 42 17.10 1 7 . 52 16.64 13.10 11 . 07 12. 14 2 168 2 380 Average of all types 17.09 14.43 13.01 2 369 calories per rrram. If it may be assumed that these pi^s had the same average "fill'' as the control piyrs of the experiment of 1923-24. that is. 7.49 percent, the average composition of these pigs on the empty- weight basis would be as follows : dry matter, 36.75 percent : crude protein, 12.55 percent: fat. 20.20 percent: ash. 2.46 percent: and 38 energy, 2. '194 small calories per gram. TABLE o. AVERAGE CHEMICAL COMPOSITION OF BLOOD, SKIN. AND BRAINS OF THE CONTROL PIGS: FIRST EXPERIMENT Sample Dry substance Crude protein ..0) Gross energy per gram Blood . . pel. K> 79 pet. 14 88 pet. .11 pet. 1.30 1 069 Skin 48.00 21.00 .48 Brains 30.46 9.42 9.09 1.58 1 633 498 BULLETIN No. 323 TABLE 3. -CHEMICAL COMPOSITION OF SAMPLES OF FAT FROM THE CONTROL PIGS: 1'lH^T KXPERIMENT Pig No. Dry substanoe Crude protein (Xx6.0) Pal Ash Gross energy per gram Melting point Type B Chuffy 1 pet. 79.06 78.69 75.18 70.41 70.47 74 . 70 pet. 4.87 5.82 7.38 6.78 6.12 pet. 67.19 68.04 68.56 60.81 65.47 pet. .32 .32 .32 .32 .32 .32 sm. cals. 6 873 6 762 6 699 6 370 6 286 6 598 33.0 34.3 31.6 35.0 36.0 34.0 2 3. . . 4 5 Average Type C Intermediate 6 69 81 '' 7l' 60.79 .38 6 188 39 7 71 92 6 36 <<7 "7 .38 6 297 41 8 69.18 7 44 62.83 .38 6 065 36.0 9. 70.82 6.72 112 "it .38 6 263 39 10 71.19 6.96 62.60 .38 6 076 35.5 Average 71.18 6.84 63.21 .38 6 178 38.1 Type D Rangy 11. 66 43 7 lil! :,7 -':> .39 5 802 31.1 12 61.81 8.46 52.84 .39 5 379 37.0 13 70.51 .39 6 005 37 . 7 14. . C3 12 8 64 51.40 .39 5 481 31.2 15 65.78 8.22 57.29 .39 5 609 35.0 65.53 8.04 56.30 .39 5 656 34.4 Average of all types 70.49 7.00 61.66 .36 6 144 * 35.5 pig, as noted in Table 1, was 380 grams. Since this sample contained 28.16 percent of dry matter, the average weight of dry hair and toe- nails was 107 grams. This dry matter contained 81.2 percent of protein (X x 6.0) . and 4.0 percent of ash, and possessed a gross energy- content of 5.50 calories per gram. The nutrients found in the various samples for each pig were sum- mated and expressed as percentages of the live weight of the pig. These percentages were used in computing the initial composition of the fat pigs, an essential step in the estimation of the composition of the gains made. They represent, therefore, the most significant results of the analyses of the control pigs and are summarized in Table 6. The average composition of these 65-pound pigs was 34.00 percent dry matter, 11.61 percent crude protein (Xx6.0), 18.69 percent fat, and 2.28 percent ash ; the average gross energy content was 2,474 small 1929] KM:KI;Y AMI I'KOTKIN RKQI:II:KMK.\T> y GROWING SWINE 41)9 TABLE 4. CHEMICAL COMPOSITION OF SAMPLES UK HUNK FKOM THK CONTROL I'n;>: FIIOT KXPKKIMKNT Pig No. Dry Crude protein '..0) F:it Ash Gross energy per gram Type B Chuffy ]>ft. pet. i>ct. I i- 17.20 1C,.. 'ii; 50.3.1 17.. -.7 17.58 14. H t: 18.66 12.40 4:-! . 7.'. Average 47.56 17.55 14.63 Type C Intermediate 46.28 16.86 14.93 7 46.73 16.98 14.76 8 4.S.71 13.11 9 4(1.00 17.28 13.04 10 If,. 74 13.03 Average 45.46 17.08 13.77 Type D Rangy 11 ! 15.30 12 44.20 16.14 14.61 13 48.28 17.16 15.37 14 43.70 17.10 14. til' 15 45.86 17.52 13.10 Average J.1.42 14. S7 pet. 12.95 13.41 14.77 12.72 2 117 2 378 L' 474 13.94 12.96 12.09 14.41 1 2 . 24 13.13 2 198 2 381 2 218 2 186 2 288 10.94 11.50 13.63 11.07 13.58 12.14 2 47.5 2 586 2 168 2 380 Average of all types 16.15 17.09 14.43 13.01 2 369 calories per gram. If it may be assumed that these pi^s had the same average "fill" as the control pigs of the experiment of 1923-24, that is. 7.4!) percent, the average composition of these pigs on the empty- weight basis would be as follows: dry matter. ?>f>.~?> percent: crude protein. 12.5.") percent: fat. 20.20 percent: ash. 2.4(5 percent: and -- ; energy, 2.694 small calories per gram. TABLE o.- CHEMICAL COMPOSITION OF BLOOD, SKIN, AND BRAINS OF THE CONTROL PIGS: FIRST EXPERIMENT Sample Dry substance Crude protein (NxC.O) Fat Ash Gross energy per gram Blood. Skin. . . Brains. 16.79 48.00 20.46 pet. 14.88 21.00 9.42 pet. .11 25.70 9.09 pet. 1 . 30 .48 1.58 "rn. cal.i. 1 069 3 565 1 633 500 BULLETIN No. 323 [May, TABLE 6. CHEMICAL COMPOSITION OF ENTIRE CARCASSES OF THE CONTROL PIGS: FIRST EXPERIMENT Pig Xo. Dry substance Crude protein Xxtj.0) Fat Ash Gross energy per gram Type B Chuffy pet. pet. pet. 1 40.47 10.84 25.01 2 38.50 10.05 23.55 3 36.36 11.94 21.31 4 33.24 11.17 18.43 5 33.16 11.46 18.93 Average 36.35 11.09 21.45 Type C Intermediate 6 32 12.01 17.03 7 37.39 11.36 22.69 8 31.68 11.65 17.06 9 33.89 11.80 18.49 10 34.86 12.01 18.79 Average 34.16 11.77 18.81 Type D Rangy 11 32.68 11.84 16.98 12 30.86 12.49 14.74 13 34.99 11.69 19.56 14 27.61 11.39 12.59 15 31.31 12.42 15.15 Average... 31.49 11.97 15.80 pet. 2.19 2.15 2.45 2.53 1.97 2.26 sm. cols. 3 080 2 844 2 720 2 482 2 537 2 733 2.52 2.11 2.19 2.48 2.29 2.32 2 343 2 727 2 271 2 485 2 522 2 470 2.28 2.28 2.39 2.21 2.51 2.33 2 328 2 143 2 540 1 894 2 183 2 218 Average of all types 34.00 11.61 2.28 2 474 THE MAINTENANCE EXPERIMENTS Amounts of Feed and Energy Required for Constant Weight. At the beginning of the experiment five pigs from each of the three types were put upon a maintenance experiment in order to determine the amounts of the ration fed at the beginning of the experiment re- quired to maintain constant weight. Again, at the end of the experi- ment, when the fat pigs had reached a weight of approximately 22.") pounds, five pigs from each type were subjected to a maintenance experiment, the ration being fed to the fat pigs at that time being used in this case. The ration used for the fattening pigs in this experiment consisted of shelled corn, wheat middlings, and tankage : the proportions fed varied as the experiment progressed, the proportion of corn increasing and the proportions of middlings and tankage decreasing. For the entire fattening period the average ration contained 76 percent of 1929] ENERGY AND PROTEIN REQUIREMENTS OF GROWING SWINE 501 TABLE 7. RESULTS OF MAINTENANCE EXPERIMENT ON THE YOUNG PIGS: FIRST EXPERIMENT Pig No. and sex 1 Initial weight Mainte- nance weight Average daily feed Average daily feed per 100 pounds live weight Corn Tankage and mid- lings* Total Weight ratio Surface ratio Type B Chuffy lib Ibs. 51 Ibs. 51 Ibs. .33 Ibs. .16 Ibs. .49 Ibs. .97 Ibs. .78 12b 40 43 .37 .19 .56 1.31 .99 13b 47 52 .31 .15 .46 .89 .72 14b 64 62 .55 .28 .84 1.36 .73 15b 52 52 .36 .16 .52 1.01 .81 Average 51 52 .39 .19 .57 1.11 .81 Type C Intermediate 6b 46 49 .31 . 14 .45 .93 .73 7b 50 54 .31 .15 .46 .85 .70 8b 46 52 .36 .19 .55 1.05 .84 9b 47 51 .32 .16 .48 .94 lOb 44 51 .35 .17 .52 1.02 .82 Average 46 51 .33 .16 .49 .96 .77 Type D Rangy lb . 47 51 .32 .16 .48 .95 .76 2b 44 48 .37 .19 .55 1.16 .90 3b 44 51 .32 .16 .48 .96 .76 4s 49 53 .36 .19 . 55 1.04 .84 5b 48 50 .32 .16 .48 .98 .77 Average 46 51 .34 .17 .51 1.02 .81 Average of all types. . 47.7 51.3 .353 .173 .523 1.03 .797 'b = barrow; s = sow. The mixture used was 2 parts middlings to 1 part tankage. corn. 16 percent of middlings, and 8 percent of tankage. During the maintenance experiment on the young pigs the average ration con- tained 67 percent of corn, 22 percent of middlings, and 11 percent of tankage, while in the maintenance experiment on the fat pigs the tankage was eliminated and the corn and middlings made up 81 and 19 percent respectively of the average ration fed. The maintenance feeding continued for 16 to 17 weeks. "With the fat pigs a period of at least 8 weeks was obtained in which the pigs were at constant weight on constant feed. In this test, after a sharp initial drop in weight during the first week of reduced feed, the weights of the pigs were maintained at a practically constant level 502 BULLETIN- Xo. 323 TABLE 8. RESULTS OF MAINTENANCE EXPERIMENT ox THE FAT PIGS: FIRST EXPERIMENT Pig Xo. and sex Initial weight Mainte- nance weight Average daily feed Average daily feed per 100 pounds live weight Corn Middlings Total Weight ratio Surface ratio Type BC huffy Ibs. 223 /6s. 206 tbs. 2.06 Ibs. .50 Ibs. 2.56 Ibs. 1.24 Ibs. 1.58 lib 227 213 1 56 .38 1.94 .91 1 17 13s 225 204 1 63 .38 2 01 98 1 25 14s 232 229 1.44 .31 1.75 .76 1.01 20b 227 216 1.56 .38 1.94 .90 1.16 Average 227 214 1.65 .39 2.04 .96 1.23 Type C Intermediate Is 227 221 1.50 .38 1.88 85 1.11 3b 222 219 1.44 .31 1.75 .80 1.04 14s 227 219 1.75 .44 2.19 1.00 1.30 171> . . ... 229 217 1.81 .44 2.25 1.04 1.34 20s. . 225 219 1.56 .38 1.94 .89 1.15 Average 226 219 1.61 .39 2.00 .92 1.19 Type D Rangy 8b 224 209 1.94 .43 2.37 1.13 .45 lOb 224 217 1.94 .43 2.37 1.09 .41 lib 225 2.06 .50 2.56 1.26 .59 13b 220 213 1.63 .38 2.01 .94 .21 17b 224 205 1.81 .43 2.24 1.09 .39 Average . . . . 223 210 1.88 .43 2.31 1.10 1.41 Average of all types. . 225.3 214.3 1.71 .403 2.12 .99 1.28 for the remainder of the period. With the young pigs, altho the original weight was generally increased slightly in the first few weeks, it was found necessary to reduce the feed gradually over a much longer period than in the second maintenance trial. As a result, a period of only 5 weeks of constant weight on constant feed was obtained. The experiment could not be extended further because of the approach of cold weather, which tended to reduce the weights of the pigs on amounts of feed that had proved adequate for maintenance. The average data for these two maintenance trials are given in Tables 7 and 8. The average analyses of the feeds used are given in Table 9. The corn used in the maintenance experiment on the young pigs is represented mainly by the sample taken from July 1 to September 19, 1929} KNKKGY AND PROTEIN REgriuKMK.vrs OK <;I;O\VIM; s \vi\i-: 503 TABLE 9. CHEMICAL COMPOSITION OF FKKDS I'SKD: FIRST KXI>KJUMI:\T Feed Dry N-free extract Crude protein (Nx6.25) Ash Crude fiber I :it Gross energy per grain Yellow corn: July 1 to Sept 19 pc*. 90 06 pet. 72 63 pet. 9.62 pet. 1.46 pet. 2 (1!) pet. 4.26 sm. cats. 4 001 Sept 19 to end of ex- V.I 1 1 71 dl 9.46 l . :) L>. 11' 1.29 4 041 Average 80.74 72. I'd 9.54 1.38 2.26 4.28 4 021 Tankage 91.61 5.21 57.50 19.26 2.00 7.64 middlings 88.94 65.06 16.17 2.44 2.51 2.76 4 002 while that used in the maintenance experiment on the fat pigs is represented entirely by the second sample taken. The two samples of corn were approximately the same in composition. The maintenance energy requirements have been expressed as weights of feed required per day per 100 pounds live weight. In reducing to this basis the actual experimental results obtained, two methods have been used, the one involving the ratio of the live weight of the pig to 100 pounds, and the other the ratio of the two-thirds power of these weights. The latter ratio is approximately the same as the ratio of the surface area of the pigs to the surface area of a 100-pound pig. The method involving the surface ratio is apparently the preferable one for the basal metabolism of animals, but in live- weight maintenance, such as obtained in this experiment, the energy requirements of the pigs relate not only to the basal metabolism but also to an unknown amount of muscular metabolism incidental to the muscular activity in the feed lots. It has been well established that the amount of energy consumed in locomotion, either along a level or up an incline, is proportional to the body weight ; it bears no evi- dent direct relation to the basal metabolism or to the body surface of the animal. Hence, in so far as the requirement of energy by these pigs relates to the basal metabolism the surface ratio is preferable in equating the experimental results for differences in size, but in so far as the requirement relates to the activity of the voluntary muscles the weight ratio is preferable. There seems to be no way of deciding which method of equating for differences in size is preferable except by consulting the figures. It will be noted that for the two groups of pigs the maintenance re- quirements computed from the weight ratio are closely the same, while those computed from the surface ratio are quite dissimilar. From the weight ratio the average requirement of the young pigs was 1.03 pounds of feed per day per 100 pounds live weight and for the fat 504 BULLETIN Xo. ;\-2: [May, TABLE 10. WEIGHTS OF SAMPLES ANALYZED FROM THE YOUNG MAINTENANCE PIGS: FIRST EXPERIMENT Pig Xo. and sex 1 Live weight Boneless meat Bone Skin Offal Blood Brain Ears, snout + tail Type B Chuffy lib kgs. 21.77 grams 9 944 grams 3 695 grams 1 481 grams 2 900 grams 510 grams 83 grams 204 12b 13b 18.28 22.08 8 181 9 792 2 937 3 862 1 484 1 553 2 400 2 629 624 624 105 81 219 285 14b 27.75 13 510 4 469 1 614 3 435 851 84 368 15b 21.43 7 975 3 853 1 630 3 139 851 97 270 Average. . . 22.26 9 880 3 763 1 552 2 901 692 90 269 Type C Intermediate 6b . 21.17 7 ,"42 4 369 . 1 955 2 700 737 77 223 7b . 22.93 10 634 4 247 1 704 2 850 713 88 257 8s 22.56 10 321 4 286 1 832 2 655 624 85 310 9b 22.08 10 640 3 585 1 522 2 635 936 85 206 10b 21.85 9 101 3 854 1 331 2 800 879 80 242 Average. . . 22.12 9 688 4 068 1 669 2 728 778 83 248 Type D Rangy Ib 21.88 9 425 3 607 1 868 2 606 709 75 250 2b 20.69 8 634 4 124 1 538 2 930 539 90 235 3b 22.31 9 115 4 213 1 749 2 870 539 95 183 4s 9 790 4 493 1 758 3 102 765 80 226 5b . 21.31 9 114 4 212 1 506 2 755 794 91 285 Average. . . 21.78 9 216 4 130 1 684 2 853 669 86 240 ] b = barrow; s = sow. 'Sample lost; average of all results substituted. pigs .99 pound. From the surface ratio these average requirements were, respectively, .80 pound and 1.28 pounds. Changes in Composition of Young Maintenance Pigs. The de- termination of the maintenance requirements of animals by feeding experiments involving only live-weight determinations is known to be subject to error since the maintenance of live weight does not neces- sarily indicate the existence of a condition of nutritive equilibrium. This is especially true of young animals, in which continued subsist- ence on a ration inadequate for growth will nevertheless not entirely inhibit growth. In such animals body weight may be maintained con- stant, in spite of an increase in water, protein, and mineral matter, by a corresponding reduction in the content of fat, resulting in a con- siderable reduction in the energy content of the body. Thus live- weight maintenance trials on immature animals will always under- 19X9} ENERGY AND PROTEIN REQUIREMENTS OF GROWING SWINE 505 TABLE 11. CHEMICAL COMPOSITION OF BONELESS MEAT FROM THE YOCN<; MAINTENANCE PIGS: FIRST EXPERIMENT Do- substance Crude protein ..0) Fat Ash rc*s energy per gnun Type B Chuffy pet. pet. pet. II 39.16 13.80 22.99 31.60 15.12 16.42 13 27.66 16.14 10.24 14 37.00 14.52 20.55 15 2' ' 17. 04 7.11 Average 32.23 15.32 15.4':. Type C Intermediate 6 J3.65 16.08 5.43 29.72 15.00 13.08 8 25.68 16.20 8.27 9 33.11 16.50 14.58 10 JS.29 16.56 10.25 Average 2S.07 1607 10.32 Type D Rangy 1 27.43 - -. 7.01 32.13 16.26 13.12 3 30.86 16.62 11.68 4 30.09 15.42 12.67 5 32.66 14.04 16.78 Average 3O.63 15.91 12.25 pet. n .83 .86 .83 .90 rm. colt. 2 992 2 231 1 P*4 2 909 1 726 .85 .84 .88 .88 1 367 2 073 1 777 2 3SO 2 018 1 923 .84 .81 n .81 ' 2 383 2 141 2 113 2 396 2 150 Average of all types 30.31 ' -' i2.es 2 154 estimate the energy requirement of maintenance, and the more imma- ture the animal the greater will be this underestimation. Because of these well-known facts the pigs used in the maintenance trials in this experiment were slaughtered and analyzed at the end of the feeding period. By comparing the composition of the young main- tenance pigs with that of the control pigs slaughtered at the beginning of the experiment, an estimate could be made of the change in com- position during the maintenance feeding period. On such an estimate could be based a more or less satisfactory correction of the daily feed consumption required for the maintenance of weight, and thus the daily feed consumption required for the maintenance of energy equilibrium could be obtained. The sampling and analysis of the young maintenance pigs was car- ried out in a manner essentially the same as that of the control pigs except that the lean and the fat were analyzed tqgether. The weights of samples from these pigs are given in Table 10. and the chemical 506 BULLETIN \ TABLE 12. CHEMICAL COMPOSITION OF BOXES OF THE Yorxc MAINTENANCE PIGS: FIRST EXPERIMENT Pig No. Do- substance ! Crude protein i (.XX6.0) Fr.t Ash Type B Chuffy ] prt. 51.00 ... 51.70 prf. 17.34 17.28 prf. 13.73 prf. 16.44 16.97 ftn. eaLs. 2 469 ! . 13 - - ' 11.66 - 52 2 141 ... 54.06 16.92 17.30 17.47 2 619 ' -age ...1 46.90 50. 4S - 17. 23 10.65 13.64 17 22 17.32 1 999 2 370 Type C Intermediate 6 - I 17.16 9.01 15.45 1 989 - 16.80 14.52 16.00 2 335 - 17.40 10.94 15.70 2 072 ... 18.00 16.13 19.29 2 543 10 51.11 - n 12.00 19.32 2 171 Average 49.29 17.62 12.52 17.15 2 222 Type D Rangy 1.. . 46.61 1 10.20 16.60 2 044 47 60 16.50 13.89 15.55 2 318 3 45.30 16.26 10. 40 15.49 1 999 17 ~ . 13.21 15.79 2 377 " 15.66 14.58 15.74 2 362 16.55 _ -' 15.83 2 220 Average of all types 49.01 17.13 2 271 composition of the boneless meat and of the composite bones in Tables 11 and 12 respectively. The blood, skin, and brain were weighed separately for each pig but were composited for analysis. The results of these analyses will be found in Table 13. The hair and toenails from all pigs were collected and analyzed. It was estimated that each pig contributed to this sample 164 grams of dry matter containing TABLE 13. AVERAGE CHEMICAL COMPOSITION OF BLOOD. SKIN. AND BRAINS OF THE YOUNG MAINTENANCE PIGS: FIRST EXPERIMENT - Dry substance Crude protein Xx6.0) Fat Ash Gross energy per gram prf. prf. prf. prf. em. cols. Blood 20.12 15.66 .06 1.56 1 283 Skin 3>7 36 22 56 14 11 56 2 491 Braics 21.72 9.90 9.24 1.33 1 481 19*9] ENERGY AXD PROTEIX RBQI.IKEMEXT& or Geuwixc SWTXE 107 TABLE 14. CHEMICAL CoMpasmox or EXTIHE CARCASSES OF THE Yorxc MAJXTEXAXCE PIGS: FIRST EXPERIMENT Pfc Drr ..-: .* '^ J '-:r- -* c~i."- Type B Omffijr '' ret. fO. ^* D*L 11.... 33.77 13.58 :-> -y 3.38 _' Z4> - -V> *> 14.65 33 i* 3.38 3 >*-:i; 27. 7O 14.72 i 30 1. 81 3 -:-.- : ; 33.55 3i >-> 3.45 -' _S4 ' 14.43 6.41 3.71 3 *> \TCTaW 3O.25 14. 3S 11.29 3.. r . 3 :--. 3 71 i Si'i'5* 3 . 28 29 14 43 8 5 W 1 711 4 : - -*. t'4 - | 88.5 percent of crude protein (Xx6.0), 5:2 percent of ash, and 902 calories of gross energy. The analyses of the offal sample, eonsistinsr mainly of the visceral organs and of the ears, snout, and tail, will not be reported since they possess no particular significance in themselves. From the weights of samples and their percentage composition the total amounts of the different chemical constituents in the carcasses of the pigs were determined, and from these amounts and the live weights of the pigs the percentage composition of the entire carcass (live weight), exclusive of the contents of the alimentary tract, was determined- The results 01 these calculations are given in Table 14. The average analyses for all types of pigs in the maintenance and control groups of the boneless meat (lean plus fat), bone, offal, and entire carcass have been summarized for comparison in Table 15. Evidently during the period of maintenance feeding the growth of the maintenance pigs was not suppressed alt ho their food consumption I HB . - -:- -:- -. XI I -s* I -.. : . : - i:^ CT TTtf- ifSl . : : Qnrih 4* 40 ~" ri- .*/." . HJB a..- -. .*i * 7, [ eT -..u. s. .V tmt 7i JH .- ;-- __ , , _ -^__ -i^.* * -_ .- * 1^.12. 4J. '3 ^t..* HE -^. <2. -tf..^. 3K^V ,^ Q iur j^-ii "iH^'Tiii.iein' ^rf t. ;r ~ii^ -..-;_.- un.:t:Ti~cn : M -<.::-"-- ~' :i '-ic ill.. 'ii.iuii ; : - _L vit-u 7 ir i: ^ n t ;.ii.~*- 510 BULLETIN No. 323 [May, TABLE 17. -COMPARISON OF PERCENTAGE COMPOSITION OF DRESSED CARCASSES OF THE 225-PouND FAT PIGS AND THE 225-PouND MAINTENANCE PIGS: FIRST EXPERIMENT Group of pigs Dry substance Crude protein (XxG.O) Fat Ash Gross energy per gram Carcass composite pet. pet. pet. pet. sm. culs. Chuffy type Maintenance pi:. 1 51.68 14.79 33.14 3.80 3 932 Fat pigs 63.31 13.00 45. 12 2.73 5 060 Intermediate type Maintenance pi^ 59.42 12.28 43.11 3 . 25 4 797 Fat pigs 64.30 13.34 46.27 2.71 5 108 Rangy type Maintenance pigs. . . . 54.29 13.85 36.09 3.66 4 137 Fat pigs 62.19 13.59 44.44 2.93 4 960 Offal Chuffy type Maintenance pigs. . . . 29.00 13.58 12.60 1.15 1 996 Fat pigs 27.79 11.83 12.83 .82 1 960 Intermediate type Maintenance pigs. . . . 32.52 13.00 17.28 1.09 2 385 Fat pigs 27.90 11.79 12.71') .81 1 991 Rangy type Maintenance pigs. . . . 30.78 14.14 13.49 1.10 2 110 Fat pigs 27.06 12.18 11.51 .86 1 899 The data are not at hand for an estimate of the complete composi- tion of the entire carcasses of the 'JiM-pouml maintenance pigs. How- ever, satisfactory estimates of their total gross energy values will be found in Table 19. Estimates of Feed Required for Maintenance. There are rather serious difficulties in the way of any method of correcting the food intake records of the two groups of maintenance pigs in order to get a satisfactory estimate of the amounts of food required to maintain a condition of energy equilibrium. The method we have adopted yields the results given in Tables 18 and 19. Obviously in using the results of the slaughter tests, it is necessary to use the total feed consumption of the maintenance period from the first day of feeding to the day of slaughter rather than the feed con- sumption found to be best adapted to the maintenance of constant weight, as used in Tables 7 and 8. The estimates of the original energy content of the pigs in each type are based upon the average energy content of the control pigs of that type. The final energy contents ENERGY AND PROTEIN REQUIREMENTS OK O ROWING SWINE r.ll J_ > t r ^ ~ - = - '- f i t 5 i S : - 3 2 8 2 s 00 ^ CC o f ~ ~ ~i -" ?l -i 1C = = C-. ^ :e x i- * ce 00 N '-. - ~ ~ ' < r * ~ ' O c 5 *i / r -i f: ^ i- t- >-. a ~ aa ^< C3 S~ O -* L e- IN - - - 3*225 S ,0 . co c | KSSSK "3 C ~ ! t>. C I- 'r rl X ^ !r !N g H5 O -H 00 CO h- E O> CO C =: M X -^ c b- - - - - M ~ " ."* ?) re f~ ~. " _ :: :: - i a - r r -M o oo co -^ re -r n w a -i ~> s - re ^ co O -. ~ n re ?! ~) f ~- t^. t^ ~ JS 55 55 5 -. z -. -. q -C t" -^ -- r- ~ t~ '". s. ~ t~ - 00 S "S : : : : : : : : : : : : : a : : : : : '.'.'.'. o | -. - ^ J - ^ 0> 00 b = t) * CO CS rH < 512 BULLETIN No. 323 a S ej o 1 a OD O lO t^ ^f 11? >~ -0 CN ^ f CO CN CO 15 < CN t>- iO H J, tn " Pip -tf W'U *. > ,J3 O Q) >i;~ 5$ .S CN CO C! 1 CM CO O !N CN IN O 00 O Ol 00 O5 O O O O> O "-" "- 1 K- o o co C<5 CN CD O *!< CM co ^ O Q) ^ , a * -2 >> 1 .5 "03 . 5 o r^ a co CN to CO CO I s * ^ CO CO -. CO CO O i U5 -H o co co o -H "5 CO ^< CO CO i-c t^ to ^ i Ci CO 5 M ~ CO CN CN CN CN (N IN i-i CN CN CN CN CN CN CO CN IN CN ?t 1 1 O W 00 O CO CO Tf< ;O r^ ^ CO Ci -^ CO CO CO CN CO c co M co C^ CN CN CN CN 00 t^ O CO CN o co co co CN CN * CN U5 h C .S a .0 & 5 F> 3 .g ft H ^- CO O O Cl ^^ .C i-i CN -. CO 1O H5 O t^ CO CN CN O C5 -< CO CO iO -H O 4 i M M 1111 * fe 1 ~ '. -^ -N CO C '-T "^ C3 1O t* 10 lO O 00 00 i-i CN CN 1 ~ 1 1 CO CO ! CO O IN IN C5 C5 1 Z c z; a >. ta 3 s ^ M> co o co oo X 00 lO CD T< 00 ~ CM CN CN CN CN ntiTineiliut CO CO CO 10 C7S 115 iC CN N CO IN CN (N C^ C^ 1 s T 5 Tj< T< CN CO O f- CO * C5 CN CN CO W * S ^ O *o 2; 5n >-) C3 xj q s. >, H E lO O l t U3 h- fc CN t- CO b- 05 Type C I O I-H lO IN }< CN 7 ~ 1 1 Q o O. H O - CO 00 O C CO CO CN CN CO o 3 -3 fcg 2 - s c a S 1O b- O C75 IN O t- ^- CO O T)< CO CN _i o) co co co co co O CO -f 00 * N O CS . CO iO O ^ CD 1(5 co co t*- cTi t> co CO CO CN CO CN CO co co 5 -3 >> c < s* & Js i '3 S e S O i^ co co t-- r^ K -H O 00 O 00 (N * CO O c Avera co -H co * o i-H rt rl CN " S 5 8* oo o i co t^ 1929] ENERGY AND PROTEIN REQUIREMENTS OF GROWING S\\IM. 513 of the pigs were directly determined as explained above. The esti- mated losses (or gains) in energy during the maintenance period are converted into terms of feed on the somewhat dubious assumption thai the metabolizable energy of the rations consumed, as estimated from results obtained in the next year's experiment, would be ulilixed to the extent of 100 percent in preventing a loss in body energy. Some estimate of this sort is required in order to make the correc- tion desired, and the selection of this ideal percentage was based upon the following considerations. Armsby 1 has estimated from available data that on fattening ralions swine utili/e over 78 percent of the metabolizable energy of their rations for maintenance and gain. Furthermore, Forbes. Fries. l>raman. and Kriss 2 have presented evi- dence to show that the metabolizable energy of the feed is utilized to a greater extent when fed at the maintenance or submaintenance level than when fed at the supermaintenance level. This is quite in agree- ment with the observation of Benedict and Benedict, 3 on human sub- jects, that the ingest ion of a small breakfast does not appreciably affect a basal metabolism determination that is made immediately afterward. The average estimate of the feed equivalent of the energy losses of the young maintenance pigs, according to the data obtained in this experiment (Tables 18 and 19), is equal to 14 percent of the total feed consumed and to 13.5 percent in the case of the 225-pound maintenance pigs. If it had been assumed that the metabolizable energy of the feed were only 78 percent net available for maintenance, instead of 100 percent, these percentage feed corrections would be in- creased to approximately 18. Evidently, therefore, any likely error in the feed correction for losses of body energy would not greatly affect the final estimate of the feed required for maintenance per 100 pounds live weight. Among the young maintenance pigs the energy content of the body decreased on the average 31 percent for the Chuffy type, 28 percent for the Intermediate type, and 16 percent for the Rangy type during the maintenance feeding period of 110 days. Among the 225-pound maintenance pigs the average percentage losses of body energy were 21, .5, and 15 respectively. The differences between the average type values are not readily explainable on the basis of differences in rate of growth or in the attainment of maturity. The consistently larger 1 Armsby, H. P. The nutrition of farm animals, 288. ' J Forbes. E. B., Fries, J. A., Braman, \V. W., and Kriss, M. Jour. Agr. Res. 33, 48.3. 1926. 3 Benedict, C. G., and Benedict, F. G. Boston Med. and Surg. Jour. 170, 849. 1923. 514 - percentage losses in body energy for the Chuffy type on at ration adequate for the maintenance of body weight may indicate a growth impulse for these pigs that is less readily inhibited by restrictions in the UMmd :: :<:: BonaoBed Before considering the final estimates of the amount of feed re- quired for maintenance, it is necessary to decide which method of reducing these amounts to 100 pounds of body weight is preferable "bai involving a ratio of weisihts or Thai involving a ratio of surfaces Hthirds powers of the weights]). The average estimates for all types by the weight ratio are 1.48 pounds of feed for the young pigs and 1-13 pounds for the older pigs; the estimates obtained by the surface ratio are 1-1 S pounds and 1.46 pounds respectively . In neither case do the values agree welL Using the weight ratio one would infer that the maintenance requirements are more intense (greater per unit of weight) for the young pigs than for the older pigs ; using the surface ratio, the opposite would be inferred. However, where differ- ences in maintenance requirements with age have been measured has been invariably found that, per unit of weight, the basal metabo- lism of the younger animal is greater than that of the older; and per unit of surface, where a difference exists, the younger animal again has a higher basal heat production. 1 The activity factor, which is of course involved in live-weight maintenance, is probably affected by age and also by seasonal factors 2 ; it is probably fair to presume 3 that, except for the very, young animal, increasing age is accompanied by decreasing spontaneous activity. Therefore, with respect to basal metabolism as well as spontaneous activity, one would expect a greater energy requirement per unit of size for the young animal than for the old. Since this relation is sboTTB by the estimates of maintenanc^e requirements per 100 pounds of body weight obtained by the weight ratio and is not shown by those obtained by the surface ratio, it is perhaps fair to assume that the former method is more satisfactory than the latter in varying such esaim&l-es for variation* in si&e and age. This is probably due to the fact that spontaneous activity plays a large part in determining the lor iive-^reiirhi maintenance. In assuming that the energy equivalent of this activity varies with surface rather than weight, the estimate for a 100-pound pig from results obtained on a 50-pound pig would be too low, while that made from results on a &oe$ mwt apply t tfce rerr jnmg aaimalK Tine new-born animal ha* ' ~Z.J'. >f trzL* : '' ?irfi.'ir. f C1 --- ~- ^'.. : '.^-~. 'lOttdbcodk, F. A. Amer. Joor. Fi^sidL 75, 205. 1925. BL P. Tfee mmtiftvm of fun aunafe, 307. 19X9] rl.'.'a.:T Oft ?i-."'?'iZ-"" Si^m-nt r."'?'= ". J BB0WHB ~'v-:_" " 1 r 225~pound pig: would be too high. In this connection it maty be re- called that Armsby,. Pries, and Braman" found that the basal of cattle of different weights, indirectly determined, was as weH eor- reJated with bod y weight as with body sour-foci?.. T;:- estimated r'-^i >-'-.-iirerr~^:.s r.r the young maintenance 7^~ per 100 pounds weight, it is interesting; to observe, are not distinctly different for the different types. For the older maintenance pigs, however, the Intermediate type appears to have a distinctly lower re- quirement of feed for energy equilibrium. 7 1-: I 7 -. 7 7 I 7 Composition of the Fat Pigs. When the 20 pigs off each type that were grown out and fattened reached a weight of approximately 225 ment; 15 in each type group were slaughtered and analyzed imme- diately and 5 were placed upon a maintenance feeding; test described in the preceding: section. The slaughter data and the weights of sample* taken for analysis for tine 45 fat pigs are given in Table 20; Tables 21. 22. and 23. Table 24 contains the analyses for the com- The average weight of brain for these 45 pigs was S9 grams, as compared with 67 grams for the 15 control pig&. line average weight of air-dried hair (plus toenails) was estimated to be 31$ grams. F:<:'- die ^e:z:i7s of s-i.rn.rlrs an-i .^ .ci.-e'ni^il ^^Z':^~'^-.'i percentage eompositson of the entire carcasses ((tree weight) was puted, with tine results givem in Table 25. Tioe weight of "1" in these carcasses was not determined. If it is assumed to be 5.6 percent of the fire weight, or the average of the 225-pound fat pigs of the of 7 of these 45 fat pigs, on the empty-weight basis, would be as foDows percent dry substance, lid percent crude protein X the same basis would be 4JL7 calories per gram,, or 1^9 therms per 10G pounds. Tie .iver-^z'T 7rr':irr.7.i.^ eompontiomi if the n::^ i~7-:r:.ir.7 chemi- cal s-in7-'.es md of the entire earean in ~'-~ ~^.'-*: 777.^ :: 7:i> ir-r summarized for comparison in Table 26. In spite of ttSne voy obrioms differences in tfee conformation of the three types of pigs and in their market condition at the time of slaughter., their chemical comnoration did not vary greatly. The Intermediate-type pigs proved to be anmr 1 A nn*6 T. H. P^ Fms, J. A, and Bnaauatm, W. W. Jonnr. Agr. Bcs. 43. 19119L 516 BULLETIN No. 323 [May, TABLE 20. WEIGHTS OF SAMPLES FROM THE FAT PIGS: FIRST EXPERIMENT Pig No. and sex 1 Live weight Total fat 1 Total lean Total bone Skin' Offal Blood Type B Chuffy lb kgs. 104.3 102.1 98.9 99.8 102.1 101.5 101.2 101.2 103.4 99.8 98.4 101.2 105.2 103.9 104.8 101.8 grams 29 600 31 645 29 718 24 729 31 591 30 361 26 806 32 093 29 737 27 624 27 127 30 157 30 376 32 315 34 015 29 860 grams 34 239 32 038 30 674 32 519 30 884 33 051 31 957 27 653 32 287 32 051 28 283 29 633 33 093 29 845 29 702 31 194 grams 8 741 8 842 9 656 9 406 9 072 7 902 8 846 8 654 8 399 8 348 8 987 8 395 9 393 8 406 8 953 8 867 grams 4 153 3 780 2 898 3 800 3 981 3 473 3 808 4 300 3 234 3 752 3 446 3 799 3 261 3 871 3 704 3 684 grams 7 700 7 990 8 149 9 650 8 606 8 593 8 865 9 130 8 800 9 747 9 915 8 695 8 800 9 110 8 950 8 847 grams 2 665 2 864 1 871 1 588 2 239 2 665 1 559 1 899 1 814 2 580 1 701 2 608 2 183 2 268 1 814 2 155 2b .... 3b 4s 7s 8b 9s 10b 12b lob 16b 17b 18b 19b Average Type C Intermediate 2s 104.3 101.6 101. 3 102.5 102.1 100.7 100.2 99.3 104.3 102.5 104.3 104.3 104.3 101.6 98.9 102.4 29 555 28 654 29 068 30 816 27 672 28 558 27 680 28 977 27 837 30 704 28 736 28 418 28 274 32 385 28 024 29 024 33 545 32 909 32 345 31 422 35 139 33 854 32 691 32 141 33 856 30 115 31 235 33 916 34 580 31 740 32 263 32 783 9 248 9 692 10 210 8 944 9 438 8 644 9 415 9 334 10 673 8 738 9 493 9 066 9 685 9 526 8 785 9 393 4 194 4 274 4 150 4 181 4 022 3 629 4 014 3 770 4 991 3 459 4 050 3 898 3 982 3 840 4 330 4 052 6 655 7 286 9 670 9 000 8 134 8 454 7 552 8 145 8 656 9 414 10 570 9 527 7 922 8 107 7 945 8 469 2 098 3 062 2 239 1 956 2 211 1 956 2 098 1 927 2 069 2 268 2 183 2 523 1 701 2 154 2 041 2 166 4b 5b 6b 7b Sb 9s lOb lib 12s 13s ... 15s 16s 18b 19b Average Type D Rangy lb 99.3 29 958 31 190 9 974 4 026 8 514 1 474 2b 101.2 26 694 34 970 10 122 4 118 8 537 1 927 . 3b 102.5 27 115 33 243 9 307 4 785 8 920 2 268 4b 105.2 25 055 31 796 12 770 5 027 9 965 1 531 5b 103.9 27 114 33 097 10 3''7 4 730 8 980 2 353 6b 104.3 28 062 32 591 11 001 4 949 10 015 1 588 7b 107.0 24 603 36 393 11 442 5 111 10 500 2 239 9b 100.7 23 787 33 969 10 856 4 086 9 785 2 098 12b 101.2 29 257 31 501 10 107 4 441 8 500 2 012 14b 101.6 30 079 32 821 9 206 4 798 7 893 2 665 15s 103.4 25 064 33 916 11 315 4 276 8 852 2 523 16b 102.1 31 006 32 858 10 128 3 934 8 645 2 381 18b 101.6 30 342 29 228 10 552 4 306 8 165 1 474 19s . 99.3 23 665 35 312 10 820 4 027 7 785 2 183 20b 100.2 27 094 32 914 10 033 4 042 8 876 2 722 Average 102.2 27 260 33 053 10 531 4 444 8 929 2 09(5 Average of all types. . . 102.1 28 715 32 343 9 597 4 060 8 748 2 139 = barrow; s = sow. 'Including the caul and mesentery fats. Including snout and ears. 1DS9] ENERGY AND PKOTKIX REQUIREMENTS OK GROWING SWIM: 517 TABLE 21. PERCENTAGE COMPOSITION OF Li: \.\ SAMPLES FROM THE FAT Pics: FlIOT K\!>ERIMENT Pig No. Dry substance Crude protein (Nx6.0) Fat Gross energy per gram Type B Chaffy 1 pet. 39.68 40.90 11. or, 39.90 11.7(1 38.06 40.93 40.66 35.21 40.69 40.78 38.19 35.45 40.10 38.01 39.42 pet. 16.74 16.68 16.50 16.50 16.98 16.14 17.82 18.18 16.62 15.72 16.80 16.74 16.38 17.40 16.80 pet. 22.32 20.57 23.71 21.24 22.70 20.48 22.66 20.76 16.29 23.41 22.94 19.80 16.91 22.05 19.16 21.00 .86 .89 .85 .88 .88 .89 .93 .86 .87 .85 .83 .85 .87 .91 .00 .87 sm. cnlx. 3 088 2 852 3 2(13 3 017 3 038 3 071 3 102 3 068 2 71.-> 3 059 3 229 2 934 2 626 3 025 2 sr,c, 2 997 3 4 5 7 8 !> . ... 10 11' 1 .-> 16 17 18 10 Average Type C Inti tin 2 43. 56 1 42.84 45.32 44.98 43.36 12.36 17. MI; 43.30 41.68 41.10 47.51 43.93 40.1.' 42.60 43.41 13.56 16.61> 17.10 16.98 15.72 16.56 15 . 84 16.56 16.50 16.02 17.22 16.80 16.38 16.68 17.04 17.16 16.61 23.591 21.88 21.23 28.04 22.80 25.40 22.11 24.57 23 . .V. 22.55 22.92 25.91 22.36 22.49 24.42 23.59 .87' .92 .91 .84 .90 .89 .89 .85 .87 .87 .85 .84 .81 .85 .83 .87 3 188* 3 001 3 024 2 440 3 085 3 232 3 039 3 210 3 067 3 140 3 136 3 382 3 318 3 077 3 439 3 110 4 .-> t; 7 8 '.i 10 11 12 13 15 16 18 10 Average. . . Type 1) Huntry 1 43 56 15 42 24 54 80 3 122 2 44.39 16 44 23 44 .98 3 116 3 40 48 17 40 20 56 95 3 030 4 45.36 16.20 25 C.O .'.If, 3 326 .-> 40.80 16 38 1"' C, t .92 3 200 (i 40 83 15 78 22 58 81 3 227 7 44.43 16.44 21.32 .89 2 971 44.65 17.04 22 89 .98 3 196 12 41.97 16 20 24 68 80 3 166 14 45 84 16 98 22 35 1 01 3 085 15 42.07 16.32 22.80 .83 3 004 16 37.08 16 62 19 61 .88 2 913 18 39.77 16 02 22 00 89 2 972 19 .. 39 82 17 04 21 03 95 3 069 20 38.52 16 56 21 28 .93 3 004 Average 41.97 16.46 22.49 .91 3 093 Average of all typi-.- 41.65 16.62 22.36 .88 3 070 'This sample was accidently thrown out before it was analyzed. The percentages given are the averages for that type. 'Calculated using 5.7 calories per gram of protein and 9.5 calor es per gram of fat. ; - ?:-._: : :-: lr... r 7;.- --_I; TI _I- 7n..i j;s 7 .-.- 7v.~ Ji ^ < KJB " < J i, ; <4i > ~Z~ ~ .Xi 3f 7 *E *fe * LSI <. iT .. Jfe Zte BE II > ^f.". _ L *. -. ,. .s - .r, '- * Ji - 'C -' - -S - :_ Jl .t 11 S &^K _IB ' JtoK^. ^ -X3K GOTP ..'') ?';' lT "T"!r BHIEBBMI ^ TT - : . ; . .** : ^* ~"! , :,: '..::..". - ':."; n . : .- Ife^ I *. ^ .-^rijj..." ;'- 4 t -. > . . ' B _ - -^ R.^ BB DflP K -fe - * JtV.O -jtcm '.- .2. >fi. - . - _\ r . a&jB - . x *. '- 9B "l M- - - - : ^3*. . 1 * r- \ '. '*- ' ttm . 'Vi_ ai JHT . atmt mm v *' -. * -^>- -i^L .. V v- JtaoHOP : 520 BULLETIN Xo. 3^ [May TABLE 25. PERCENTAGE COMPOSITION OF ENTIRE CARCASSES' OF THE FAT PIGS: FIRST EXPERIMENT Pig No. Dry substance Crude protein (Nx6.0) Fat Ash Gross energy per gram Type B Chuffy 1 pet. 44.81 50.91 50.13 46.71 50.73 48.26 47.05 50.80 45.97 49.14 47.37 48.28 47.86 49.00 49.42 48.43 pet. 11.30 11.05 10.86 11.13 11.07 11.15 10.70 11.19 11.16 11.24 10.40 10.99 10.75 10.41 10.53 10.93 pet. 30.20 35.34 35.33 32.17 36.01 35.24 33.53 36.40 32.29 34.95 33.78 33.91 34.11 35.01 35.45 34 . 25 pet. 2.01 2.07 1.98 2.11 2.06 1.94 2.08 2.17 2.10 2.05 2.14 2.04 2.13 1.89 1.92 2.0.5 am. cols. 3 586 4 055 4 034 3 677 4 055 3 917 3 824 4 091 3 733 3 938 3 872 3 864 3 831 4 042 4 017 3 902 2 3 4 5 7 .... 8 9 10 12 15 16 17 18 19 Average Type C Intermediate 2 49.17 50.19 51.10 51.21 50.40 50.85 51.52 50.83 50.33 49.90 49.17 49.08 53.29 51.72 50.55 11.40 ll.fi \ 11.47 10.77 1 1 . r>2 10.94 11.38 11.22 11.52 10.69 11.00 11.19 11.07 11.33 11.40 11.24 34.44 34 . 66 34.84 38.70 34.20 36.73 34.55 36.22 34.86 35.12 34.34 34 . 87 34 . C.5 38.84 36.94 35.60 1.95 2.23 2.13 1.92 2.09 2.15 2.19 2.20 2.07 2.00 1.98 1.94 2.05 2.10 1.96 2.06 3 893 3 888 3 941 4 234 3 928 4 071 3 972 3 988 3 845 3 971 3 883 3 873 4 017 4 242 4 196 3 996 4 6 7 8 n 10 11 ... 12 13 15 16 18 19 Averaee. . . Type D Rangy 1 51.27 10.72 37.51 2. 19 4 179 2 49 7<> 11 62 34 84 2 38 3 972 3 48 03 11 58 34 3fi 2 10 3 824 4 48.34 1 1 . 50 33 . 35 2.40 3 821 5 48.21 11.35 31.91 2.22 3 811 6 48.49 11.20 34 52 2.18 3 902 7 49 02 11 77 32 85 2 34 3 738 9 48 85 1 1 91 32 25 2 51 3 783 12 50.56 11.53 35.38 2.17 4 022 14 52.95 11.69 36.50 2.16 4 144 15 ... 46.99 11 77 31 79 2.28 3 656 16 50 18 11 68 35 61 2.02 4 084 18 49.28 10.92 35.78 1.97 3 947 19 17 7C 12.12 32.53 2.44 3 786 20 48.09 11.64 33.03 2.18 3 852 Average 49.18 11.53 34.15 2.24 3 901 Average of all types 49.39 11.23 34 . 67 2.12 3 933 'On live-weight basis. W29] KXEKGY AXD PROTF.IX RF.QUIKKM KNTS OF ( ii;< i\VIX(i S \VIXE 521 TABLE 24. PERCENTAGE COMPOSITION OF COMPOSITE SAMPLES FROM THE FAT PIGS: FIRST EXPERIMENT Sample Dry substance Crude protein (Nx6.0) Fat Ash Gross energy per gram Blood . . pet. 19.80 pet. 17.82 pet. .04 pet. I .2-2 sm. cals. 952 21.50 10.44 9.69 1.38 1 523 Hair 1 93.19 83.58 2.49 4 868 Skin 90.00 37.08 51.85 .35 7 816 'On the air-dry basis. This sample includes tin- tm-n ills. 'This sample includes the ears and snout. what fatter on the average than the other types, a distinction evident for all samples except the offal, but the differences are slight and of doubtful significance. The Rangy pigs, because of a slightly larger proportion of bone, contained a higher average percentage of ash in the entire carcass. AVhile this is very probably a significant type difference, it is not important quantitatively. TABLE 26. -COMPARISON OF THE AVERAGE PERCENTAGE COMPOSITION OF DIF- FERENT TYPES OF FAT PIGS AND OF PRINCIPAL ANALYTICAL SAMPLI FIRST EXPERIMENT Type Dry substance Crude protei/i \x6.0) Fat Ash Gross energy per gram Lean Chuffy pet. 39.42 43.56 41.97 pet. 16.80 16.61 16.46 pet. 21.00 23.59 22.49 pet. .87 .87 .91 sm. cals. 2 997 3 119 3 093 Intermediate Rangy Fat Chuffy 84.24 86.12 84.11 3.90 3.49 3.78 78.64 81.10 79.92 .16 .14 .15 7 585 7 795 7 688 Intermediate Rangy Bone Chuffy 60.72 60.94 60.13 18.73 18.98 18.80 21.04 22.48 21.75 19.10 17.68 17.20 3 118 3 262 3 195 Intermediate Rangy Offal Chuffy 27.79 27.90 27.06 11.83 1 1 . 79 12.18 12.83 12.76 11.51 .82 .81 .86 1 960 1 991 1 899 Intermediate Rangy Entire carcass Chuffy 48.43 50.55 49.18 10.93 11.24 11.53 34.25 35.60 34.15 2.05 2.06 2.24 3 902 3 996 3 901 Intermediate Rangy 522 BULLETIN- Xo. 323 [May, The absence of marked type differences in the composition of the carcasses of pigs is very strikingly shown in the case of the dressed carcasses. In Fig. 2 longitudinal sections of three typical carcasses of the Chuff y, Intermediate, and Rangy pigs are pictured. They differ distinctly in appearance and in market finish, but when they are dis- sected with a knife into lean, fat, and bone and analyzed chemically, no pronounced differences arc evident except possibly with respect to Fit;, i'. REPRESENTATIVE CARCASSES OF CIIUFFY, INTERMEDIATE, AND KA.VCJY PIGS SLAUGHTERED AT APPROXIMATELY 225 POUNDS LIVE WEIGHT: FIRST EXPERIMENT While the pigs of these types differed distinctly in appearance and market finish, the carcasses did nut differ much in chemical composition. the bone and ash content of the Rangy pigs (Tables 2i and 28). Apparently these carcasses differed in their distribution of tissues and of nutrients but not in their content of them to any but an inappreciable extent. Composition of Gains. The amounts of organic and inorganic nutrients contained in the carcass of an animal measure the amounts of food nutrients that have been used for growth and fattening; 19H9] ENERGY AND PROTEIN REQUIREMENTS OK <'; ROWING SWINE 523 TABLE -7 \\I:' BONK. IN DKE sto CAR' IHK I-'AT PK;>: FIK-T EXPERIMENT rage Type weight of dressed Lean Fat Bone Skin rarcass pet. pet. pet. pet. Chuffv 43.45 39.06 5.13 Intermediate 14.H4 37.00 5.52 Rangy 73.61 44.92 34 . 74 14.32 6.01 TABLE 28. AVERAGE PKKCI MPO-ITION OK DHE-SED ' THE :HST EXPERIMENT Type Dry substance Crude protein rt.O) Fat Ash Gross energy per pound Chuffv pet. 62.31 pet. 13.06 pet. 4.5. 12 pet. _ : cols. InternieJiati- 64.30 13.34 2.71 2 319 Rangy 62.19 13.59 44.44 2.93 2 252 . they are measures of the requirements of nutrients, for these purposes, from the time of conception to the time of the examination of the carcass, due consideration being given to the interchangeability of foods in metabolism. It follows, therefore, that increases in the amounts of nutrients contained in older, as compared with younger, animals measure the amounts of nutrients used between those ages for growth and concomitant fattening and measure also the corre- sponding requirements. The composition of the gains put on by growing and fattening animals is a most important and fundamental consideration to a study of their food requirements. In computing the composition of the gains in weight of the fat pigs during their feeding period some estimate must be made of their composition at the beginning of the experiment. Such an estimate may be made oil the assumption that the fat pigs in each type possessed the same composition at their initial weights as the control pigs of that type slaughtered and analyzed at the beginning of the experi- ment. In Table 29 will be found the estimates of the percentage com- position of the gains put on by the fat pigs from initial weights averaging 72 pounds to final weights of 225 pounds. In this table the pigs in each type have been arranged in the order of decreasing rates oi gain during their feeding periods, for the purpose of determining whether the composition of the gains was related to the rate at which they were made. It is conceivable that the slower gains would represent more growth and less fattening than 524 BULLETIN Xo. 323 [Ma-y, TABLE 29. PERCENTAGE COMPOSITION OF GAINS OF THE FAT PIGS: FIRST EXPERIMENT Pig No. Average daily gains Percentage composition of gain Dry substance Crude protein (XxO.O) Fat Ash Gross energy per gram Type B Chuffy 1 Ibs. 1.22 1.20 1.18 1.18 .18 .14 .13 .11 .11 .08 .08 1.07 1.06 1.06 pet. 49.0 53.6 50.5 54.8 58.2 53.3 56.6 50.7 53.8 52.0 55.8 56.2 53.9 52.0 " . I 53.8 pet. 11.4 10.1 11.2 11.3 11.0 10.5 11.3 11.2 10.9 10.6 10.2 11.1 11.2 10.1 10.8 10.9 pet. 34.4 40.1 36.1 41.0 42.3 40.1 42.3 37.7 39.7 39.0 42.4 41.5 41.7 39.0 42.3 40.0 pet. 1.90 1.72 2.07 1.96 1.97 2.06 2.15 2.01 1.93 2.00 1.74 1.97 1.78 2.09 1.85 1.95 srn. cols. 4.00 4.53 4.03 4.48 4.72 4.35 4.64 4.23 4.39 4.33 4.66 4. 55 4.48 4.36 4.70 4.43 18 4 12 v> 17 9 10 16 8 19 7 15 3 Average. . . . Type C Intermediate 2. 1.28 i . 20 1.26 1 . 23 1 . 22 1.20 1.19 1.18 1.18 1.15 1.15 1.13 1.09 1.08 1.07 54.1 58.2 :.:, . 7 58.2 55.7 58.0 .-,.-> . 1 55.0 58.1 57.0 58.5 .V.I.I 57.2 56.9 11.3 11.3 10.8 11.5 11.8 10.8 11.3 10.2 11.1 10.2 10.6 11.1 11.1 11.3 11.7 11 1 39.5 40.5 . a 40.6 42.6 40.0 41.4 41.3 41.0 46.9 43.8 42.6 44.4 44.5 40.5 42.1 1.84 2 . 1 r> 1.95 2.18 1.97 1.88 2.04 1.86 1.82 1.72 2.08 2.16 2.01 1.83 2.01 1.88 4.35 4.55 4.70 4.41 4.51 4.40 I , :,4 4.53 4.42 4.96 4.69 4.38 4.73 4.91 4.52 4.57 9 16 4 11. . 13 12 15 8 10. 18 . 19 7 Avo'aie. . . . Type D Rangy 16. ... 1.20 -1.20 1.09 1 04 1.02 1.01 1.01 .99 .97 .94 .91 .90 .88 .82 .76 56.9 55.4 54.0 56.7 58.4 54.1 59.7 63.6 56.0 53 . 2 52.1 54.9 56.8 .->4 . 7 54.6 56.1 11.6 11.5 11. 1 11.6 10.3 11.4 11.4 11.6 11.6 11.3 11.8 12.3 11.9 11.0 10.5 11.4 42.7 i i . :, 38.1 41.9 45.3 39.2 44.6 46.7 39.7 40.3 36.9 39.7 39.8 41.3 42.0 41.2 1.96 2.11 2.17 2.42 2.14 2.43 2 . 00 2.41 2.33 2.00 2.19 2.50 2.59 2.14 1.83 2.22 4.76 4.57 4.43 4.64 4.89 4.37 4.88 5.10 4.36 4.34 4.13 4.47 4.51 4.52 4.48 4.56 20 5 2 1. . 4 12 14 7 3 15 19 9. . . 6 18 Average. . . . Average of all types 55.6 11.1 41.1 2.04 4.52 1929] ENERGY AND PROTEIN REQUIREMENTS OF GROWING SWINE 525 the more rapid gains and would contain, therefore, more protein and mineral matter and less fat. dry matter, and energy. A study of the table, however, shows thai this was not the ease. There appears to be no progressive change in the percentage of any of the analyzed constituents or in the .unss energy of the gain per gram with progres- sively decreasing rates of growth. Also, a comparison of the rates of gain with the composition of the carcasses of the fat pigs reveals no appreciable correlation. No considerable average differences exist among the three types of pigs in the composition of their gains. A distinct tho slight in- crease in the percentage of ash in the gains of the Rangy pigs as com- pared with the oilier types seems to exist, while the gains of the ('huffy pigs were somewhat more watery and lower in fat and energy than those of the Intermediate type in particular. The differences, however, are so small that the average composition for the entire 45 pigs may be considered as applying to Poland China pigs in general. It may be said, therefore, that during growth and fattening from about 70 to 2.") pounds, pigs of this breed put on gains containing, on the average. 56 percent of dry matter. 11 percent of crude protein (N x 6.0) a . 41 percent of fat, and 2 percent of mineral matter, and possessing an energy value of 4.5 calories per gram, or 2.1 therms per pound. Hence it may be computed that for pigs gaining 1 pound a day. the average daily increment in protein would approximate .11 pound, in mineral matter (ash) .021 pound, and in gross energy 2.1 therms. For daily gains of 1.5 pounds per day. representing more nearly the maximum rate of gain, the daily increments would be .17 pound of protein, .031 pound of mineral matter (ash), and 3.1 therms of gross energy. These figures may be taken to measure the requirements of these nutrients for growth and fattening, tho obviously they cannot be covered by equal amounts of digestible food nutrients unless allow- ance is made for the losses of the latter in the course of their assimi- lation. On the assumption that the average biological value of the protein 2 of good farm rations may be taken to be 60, and that the metabolizable energy of feed is utilized to the extent of 75 percent, then it may be computed that for pigs gaining at rates of 1 pound and 1.5 pounds daily the requirements of digestible protein for growth and fattening would approximate .18 and .28 pounds respectively, and the requirements of metabolizable energy 2.8 and 4.1 therms respec- tively. These requirements are, of course, to be added to the mainte- 1 If the factor 6.25 is used, the average percentage of crude protein increases from 11.1 to 11.6. * The biological value of a protein is the maximum percentage of the digestible protein that is available for the maintenance and growth of animals. 526 BULLETIN No. 323 [Hay, nance requirements, which would vary with the weight of the animal. The question of the total food requirements of growing pigs will be considered in a later section of the bulletin. The nutritive ratio of a gain containing .11 pound of protein and 2.1 therms of energy per pound is 1 to 9, and that of the estimated quantities of digestible protein and metabolizable energy required to produce a gain of this character would be 1 to 7.4. Apparently a fairly wide nutritive ratio is consistent with maximum growth. Distribution of Added Nutrients in the Carcass. Another ques- tion of practical significance concerning the growth and fattening of farm animals relates to the distribution of the added nutrients among the different anatomical divisions of the body. From the weights of samples of the control and the fat pigs, and from the percentage composition of these samples, the distribution of nutrients among the more important divisions of the carcass may be computed. Similar computations may also be made relative to the gains in nutrients. The results of such computations for dry matter, crude protein, ash, and gross energy make up Table 30. In the carcasses of both control and fat pigs the greater part of the dry substance was contained in the lean and fat tissues of the dressed carcass, and this is even more true of the gains of dry sub- stance, of which the edible meat of the dressed carcass contained an average of 74 percent. The crude protein was more evenly distributed thru the carcass, tho of the gain in protein in the fat pigs an average of almost 60 percent (57.7) was added to the boneless meat of the dressed carcass. Seventy-five to 80 percent of the mineral matter in the carcasses was located in the bones, and 80 percent of the mineral matter added during growth was deposited in the skeleton. The lean of the carcass contained 12 to 13 percent of its mineral matter and received over 13 percent of the added minerals. As regards gross energy, even in the control pigs the fatty tissues contained more than any other sample, namely, 35 to 47 percent ; in the fat pigs 50 to 53 percent of the total energy content of the carcass was located in the fat sample. Of the gains of energy, 54 percent went to the adipose tissue and over 24 percent to the lean meat on the carcass, a total of 78 percent for the boneless meat of the dressed carcass. Thus during growth and fattening 74 percent of the increment in dry matter. 58 percent of the increment in protein, 14 percent of the increment in mineral matter, and 78 percent of the increment in gross energy were added to the boneless meat of the carcass, economically the most important part of the animal. Relation of Feed Consumed Above Maintenance to Gross En- ergy of Gains. The provisions in the plan of this experiment for the individual feeding of the pigs, for the determination of the mainte- nance requirements of feed, and for the slaughter and analysis of 19S9] ENERGY AND PROTEIN REQUIREMENTS OF GROWING SWINE 527 i 5 s I\H \ i | = o 5 3 S - a ; &. '5. : - 2 O * K^ c j ^, ~ Vi - 5 5 .. = ,. C .- "- O y f- ' < -- "a J 1 < L - i S - ^ JJB i / _ *P 00 : * a a : - ^ C ;.. "o - : - s 5 - i 3 i ** s Q 5 "o $* : - C P "* [| : . - c- - - ' - d = H . J I "/. 00 3^ Q "3 M r si ' E- 5 Z : o :o a H : s S E- s| : - i - \\ -5 . - D 3 OQ X -, _- - < i O 5 ?g a u j - < - .r t- CO !C t^ r? <~- _ -T ~ re r - e ?! c r r- r t~ r- 5 zi d ' : c t>i ri r! c r. r. r. r r re r. t~ z - : ~ ' -/. r*? oc cc x * :i d "' \\ - ~ Miii-ln. in." i i.i- . .-ml .-HI.I in.-: entei \ s S ~ r^ rj ,e ^ oo r~ * ^ * o re o CJ t>. t- X X *" -; ^ *c o - re _ M f n SC CO t~ - o * -- = r- 23 re i t- .- ~> f ia X -. cs !>. C - re re w- _ r IN re i.e (^ - ?i r< .- - - OB _ a J t^ re L- t- - re - - t- X - >-: - s W 30 re r~ - - US - - - ~ oo LI re / - - r - M M -! r. i~ re r r s M r o re ~ - - CO O _ CO TT t^ !N - r- r~ - o - -. = / t- O O O M ; - e o> M re t^ . U t^ r ~ re ue 3C t^ - r r ; r r -i re S t- ~ - - j c = a - c ^ -/ c ; i -r a 528 BULLETIN Xo. 323 [May, both control and fat pigs render possible a comparison of feed con- sumed above the estimated maintenance requirements with the com- position of the gains put on. The ration fed can be considered liberal in its content of protein and mineral matter and adequate, in all probability, in its content of the necessary vitamins. Hence the amounts required for maintenance were determined by the net energy content of the ration, and the gross energy of the gains put on was determined by the amounts of net energy consumed above the mainte- nance requirements. On the other hand, the relation of protein and mineral matter consumed to the protein and mineral matter of the gains is not highly significant even if a maintenance requirement of protein and minerals be deducted from the intakes since it. is probable that in all cases an excess ot these nutrients was consumed. The utilization of the feed consumed, or of the feed energy con- sumed, would be best expressed by relating it to the sum of (1) the energy expended in life and activity and (2) the energy stored during growth and fattening. Unfortunately the data secured in this experi- ment do not permit an expression of these two factors in terms of energy or in any common terms. Hence the two cannot be summated. An alternative method of procedure is to determine the energy ex- pense of the pigs in terms of feed, as was done in the maintenance experiments, deduct the estimated feed used for this purpose from the total feed consumed, and relate the excess feed to the gross energy of the gains secured. This method assumes, somewhat gratuitously, not only that the basal metabolism and the activity of the maintenance pigs per unit of weight was equal to that of the fattening pigs, but also that the utili- zation of feed energy for these purposes is not affected by the level of feeding, that, is, by the feed consumption per unit of weight. Ad- mittedly no evidence can be offered for the essential correctness of either assumption; in fact there are good reasons for believing that the latter assumption is not true, tho how greatly it diverges from the truth cannot at present be said. However, since this method is the only one that can be used under the prevailing circumstances, it has been applied to the data at hand in Tables 31, 32, and 33. The logic of the method can probably be best explained by follow- ing the calculations for one pig. Pig 1 of the Chuffy type in 129 days of feeding increased in. weight from 73 to 230 pounds, making a total gain of 157 pounds, this gain containing 284 therms of gross energy. The total feed consumption was 632 pounds. The estimate of the amount of feed used for maintenance is based on three values : (1) the average weight of the pig during the feeding period, 143 pounds, obtained by averaging all of the weekly weights; (2) the average daily feed requirement per 100 pounds live weight (weight ratio), 1.41 pounds, obtained by averaging the type averages for the two 19S9] i:GY AND PROTK.IX RKOCIKKMKNTS OK Ci;o\vi\t; SWIXK 529 ^; o o =0 05 ri b. * co _j - o O k o o CO oo C 71 C- N " ^ c CO 5 co CO / 00 ^ ? o g i h- O - o --T IN ~ ^. c -\ CO "C co t. IS CO -r oo ,. o 01 S> t^ ~~ 71 "" 2 (N CO s -H IN 1- .7 s CO co _ r . ""* 1 'j a q CO i-O ; r ~~ 71 ~ '" ?4 CO "7; CO -* 71 71 c? ~ 71 i - : ^ 7_1 71 " (N CO ~ CO ~ O s. x & '" ; '-' 3 -f r N 1- rt - 9 71 IN CO C 71 "" ^. N co ^S co 1 ?, r: . - -r "J 1 C-1 CO 5 ^ .- (, 1 nn e\pe aintcnaiice S a I'er licail . . tal feed. . ^ 8 tenance . ross energy Pt energy of ^ w < Q *-. E-c c- H O ;.,,. - - - - r - - - I 38 - _ _ _ 1 _ _ _ - - - - - - - - - - _- - - - - : . J - _ - ; : - z z A ? at;-: : : i? - v.: : *.; . - - - - - " - , - . - - - - a - - - - - - - - - - - _ _ - - - - - -- ' - - - - ' - - j - - - - - - - - _ ~ ~ - - - -. - - - . ' : - - - - ~ - ^ - - - - - -. a : = : - - = - - : ' - ~ - n - - - - - * ~ - - - _ _ - .. - | - - - . : ; - . . ~ or - . - - ~ ~ i - - - - r c - ^r 7 _ - - - - - - - - - - - : _ I - - - ' - - - i _ _ | : ; - rz --".".:., ""v* N :. 'ti;! tuiiifititffiHiiiiiiiiiiniMn uniif MUM TiHifln IT nnJ 111) and (3) the br -;r" .iij^ oa *-x?fraDfl!:^ 1:2*. F'W ^ia* Taar niw- iTin&K- ..ijdlbr nanee iNnniraojent K thus tscmnMK. . . tattal at a*H pan&. Henee the aawont f foed eonsonwd above was ? 3161=371 poands. Since this anwont rf i ri~- :: iS^ thenu :: ma^y m tint bm :: TBJnttimrr ta- net evn^r f tihe feed per 1QD poo^ is qpul " " -JmB. Fmr n&H- 15 Cbidhr | the a^era^e nvtt eneify xatoe aT the Urad imjNMiiBdkivia^ CUD &r the Bungr . " - thenK. Hovero; the twven types ramett he auideicd ajgwfieaunt in Tievr f ratfter v& rang? the on^rniiral csKinattK mithm eaeh nyy * - Tfce aveaa$e far tfe A art eno^r TO! IK :^ r* J. t&emK per 1490 pionds B naBeoi lower Ufa* mdd W exporiled firan Anwcj V efiltnntes off the Mt ewrfy : r OBTOL taoia^e. and mMlraqri; for p%& T%e aTerage ratioa : : 7 -itfat 7 cu ctaBBained 1C pernt f com. $ percent of . ami 1(6 peroeBt rf mfatat addingiL Taiimc Armar-T's vaflnaw s; per 1 ponds nrrtead -cc -*.P. therm, as cwpBted JU~.-- : d ~.lll!f *3T7^-T I 1T!>*1I ". A l>*''~Ii si <>^ > .' C .'"' ".* Ur Cjf! r ?* L '^* ht imerwd VBfii the ranks f the next TOUT'S experneBt are SECOXD 1LXPE.RIMEKT The {&iHnKa]I wank nn the- WKtavd petr"* experiment ((19S^-24') mas tftfmceiratfii wtidk the ' Jy ttrpe of Foawd Clkina per the iBttemediber I and the Bangr Itrpe (TJT D ). All mmamJ ini March except a verjr aaoD mamaa&y - .!-* to he ttartted : - r * '.i :: - i_r. -.-./ and Bangir pifs; as thejr rcaehfd an the eantral ff-azs of the Arae types type werc- dbm@teercd Jnly 3^ fii of the larter- type m Jirfy 1L and fete of the Very Chaffy type on Jvly 17. :.L? ^ praetieanlc "^- i.n-:~^: ::' all pises aaaJhraiwfl were divided into On the day of sdbaelbflcT the dremed carcaas was piepaied fi^.. UDft? flnVBDDIBB. 'In nJBfflDD -i.c -lair: .!? BBWHBfl I.;:; "'' !; .Vi' r " - fiH .''.iil('Ti;OT MBB :? -: . ' Oat Ha*. -Y/A r - ' . .. . . .- :.; 41 i ; . ! . - - . - - - e - . . ' . IH \ HI - :- i T - . ' ' . - ' ' . za.8 ttj . ' ' . -; * . 2r- I 4 v* * >2 4.32 1.36 2.90 17. 4O . 5.08 8.4O 3.76 1.24 3.22 23 23.0 5.22 6.84 3.08 1.32 2 <2 14 24.2 5.20 .96 2 rx 15.60 22.2 4.55 3.18 1.24 2 V4 15.14 A ~~ 24.3 4 * 7.80 3.82 1-22 2.94 15.76 A ^L* 49 5 24 2 100. ON 3 ^t 6.18 9.16 .22 .58 3 78 20 74 . 32. 10 36 .98 .46 3.84 22 64 32. 6 52 10 i* .46 .TO 3 76 22 00 31. 6.30 9.72 .62 3.66 20.70 34. 6.38 - ** .40 .66 4.06 22.10 32.0 6.23 9.86 6.36 1.60 3.82 21.64 A ^TL. 45 ^ 29 4 - (IT 100 '. 3:4 6.01 10.66 6.18 3.94 22.62 33.3 6.66 11.60 5.28 1.76 4.56 2.? J" 23 34.8 6.45 12.30 5 46 2 10 4 58 3.60 1 4. 20 21.44 33.* 6.1* 1O.64 6.42 1.96 4.10 23 12 Av*r** 32.9 6. IS 11.40 S.40 1.9) 4.28 22.96 A -r^t- tapcraw C4 si 100 avenge analyses to this material, obtained in the experiment of the preceding year, the weights of nutrients per pig were estimated. The above general description of the preparation of samples in the second experiment apply to the handling of the control pigs except for a farther simplification. Instead of analyzing the offal samples individually, they were composited for each type. The slaughter weights of each of the control pigs and the weights and percentages of "fill" are collected in Table 34. The contents of ENERGY AXD PBOTEIN BEQCTKUlEXTS OF GROWING 535 TABLE 36. PERCENTAGE COMPOSITION OF DRESSED CARCASSES or THE COXTBOL PIGS: SECOND EXPERIMENT Xo Dry N~x6.0) Type A Very Chuffy pet. pet. ;-.r *. cat*. 14.6* 2* 24 3.16 3 452 45.39 14 ?2 25. &S 3.31 3 2C-2 30. 12 12.78 33.04 i >22 50 19 - n 31.19 3 2-i 3 843 40.85 14.58 n.n 3.33 13.91 2*. 25 3.3* 3 4->4 Type. C Intermediate 3 49 84 12 >; 33 07 2 94 3 Si5 o y.~j 1 51.40 12 fj* 33 5 -- 3 <<$ 48.79 13.56 32.02 3.4O 3 734 Average 4^ 51 30.96 3 "2 1 3 625 TypeD R*. ^ 3.27 4 187 49 ^ 13 01 31 47 3 20 3 752 Average of ail types 13.23 30.23 3 17 3 614 the alimentary tract represent a fast of approximately 18 hours. The average percentage "fill" for all the control pigs was From the percentages of separated fat in the dressed carcass it appears that the pigs of the Intermediate type were in the best condition at the beginning of the experiment. The per- centages of lean. fat. skin, and bone were surprisingly similar for the Very Chuffy and Rangy pigs The results of the chemical analysis of the dressed carcasses for the pigs of the different types (Table 36) do not indicate any eon- rable differences in fat content. According to these values the Very Chuffy pigs were in general the least fat and the highest in protein and ash. With these samples, as with all others in the two type experiments, the gross energy was determined directly in the bomb calorimeter. The chemical analyses of the composite offal samples for the three types of control pigs are given in Table 37. 536 BULLETIN- Xo. 323 [May, TABLE 37. -PERCENTAGE COMPOSITION OF COMPOSITE OFFAL SAMPLES FROM THE CONTROL PIGS: SECOND EXPERIMENT Type Dry substance Crude protein < ri'i ill /in-i-i /it Control pigs of first experiment 18.83 ILL'S u.xn Control pigs of second experiment 20.86 1.1. i'7 3.01 THE MAINTENANCE EXPERIMENTS Maintenance trials were run on a number of pigs in each of the three types at the initial weight of 55 to 70 pounds and at the market weight of 225 pounds. In addition to the feeding experiments to determine the amount of feed required for the maintenance of weight, digestion trials were run upon some of the pigs in each of the two maintenance groups. Besides the ordinary determinations on feed a IK! feces, these digestion trials included gross energy determinations upon feed, feces, and urine, permitting the estimation of the metabo- lizable energy of the ration. Since the maintenance experiments were planned only with refer- ence to estimations of the feed utilization of the 225-pound fat pigs. the maintenance pigs were fed a ration approximating closely in com- position the average ration that these fat pigs consumed during their fattening period. This average ration contained 78.5 percent of shelled corn, 6.6 percent of tankage, 13.2 percent of wheat middlings, and 1.7 percent of alfalfa meal. The corn was fed whole and the other constituents as a ground mixture. The average percentage com- position of the feeds used thru the maintenance and fattening periods of the second experiment is summarized in Table 39. The young maintenance pigs of the Very Chuffy type received daily 6.5 ounces of whole corn and 1.5 ounces of a mixture containing 8 parts of middlings, 4 of tankage, and 1 of alfalfa meal. The Inter- mediate and Rangy pigs averaging somewhat larger in weight, re- ceived daily 7 ounces of corn and 2 ounces of the mixture. The fat maintenance pigs received varying amounts of corn and the same mix- ture, averaging closely 4 parts of the former to 1 of the latter. It was hoped that the maintenance feeding could continue until each pig was at constant weight on constant feed for eight weeks. 538 BULLETIN Xo. 323 TABLE 39. AVERAGE CHEMICAL COMPOSITION' OF FEEDS USED THRUOUT THE SECOND EXPERIMENT Feed Dry sub- stance Crude protein N-free extract Crude fiber Fat Asli Gross energy Per 100 pounds Per gram Corn Tankage Middlings. . . Alfalfa meal . pet. 84.68 89.87 87.18 85.72 pet. 8.86 56.13 16.13 15.58 pet. 70.07 5.69 59.62 31.67 pet. 2.76 2.86 4.70 28.18 pet. 1.65 4.51 2.83 1.29 pet. 1.34 20.68 3.90 9.00 therms 169.14 178.31 180.03 175.36 sm. cals. 3 729 3 931 3 969 3 866 With the larger pigs, whose maintenance feeding started in December and continued into March, this ideal was realized; but with the younger maintenance pigs, whose feeding started July 21 and in some TABLE 40. AVERAGE FEEDING RESULTS OF THE MAINTENANCE TRIALS ON THE YOUNG PIGS: SECOND EXPERIMENT Pig Xo. and sex 1 Initial body weight Maintenance body weight Average daily feed Feed per 100 pounds body weight' Type A Very C huffy Ibs. Ibs. Ib 54 47 2s 52 44.5 3s 54 43 4 - 56 44 5 - 55 44 Average 54 44.5 Type C Intermediate 6s 75 62 7b 79 62 8s 72 61 9s 73 60 10- 71 60 Average 74 61 Type D -Rangy 11s 68 58 12b 69 57 13s 69 58 14b 73 59 15b 71 58 Average 70 58 I Ibs. .500 .500 .500 .500 .500 .500 Ibs. 1.06 1.12 1.16 1.14 1.14 1.12 .562 .562 .562 .562 .562 .562 .91 .91 .92 .94 .94 .92 .562' .562 .562 .562 .562 .562 .97 .99 .97 .95 .97 .97 J s = sow; b = barrow. 2 Computed by the simple weight ratio. 1929} KXKKCiY AND PKOTKIX R KQI "IKKM KNTS OK I i KO\VI N(i S\VI.\K 539 TABLE 41. AVKH AUK KI:KI>I.\<; HE^TLTS OF THE MAINTENANCE TRIAL ox THE FAT I'K;-;: SKCOND EXPERIMENT :md sex Initial body \vt iL' Maintenance body weight Average daily feed Feed per 100 pounds body weight 1 Type A Very Chuffy Ibs. 2.20 2.50 2.26 2.32 ffo. 1.04 1 . 05 1.04 1.04 Ibs. />>*. 10s 217 211 12- 242 239 14b 221 218 Average 240 233 Type C Intermediate 6- 223 228 8b 260 263 11- 240 242 14b L'tl 237 Average 241 242 Type D Rangy 4b 269 268 7s 229 226 12- 243 241 18b 218 219 19b 256 250 Average 243 241 Computed by the simple weight ratio. cases as late as August 25, it was found that in October, when the weather became cold and an epidemic of respiratory infection involved practically all the pigs, their weights decreased on amounts of feed sufficient for maintenance during the warmer season. Hence for some of these pigs constant weight was maintained for only four or five weeks. The average data for the two maintenance feeding trials are given in Tables 40 and 41. The results of these feeding trials indicate, in agreement with the results obtained the preceding year, that the Intermediate-type pigs required less feed for the maintenance of body weight than did the piys of the other types, probably because of a smaller degree of activity. The pigs of the Rangy type rank next in this respect, while the Very ( 'huffy pigs, like the Chuffy pigs of the preceding year, were the least economical. Changes in Composition of Young Maintenance Pigs. Feeding trials alone, however, cannot give reliable information of maintenance energy requirements because, altho body weight is maintained, the 2.23 2.64 2.40 2.66 2.46 .98 1.00 1.08 1.01 2.76 2.42 2.43 2.28 2.63 2.50 1.03 1.07 1.01 1.04 1.05 1.04 540 BULLETIN Xo. 3- energy stored in the body may be considerably diminished. In the first experiment information on this point was obtained by slaughter- ing the maintenance pigs at the end of their period of experimental feeding and examining the carcasses by chemical methods. A com- parison of the composition of these carcasses with that of the control pigs revealed surprisingly large losses of energy during the period of maintenance feeding. The maintenance trials of the second experi- ment were also planned to include such examinations of the carcasses of the maintenance pigs, but unfortunately it was not found to be expedient to carry out this work on the young maintenance pigs be- cause of the prevalence of respiratory infection during October. Their feeding trials, therefore, altho remarkably uniform in the results obtained, cannot be used in the estimation of the true maintenance requirements. Attention may be called, however, to the remarkably good agreement between the results shown in Table 40 and those given in Table 7. relating to the young maintenance pigs of the pre- ceding experiment. Changes in Composition of Fat Maintenance Pigs. The '2'2'i- pound maintenance pi-.- slaughtered and analyzed according to the routine explained above as applying to all pigs in the second ex- TABLE 42. LIVE WEIGHTS AND EMPTY WEIGHTS OF THE FAT MAINTENANCE PIGS AND WEIGHTS OF FILL: SECOND EXPERIMENT Pig Live weight aht of fill Empty weight Percent of fill Type A Very Chuffy - Ibs. 209.4 to. 95.0 tot. 4.0 /6s. 20.V 4 kgs. 93.2 1.9 14 ' _ 208.5 94.6 2.7 Average 211.8 96.1 4.9 207.0 93.9 2.3 Type C Intermediate 234 6 106.4 4.7 229.9 104.3 2.0 . : 258. 1 117.1 3.5 254.6 115.5 1.4 - - - 110.5 7.0 236.7 107.4 2.9 U . . 23S.3 108.1 8.7 229.6 104.1 3.7 Average i 243.7 110.5 6.0 237.7 107.8 2.5 Type D Rangy - 270.8 188.8 - - 263.3 119.4 2.8 7 __- 103.2 9.7 217.9 98.8 4.2 12 236.4 107.2 12.0 224.4 101.8 .5.1 18 214.1 97.1 6.1 208.0 94.3 2.8 251.6 114.1 8.7 242.9 110.2 3.5 Average 240.1 108.9 8.8 231.3 104.9 3.7 EXEHGY AXD PROTEIN REQUIREMEXTS or GROWING S 541 TAB: .-.IGHTS OF PARTS OF CARCASSES OF THE FAT MAINTENANCE : SECOXB EXPEBIMEXT Pig Offal Dressed carcass Lean Fat Skin Boue Total Type A Very Chuffy : -.4 <: 9.37 10.03 9.70 t 3* >s> 39.72 39.30 ks*- 25. SO 2v54 27.18 iv*. 3.54 3.84 3.70 *- 8.00 9.74 8.88 *V- 76.22 81.84 79.04 Average in percent (49.7) (34.4 4 r 1 (100.00) Type C Intermediate - 11.59 40.36 31.92 4.02 S.82 &5.12 > 11.48 47.60 34.fc 4.14 11.56 97. 9S 12.16 44.26 32.78 3.84 10.64 91.52 11.91 41.12 2s. 14 6. IS 12.58 S3. 02 11.79 43.34 31.S.S 4.54 10.90 90.66 Average in percent . (100.00) Type D Rangy i 11.76 7 .i 11.12 45.60 -- - 19.34 5.14 5.98 12.66 12.94 91. 4 83.86 13.09 41.92 28.46 4.22 11. OS S5.6S 10.86 36.40 2S.96 4.18 1O.44 79. 9S ' 13.06 2*. 96 5.74 . -. 95.66 Average . 1 1 . 9S 44.28 26. 1O 5.06 11.96 87.40 Averagein percent ! X50.7 . r (100.00) periment. The essential weights and chemical data are given in Tables 42 to 46. Because of their relative insignificance, only the average analyses of the offal samples for the three types of pL reported. The marked difference in ''fill'' between the fat pi. _hing about 225 pounds that were taken directly from full feed and those that were taken from a maintenance ration is of interest. The average fill of the full-fed pigs was 12.1 pounds and for the maintenance pigs, 7.1 pounds. omparison of the percentage composition of the 225-pound pigs killed at the end of their fattening period and those killed after a maintenance period of two or three months does not reveal the large differences noted in the preceding year. For convenience of study the average- composition of the dressed carcass, offal, and entire body of the three types and the two groups of pigs are summarized in Table 47. 542 BULLETIN No. 323 [May, TABLE 44. PERCENTAGE COMPOSITION AND ENERGY CONTEXT OF DRESSED CAR- CASSES OF THE FAT MAINTENANCE Pios: 1 SECOND EXPERIMENT Pig No. Dry substance Crude protein (Nx6.0) Fat Ash Gross energy per gram Type A Very Chuffy pet. pet. pet. 10 61.13 13.02 41.09 14 59.40 11.88 44. 4S Average 60.26 12.45 42.79 Type C Intermediate 6 61-69 11.16 47.51 8 59.13 12.06 43.88 11 61-00 11.64 45.76 14 56-11 12.66 40.10 Average 59.48 11.88 44.31 Type D Rangy 4 57.62 12.84 40.92 7 51.91 13.20 33.97 12 57.34 11.94 41.64 18 61.89 11.82 46.50 19 55.98 12.42 40.33 Average 56.95 12.44 40.67 pet. 3.15 2.83 2.99 sm. cols. 4 469 4 810 4 640 2.88 2.93 2.74 3.28 2.96 5 015 4 774 5 809 4 433 4 758 3.29 3.7o 3.12 2.66 3.05 3.18 4 444 3 929 4 713 4 998 4 334 4 484 'Corrected. Except for a general increase in the ash content and a prevailing increase in protein, the composition of the fat maintenance pigs was quite similar to that of the fat pigs. In particular this similarity holds for the gross energy content, the differences indicated in the table being such as would be expected from the statistical "error of sampling" alone. Possibly a partial explanation of the absence of marked differences in the fat and energy content of the fat maintenance pigs and of the fat pigs weighing 225 pounds may be found in the fact that in several cases the maintenance pigs were not put upon the maintenance ration TABLE 45. AVERAGE PERCENTAGE COMPOSITION OF OFFAL SAMPLES OF THE FAT MAINTENANCE PIGS: SECOND EXPERIMENT Dry substance Crude protein (Nx6.0) Fat Ash Gross energy per gram Type A. TypeC. Type D. pet. 30.37 34.15 33.37 pet. 13.14 12.66 12.47 pet. 14.62 18.97 18.45 pet. 1.00 .83 .96 sm. cala. 2 289 2 573 2 393 1929] ENERGY AND PROTEIN REQUIREMENTS OF GROWING SWINE 543 TABLE 46. PERCENTAGE COMPOSITION OF THE FAT MAINTENANCE PIGS, ON LIVE-WEIGHT BASIS: SECOND EXPERIMENT Pig No. Dry substance Crude protein (NxG.O) Fat Type A Very Chuffy Ash Gross energy per gram pet. pet. pet. 10 51.87 11.88 34.09 14 53.61 11.48 39.29 Average 52.74 11.68 36.69 Type C Intermediate 6 53.05 10.41 39.85 8 52. (2 11.48 38.33 11 55.21 11.06 40.86 14 49.29 11.89 34.36 Average 52.54 11.21 38.35 Type D Rangy 4 46.28 10.90 32.14 7 45.59 12.30 29.07 12 50.29 11.09 35.84 18 55.25 11.16 41.05 19 50.73 11.94 35.77 Average 49.63 11.48 34.77 pet. 2.63 2.51 2.57 STO. Cols. 3 782 4 331 4 057 2.40 2.54 2.37 2.78 2.52 4 277 4 228 4 347 3 875 4 182 2.56 3.18 2.62 2,32 2.66 2.67 3 539 3 428 4 090 4 444 3 890 3 878 at the end of their fattening period; with some pigs several weeks intervened. In this interim considerable weight was put on, particu- larly by Pig 8 of the Intermediate type and Pigs 4 and 19 of the Rangy type and to a less extent by Pigs 11 and 14 of the Intermediate type and Pig 12 of the Rangy type. In these cases, therefore, it is questionable whether comparison with the 225-pound fat pigs is significant. Estimates of Feed Required for Maintenance. Correction of the feed records of the fat maintenance pigs for the indicated changes in the energy content of their bodies (Table 47) in a manner similar to that used for the maintenance pigs of the preceding experiment (Table 19) yields the estimates in Table 48. The average daily feed requirements per 100 pounds body weight for the three types were 1.11, .93, and .95 pounds respectively, as compared with 1.21, .98, and 1.23 pounds for the Chuffy, Intermediate, and Rangy pigs in the pre- ceding experiment (Table 19). Considering the Very Chuffy and Chuffy types as comparable in their feed requirements per unit of weight, the agreement between the two experiments is good except for the Rangy type. The fact that the computations for the Rangy pigs from the data of the second experiment may be faulty, as explained 544 BULLETIN No. 323 [May, TABLE 47. COMPARISON OF AVERAGE PERCENTAGE COMPOSITION OF THE 225- POUND FAT PIGS AND OF THE FAT MAINTENANCE PIGS: SECOND EXPERIMENT Dry substance Crude protein (Nx6.0) Fat Ash Gross energy per gram Type A Very Chuffy pet. pet. pet. pet. am. eels. Dressed carcass Fat pigs 62.24 9.93 49.21 2.21 4 956 Maintenance pigs .... 60.26 12.45 42.79 2.99 4 640 Offal Fat pigs . . . 31.50 12.45 15.41 .83 2 288 Maintenance pigs .... 30.37 13.14 14.62 1.00 2 289 Live pig Fat pigs 51.59 9.37 39.40 1.80 4 070 Maintenance pigs .... 52.74 11.68 36.69 2.57 4 057 Type C Intermediate Dressed carcass Fat pigs 60.64 11.60 45. 10 2 72 4 830 Maintenance pigs. . . . 59.48 11.88 44.31 2.96 4 758 Offal Fat pigs 31.51 12.53 16 22 89 2 253 Maintenance pigs .... 34.15 12.66 18.97 .83 2 573 Live pig Fat pigs 51.39 10.89 37.09 2.24 4 053 Maintenance pigs .... 52.54 11.21 38.35 2.52 4 182 Type D Rangy Dressed carcass Fat pigs 55.94 12 32 40 23 2 73 4 422 Maintenance pigs .... 56.95 12.44 40.67 3.18 4 484 Offal Fat pigs 29.10 12.98 14 42 91 2 083 Maintenance pigs .... 33.37 12.47 18.85 .96 2 393 Live pig 47 45 11 57 33 00 2 24 3 710 Maintenance pigs .... 49.63 11.48 34.77 2.67 3 878 above, may account for this discrepancy. Also the fact that in this experiment only two of the fat maintenance pigs of the Very Chuffy type were slaughtered 1 detracts from the significance of the average estimate of this type. It seems evident, therefore, that the maintenance experiments of the second type were much less successful than those of the first year. 1 Pig 12 of the Very Chuffy type became sick, lost in weight, and was removed from the experiment. 1929] ENERGY AND PROTEIN REQUIREMENTS OF GROWING SWINE 545 TABLE 48. CORRECTED FKKD REQUIREMENTS OF THE FAT MAINTENANCE PK;S: SECOND KXPEKIMENT Maintenance Peed feed per day Initial Average Initial Final Loss Total erjui va- Main- Pig No. weight weight energy energy of f 1 lent of tenance Per 100 content content energy eaten energy loss 1 period Total pounds body weight- Type A Very Chuffy 10 Ibs. 217 it*. 212 tin rutfi 400 therms 359 tin r /;/." 41 Iba, 145 Ibs. 31 day* 66 Ibs. 2.67 Iba. 1 L'li 14 . . 221 218 408 421 -13 149 10 66 2 11 97 Average. . . . 215 404 390 14 1.11 Type C Intermediate 6. . . 223 228 410 455 -45 194 34 87 1 84 81 8 260 282 478 495 17 230 13 87 2 49 05 11 240 242 439 480 41 132 31 1 si .76 14. . 241 237 443 419 24 187 18 73 2 81 1 19 Average. . . . 242 442 462 -20 .93 Type D Rangy 4 269 268 453 435 18 240 14 87 2 60 97 7. . . 229 226 385 354 31 177 23 73 2.74 1.21 12. . . 243 241 409 438 29 134 22 55 2 00 83 18 218 219 367 431 64 166 48 73 1 62 74 19 256 250 427 444 -17 192 13 73 2 45 .98 Average. . . . 241 408 420 -12 .95 'Assuming that the nietabolizable energy of the ration, 1,331 calories per pound, is completely utilizable. 'Using the ratio of body weights. Since the rations of the two series of experiments were quite similar, the estimates of the feed requirements for maintenance obtained in the first year's work, rather than the incomplete maintenance esti- mates of the second year, will be used in computations of the utiliza- tion of feed energy by the fat pigs weighing 225 pounds. It is not believed that the application of the estimated requirements of the ('huffy pigs to the Very Chuffy pigs of this experiment will result in serious error. Digestibility and Metabolizable Energy of the Maintenance Ra- tion. During the period of maintenance feeding 9 of the young pigs and 8 of the fat pigs w r ere subjected to digestibility studies in which, besides the chemical examination of feed and feces, the gross energy- content of feed, feces, and urine was also determined, thus permitting the computation of metabolizable energy. The nitrogen content of 546 BULLETIN No. 323 [May, TABLE 49. COEFFICIENTS OF DIGESTIBILITY OBTAINED WITH THE YOUNG MAIN- TENANCE PIGS: SECOND EXPERIMENT Pig No. Dry substance Crude protein N-free extract Crude fiber Fat Type A Very Chuffy 2 pet. 67 75 75 pet. 60 69 59 pet. 84 91 87 pet. 13 28 14 pet. 67 71 63 1 3 Type C Intermediate 6 . 74 68 70 68 65 64 87 82 91 -11 -11 -33 80 57 77 7 8 Type D Rangy 13 80 52 65 69.6 71 68 61 65.0 90 84 83 86.6 33 -25 -11 Q 80 71 67 70.3 1.5 14 Average the urine was also determined, so -that estimates of nitrogen balances and corrections of metabolizable energy to a condition of nitrogen equilibrium could be made. The collection periods in all cases were of ten days' duration. The periods of preliminary feeding were several weeks in length. TABLE 50. COEFFICIENTS OF DIGESTIBILITY OBTAINED WITH THE FAT MAINTE- NANCE PIGS: SECOND EXPERIMENT Pig No. Dry substance Crude protein N-free extract Crude fiber Fat Type A Very Chuffy 10 . pet. 84 85 pet. 76 79 pet. 90 92 pet. 51 50 pet. 81 63 14 Type C Intermediate 14 .. 80 84 76 78 88 89 9 43 66 79 8 Type D Rangy 7 79 83 84 85 83.3 73 79 80 79 77.6 85 89 90 91 89.6 5 12 40 39 33.3 67 74 76 66 71.9 19 18 4 Average EXERGY AND PROTEIN REQUIREMENTS OF GROWING SwiNE 547 TABLE 51. AVERAGE DAILY NITROGEN BALANCES OF THE YOUNG MAINTENANCE PIGS: SECOND EXPERIMENT Pig No. Nitrogen of feed consumed Nitrogen of f> ces Nitrogen of urine Nitrogen balance Type A Very Chuffy 2 grams 4.80 4.64 4.64 grams 1.92 1.44 1.92 grams 3.53 3.14 2.56 grams .35 .06 .16 1 3 Type C Intermediate 6 5.44 5.44 5.28 1.76 1.92 1.92 3.03 2.93 3.47 .65 .59 - .11 7 8 Type D Rangy 13 :, . 44 5.44 5.28 1.60 1 . 70 2.08 3.14 3.14 3.70 .70 .54 - .50 .27 15 14 Average The heavier maintenance pigs utilized their feed better than the young pigs mainly because of a higher digestibility of protein, which in the former case ayeraged 77.6 percent and in the latter 65.0 (Tables 49 and 50). The heavier pigs also appeared to use the crude fiber more efficiently than the lighter pigs. The young maintenance pigs TABLE 52. AVERAGE DAILY NITROGEN BALANCES OF THE FAT MAINTENANCE PIGS: SECOND EXPERIMENT Pig No. Nitrogen of feed consumed Nitrogen of feces Nitrogen of urine Nitrogen balance Type A Very Chuffy 10 grams 22.08 21.12 grams 5.28 4.48 grams 11.60 12.62 grams 5.20 4.02 14 Type C Intermediate 14 24.16 26.24 5.92 5.76 13.50 16.61 4.74 3.87 8 Type D Rangy 7 22.88 24.64 22.88 25.76 6.08 5.12 4.64 5.28 8.69 16.61 17.38 15.77 8.11 2.91 .86 4.71 4.30 19 18 4 Average > v . - : . :.:;. . :M - - - - - - - 550 BULLETIN No. 323 were storing nitrogen at the average rate of .27 gram per day and the fat maintenance pigs, at the average rate of 4.30 grams per day (Tables 51 and 52). For the young pigs the metabolizable energy per kilogram of dry matter eaten averaged 3.29 therms and per pound of digestible organic matter, 1.94 therms (Table 53). For the fat pigs these averages were, in order, 3.44 and 1.89 therms (Table 54) . An average of 73.2 percent of the gross energy of the feed was metabolizable for the young pigs and 79.4 percent for the fat pigs. Metabolizable Energy Required for Maintenance. If it is per- missible to combine the feeding data relating to maintenance require- ments of the first year's experiment with the determinations of the metabolizable energy of the feed obtained in the second year's work, an estimate of the amount of metabolizable energy required for the maintenance of the energy equilibrium of swine may be made. The ration used in the first maintenance trial contained approxi- mately 90 percent of dry matter. On the assumption that the metabo- lizable energy content was 3.36 therms per kilogram of dry matter, which is equal to 1.525 therms per pound, the young maintenance pigs appeared to need an average of 2.031 calories of metabolizable energy per day per 100 pounds live weight (weight ratio), while the fat pigs required an average of 1,551 calories (Table 55). Armsby 1 has com- TABLE 55.- -METABOLIZABLE ENERGY REQUIRED FOR MAINTENANCE OF SWINE PER 100 POUNDS LIVE WEIGHT PER DAY 50-pound pigs L'-'Vpound piga Type Feed Metabolizable energy Type Feed Metabolizable energy B .... H>. 1.62 1.44 1.39 1.48 cols. 2 223 1 976 1 908 2 031 B.. . . .... Ibs. 1.21 .98 1.23 1.13 cals. I 661 1 315 1 688 1 551 c C D D . Average Average puted from the results of live-weight experiments that swine need some 1.534 calories of metabolizable energy per day per 100 pounds live weight for maintenance, altho a wide range of estimates were obtained from individual experiments. This estimate of Armsby 's is in close agreement with the average obtained in this experiment for the older swine, which weighed approximately 225 pounds. The young pig appears to require, per unit of weight, a considerably larger amount of energy, approximately one third more. 1 Armsby. H. P. The nutrition of farm animals, 287. 1929} EXKRGY AND PUOTEIN REQUIREMENTS OF GROWING SWINE 551 THE FATTENING EXPERIMENT The fattening experiment involved 60 pigs, 20 from each of the Very (.'huffy, Intermediate, and Rangy types. These pigs were put upon experimental feeding individually as they reached the desired initial weights, that is, 55 pounds for the Very Chuffy type and 70 pounds for the Intermediate and Rangy types. The pigs that were started first on June 30 included some pigs that were slightly heavier than these weights. The remaining pigs were put on experiment dur- ing July, with the exception of Pig 16 of the Very Chuffy group, which was started on August 4. The ration used consisted of mixtures of shelled corn, tankage, middlings, and alfalfa meal varied according to the weights of the pigs. The corn was fed whole and the other feeds in a mixture con- sisting of 8 parts of middlings, 4 parts of tankage, and 1 part of alfalfa meal. The ratio of corn to mixture was changed according to a definite plan as the pigs increased in size. TABLE 56. LIVE AND EMPTY WEIGHTS AND "FILL" OF THE PIGS KILLED AT APPROXIMATELY 175 POUNDS: SECOND EXPERIMENT Pig No. and sex 1 Date of daughter Live weight Weight of contents of alimentary tract Empty weight Contents of alimentary tract in percent of live weight Type A Very Chuffy 6b \ov 26, 1923 . 168.88 kgs. 76.60 Ibs. 8.63 ibs: 160.25 kgs. 72.69 pet. 5.11 9s Nov. 26, 1923 183.81 83.37 9.94 173.88 78.87 5.40 16s . . Dec. 20, 1923 190.69 86.50 6.88 183.81 83.37 3.61 18b Nov. 20, 1923 178.94 81.17 10.19 168.75 76.54 5.69 19b Nov 26, 1923 178.88 81.14 20s ... Nov. 26, 1923 167.00 75.75 8.69 158.31 71.81 5.20 Avp-a -P 178.03 80. '6 8.87 109.00 76. 61 5.03 Type C Intermediate 3s Nov. 1, 1923 183.63 83.29 10.25 173.38 78.64 5.58 Oct. 11, 1923 170.88 77.51 14.31 156.56 71.01 8.37 13b Oct. 1, 1923 182.56 82.81 14.38 168.19 76.29 7.88 Average 179.02 81.20 12.98 166.04 75.31 7.28 Type D Rangy 14b Oct. 1, 1923 169.88 77.06 12.94 156.94 71.19 7.62 lob Nov 14, 1923 188. 19 85.36 12.25 175.94 79.80 6.51 20b Oct. 1. 1923 174.94 79.35 13.19 161.75 73.37 7.54 Average 177.67 80.59 12.79 164.88 74.79 7.22 '8 = sow; b = barrow. 552 BULLETIN No. 323 [Hay, It was the original plan of the experiment to kill five pigs from each type at a Aveight of approximately 175 pounds, five at a weight of approximately 225 pounds, and five at a Aveight of approximately 275 pounds, the remaining five pigs to be used at a weight of about 225 pounds in a maintenance feeding trial. HoAveA r er, during the months of October and November, as Avith the first experiment, an epidemic of respiratory infection destroyed several of the pigs, and because of this and other unforseen contingencies the above plan was not adhered to. Composition of Pigs Slaughtered at 175 Pounds. Twelve pigs Avere slaughtered at weights approximating 175 pounds, 6 from the Very Chuff y type and 3 each from the other tAvo types. The dates of slaughter, live, and empty weights, and the Aveights and percentages of "fill" for these pigs are collected in Table 56. The average per- TABLE 57. WEIGHTS OF SAMPLES AND PHYSICAL COMPOSITION OF DRESSED CAR- CASSES OF THE 175-POUND PlGSI SECOND EXPERIMENT Pig No. Offal Dressed carcass Lean Fat Skin Bone Total Type A Very Ohuffy 6 kgs. 10.25 kgs. 29.42 kgs. 18.76 kgs. 3.04 kgs. 7.20 kgs. 58.42 9 11.23 29.78 23 . 78 3.02 7.38 63 . 96 16 10 7."> 29 34 28 54 2 78 6 56 67 22 IS. 10.88 27.68 22.96 3.06 7.80 61.50 19 9.51 29.02 24.42 3.08 6.70 63 . 22 20 9 53 26.80 22.50 2.92 6.58 58.80 10.36 28.68 23.50 2.98 7.04 62. IS Average in percent (46.1) (37.8) (4.8) (11.3) (100.0) Type C Intermediate 9 28 28 86 25.30 3.26 7.20 64.62 5 10.82 25.38 20.26 4.28 7.84 57.76 13 .... 11.06 28.92 19.86 4.24 8.82 61.84 10.39 27.72 21.80 3.92 7.96 61.40 Average in percent (45.1) (35.5) (6.4) (13.0) (100.0) Type D Rangy 14 10.73 24.98 21.78 3.74 7.42 57.92 15 11.24 32.44 18.80 4.14 9.12 64.50 20 11.54 25 52 20.66 4.06 7.78 58.02 27.64 20.42 3.98 8.10 60.14 Average in percent (46.0) (34.0) (6.6) (13.5) (100.0) 19H9] ENERGY AND PROTEIN OK GROWING SWINE 553 centage fill for the Very ('huffy piu> \\.-is 5.0, for the Intermediate pigs 7.3, and for the Kan try pigs 1:2. On the average the dressed carcasses from the Very ('huffy pigs contained a larger percentage of separable fat (37.8) than those of the other typrs (35.5 and :>4.0, in order) and a smaller percentage of skin i, 4>. as compared with (i.4 and 6.6) and bone (11.3 as com- pared with 13.0 and 13.5) (Table 57). The percentage composition of the dressed carcasses, as determined by chemical analysis (Table 58), was not, however, significantly different for the different types except possibly with reference to ash. In fat and energy content the three types of carcasses are not to be certainly distinguished, tho in general the Very ('huffy pi^s rank the highest in these respects. They appear to be significantly lower in ash than the dressed carcasses of either the Intermediate or the Rangy plus. The average percentage composition of the offal samples only is given in Table 59. The percentage composition of the entire carcasses on the live-weight basis (Table 60) shows the same general relations among the three types as that of the dressed carcasses. TABLE 58. PERCENTAGE COMPOSITION OF DRESSED CARCASSES OF THE 175-PouND PIGS: SECOND EXPERIMENT Pit: I Dry gubet Crude protein \ V Aflh Gross energy per gram Type A Very CliufTy pet. 56.86 pet. 10.26 pet. 42 94 pet. " . in 4 583 9 54 96 11 94 39 34 3 13 4 17."> 16 60.43 11.22 47.07 2.10 5 025 18 57.73 12.18 42 64 ' 7" 4 660 19 56 59 12 06 4'' 'it ' 7H 4 810 20 59.27 11.64 43.58 3.11 4 665 Average 57.64 11.55 43.04 2.67 4 703 Type C Intermediate 3 54.28 12.78 37.58 3 43 4 257 5 58 89 12 24 42 17 3 20 4 532 13 57 93 12 60 39 63 3 21 4 273 r e 57.03 12.54 39.79 3.28 4 354 Type D Rangy 14 57 67 11 88 42 72 3 15 4 626 15 55 77 12 42 39 20 3 15 4 411 20 60 71 11 88 42 38 3 13 4 517 Average. 58 05 12 06 41 43 3 14 4 518 Average of all types 57.59 11.92 41.82 2.94 4 569 554 BULLETIN No. 323 [May, II 111 II BBSS! FIG. 3. REPRESENTATIVE CARCASSES OF VERY CHUFFY, INTERMEDIATE, AND RANGY PIGS SLAUGHTERED AT APPROXIMATELY 175 POUNDS LIVE WEIGHT: SECOND EXPERIMENT The Very Chuffy carcass contained a larger percentage of separable fat and a smaller percentage of skin and bone than the other carcasses. The results of chemical analysis of these carcasses were not significantly different for the three types except possibly with reference to ash. On the empty-weight basis the average percentages of dry substance for the three type groups were 51.1, 50.8, and 51.3 respectively; the average percentages of crude protein were 11.4, 12.3, and 11.9, of fat 36.8, 34.2, and 35.4, and of ash 2.3, 2.8, and 2.7 ; the average amounts of gross energy per gram of empty carcass were 4.12, 3.84, and 3.95 calories. Composition of Gains up to a Weight of 175 Pounds. Applying the average percentage composition of the control pigs (Table 38) of the three types to initial weights of 55 pounds for the Very Chuffy type and 70 pounds for the Intermediate and Rangy types, and the average percentage composition of the pigs killed at approximately 175 pounds to an exact weight of 175 pounds, will give the weights of nutrients in pigs of these weights. Subtracting the estimated ENERGY AND PROTEIN REQUIREMENTS OF GROWING SWINE 555 TABLE 59 AVERAGE PERCENTAGE COMPOSITION AND ENERGY CONTENT OF OFFAL SAMPLES FOR EACH TYPE FOR THE 175-PouND PIGS: SECOND EXPERIMENT Dry substance Crude protein (Nx6.0) Fat Ash Gross energy per gram Type A pet. 29.22 pet. 12.69 pet 14.28 pet. 1.03 sm. cols. 2 107 TvpeC.. . 28.39 12.54 12.38 .88 1 964 Type D 28.57 12.26 14.20 1.00 2 012 weights of nutrients in the 55-pound and 70-pound pigs from the esti- mated weights in the 175-pound pigs of like type will give estimates of the gains in nutrients between these live weights. The percentage composition of these gains is obtained by dividing the weights of added nutrients by the corresponding gains in live weight, namely, 120 pounds for the pigs of the Very Chuffy type and 105 pounds for the pigs of the other types. It seems unnecessary to report the intermediate calculations lead- ing to the estimated percentage composition of gains. The Very TABLE 60. PERCENTAGE COMPOSITION AND GROSS ENERGY CONTENT OF THE 175- POUND PIGS ON BASIS OF LIVE WEIGHT: SECOND EXPERIMENT Pig No. Dry substance Crude protein (Xx6.0) Fat Ash Gross energy per gram Type A Very Chuffy 6 . pet. 47.58 pet, 10.10 pet. 34.48 pet. 1.85 sm. cols. 3 780 9 46.29 11.16 32.09 2.55 3 725 16 51.06 10.53 38.38 1.80 4 194 18 . 48.26 11.16 34.56 2.21 3 854 19 47.94 11.25 35.04 2.27 4 023 20 49.93 10.94 35.37 2.60 3 892 Average 48.51 10.86 34.99 2.21 3 911 Type C Intermediate 3 45.70 48.42 47.17 47.10 11.73 11.08 11.42 11.41 30.47 33.45 31.06 31.66 2.80 2.52 2.54 2.62 3 539 3 699 3 449 3 562 5. .. 13 Average Type D Rangy 14 47.31 11 08 33 82 2 53 3 753 15 46.54 11.29 31.63 2.57 3 624 20 49.02 10.75 33 21 2 44 3 632 Average 47.62 11.04 32.89 2.51 3 670 556 BULLETIN >Co. 323 [May, Chuffy pigs in gaining from 55 to 175 pounds put on added weight containing 54.3 percent of dry matter, 10.2 percent of crude protein (Xx 6.0), 42.0 of fat, and 2.1 of ash, and possessing a gross energy value of 2.05 therms per pound. The gain of the Intermediate pigs from 70 to 175 pounds live weight contained 52.6 percent of dry matter, 11.3 percent of crude protein, 37.7 percent of fat, 2.9 percent of ash, and 1.85 therms of gross energy per pound. The gain of the Rangy pigs thru the same weight interval contained 53.9 percent of TABLE 61. LIVE AND EMPTY WEIGHTS AND "FILL" OF THE PIGS KILLED AT AP- PROXIMATELY 225 POUNDS: SECOND EXPERIMENT Pig No. and sex 1 Date of slaughter Live weight Weights of contents of alimentary tract Empty weight Contents of alimentary tract in percent of live weight Type A Very Chuffy lib Dec 20, 1923 Ibs. 226.1 kgs. 102.5 Ibs. 13. 2 1 Ibs 212 8 kgs. 96 5 pet. 5 9 Jan. 3, 1924 234.8 106.5 16.5 218.3 99.0 7.0 Average 230.4 104.5 14.9 215.6 97.8 6.4 Type C Intermediate: Hand-fed Ib Jan. 3, 1924 218.6 99.2 6.7 211.9 96.1 3 1 2b Dec 10, 1923 228.2 10J.5 7 4 220.8 100.2 3 3 9b Nov 8 1923 224 101.6 13 4 210 6 95 5 6 15b Nov 20, 1923 224.4 101.8 12.3 212. 1 96.2 5.5 18s Nov 8, 1923 239.2 108.5 12.2 226.9 102.9 5 1 19b Nov 26, 1923 223.8 101.5 12 1 211 7 96 ,~i 4 Average 226.4 102.7 10.7 215.7 97.8 4.7 Type C Intermediate: Self-fed 60s Oct. 16, 1923 Oct. 11, 1923 Nov. 20, 1923 Nov. 20, 1923 Oct. 16, 1923 210.4 217.0 217.0 219.1 230.9 218.9 95.4 98.4 98.4 99.4 104.7 99.3 90s 91s 99s .. 99b Average Type D -Rangy 2b Dec. 10, 1923 Dec. 20, 1923 Nov. 26, 1923 Nov. 14, 1923 Nov. 14, 1923 221.1 232.4 219.9 228.4 225.3 225.4 100.3 105.4 99.8 103.6 102.2 102.2 7.7 14.9 17.8 12.2 11.1 12.7 213.4 217.5 202.1 216.1 214.2 212.7 96.8 98.7 91.7 98.0 97.2 96.5 3.5 6.4 8.1 5.4 4.9 5.6 5b 8b 9s 16b Average 's = sow; b = barrow. 2 Not weighed. Average for A, C, and D types. 19 '29} ENERGY AND PKOTEIN RKQnnr.MKNTs OF GROWING SWINE 557 dry matter. 10.4 percent of protein, 40.3 percent of fat. 2.6 percent of ash. and 1.94 therms of gross energy per pound. Composition of Pigs Slaughtered at 225 Pounds. Two pin- tin- Very ('huffy type. 6 of the Intermediate, and 5 of the Rangy were slaughtered at a weight of 225 pounds. In addition 5 Intermediate pigs that had been self-fed in a group of 10 on the same ration as the hand-fed pigs were also slaughtered at this weight. These pigs, probably because of the competition accompanying lot feeding, had FIG. 4. REPRESENTATIVE CARCASSES OF VERY CHUFFY, INTERMEDIATE. AND RANGY PIGS SLAUGHTERED AT APPROXIMATELY 225 POUNDS LIVE WEIGHT: SECOND EXPERIMENT The dressed carcasses of the Very Chuff y pigs slaughtered at this weight wore in general higher in fat than those of the intermediate pigs, which in turn were noticeably fatter than those of the Rangy pigs. consumed more feed and had gained considerably faster than the hand-fed pigs. The results of their analyses, when compared with those for the hand-fed pigs of the same type, are of interest in con- nection with the general question of the effect of the rate of gains upon the composition of the carcass and of the gains in weight. The weights, "fills", slaughter data, and the percentage composi- tion of the dressed carcasses of these 18 pigs are presented in Tables 558 BULLETIN No. 323 [May, TABLE 62. WEIGHTS OF SAMPLES AND PHYSICAL COMPOSITION OF DRESSED CAR- CASSES OF THE 225-PouND PIGS: SECOND EXPERIMENT Pig No. Offal Carcass composite Lean Fat Skin Bone Total Type A Very Chuffy kgs. kgs. kgs. kgs. kgs. kgs. 11 12.01 33.26 35.06 3.76 6.92 79.00 17 12.62 34.28 34.52 3.86 7.98 80.64 Average. . . . 12.32 33.78 34.80 3.82 7.46 79.86 Average in percent . . (42.3) (43.6) (4.8) (9.3) (100.00) Type C Intermediate: Hand-fed 1 .... 11.34 40.34 28.64 3.60 8.34 80.92 2 14.03 31.56 37.40 4.22 9.80 82.98 9 13.05 36.88 27.60 3.80 8.06 76.34 15 13.03 35.64 28.72 3.30 9.08 76.74 18 12.77 37.62 31.98 4.38 8.40 82.38 19 12.72 36.86 29.64 3.78 8.74 79.02 Average. . . . Average in percent . . 12.82 36.48 (45.8) 30.66 (38.5) 3.84 (4.8) 8.74 (11.0) 79.72 (100.0) Type C Intermediate: Self-fed 60 13.29 26.90 32.08 4.46 6 96 70 40 90 12.44 30.82 32 88 3.46 7.48 74.64 91 12.20 38.20 29.10 3.74 7.30 78 34 99 1 13.13 28.50 36.32 4.00 7 90 76 72 99 ! 14.26 36.70 31.64 5.06 8.24 81.64 Average. . . . Average in percent . . 13.06 32.22 (42.2) 32.40 (42.4) 4.14 (5.4) 7.58 (9.9) 76.34 (100.0) Type D Rangy 2 13.85 38 34 28 54 3 84 11 16 81 88 5 15.00 36.00 30.36 3 56 11 24 81 16 8 13.98 33.16 23 58 4 66 11 76 73 16 9 13.76 38 72 26 12 4 20 9 64 78 68 16 13.06 39.14 25.56 4.22 10 06 78 98 Average. . . . Average in percent . . 13.93 37.08 (47.1) 26.84 (34.1) 4.10 (5.2) 10.78 (13.7) 78.80 (100.0) 'Sow. 'Barrow. 19X9] ENERGY AND PROTEIN REQUIREMENTS OF GROWING SWINE 559 TABLE 63. PERCENTAGE COMPOSITION OF DRESSED CARCASSES OF THE PIGS KILLED AT APPROXIMATELY 225 POUNDS: SECOND EXPERIMENT Pig No. Dry substance Crude protein (Nx6.0) Fat Ash Gross energy per gram Type A Very Chuffy 11. . pet. 60.85 63.63 62.24 pet. 10.32 9.54 9.93 pet. 47.87 50.54 49.21 pet. 2.08 2.34 2.21 am. cola. 4 624 5 287 4 956 17 \ - ... Type C Intermediate: Hand-fed 1 60.17 64.50 58.14 60.35 62.73 57.95 60.64 12.78 10.02 11.04 11.76 12.54 11.46 11.60 43.26 50.77 43.51 44.91 44.62 43.55 45.10 2.64 2.56 2.24 (3.71)' 2.57 2.59 2.52 4 784 5 349 4 628 4 811 4 716 4 694 4 830 2 9 15 18 19. ... Average Type C Intermediate: Self-fed 60 64-. 95 64.29 58.18 65.56 63.36 63.27 10.56 10.08 12.00 9.72 11.04 10.68 51.15 51.75 44.86 53.63 47.69 49.82 2.24 2.15 2.37 1.75 2.37 2.18 5 386 5 345 4 706 5 547 4 976 5 192 90 91 99* 99 s . Average Type D Rangy 2 57 71 11 82 42 00 2 59 4 571 5 57.95 11.82 42.85 2.77 4 609 8 54.52 13.16 38.18 2.69 4 159 9 55.29 12 60 39 25 2 89 4 365 16 54 24 12 18 '38 87 2 69 4 407 Average 55.94 12.32 40.23 2.73 4 422 'Omitted from the average. *Sow. 'Barrow. 61, 62, and 63. The dressed carcasses of the 2 Very Chuffy pigs were in general higher in fat than those of the 6 hand-fed Intermediate pigs, which in turn were noticeably fatter than those of the 5 pigs of the Rangy type. The self -fed pigs of the Intermediate type produced dressed carcasses rather distinctly fatter than the hand-fed pigs of the same type. The higher ash content of the dressed carcasses of the Rangy pigs is also noticeable. The offal samples of the three types showed only inconsiderable differences in percentage composition. 560 BULLETIN No. 323 [May, TABLE 64. AVERAGE PERCENTAGE COMPOSITION OF OFFAL SAMPLES OF THE 225- POUND PIGS: SECOND EXPERIMENT Type Crude protein (Nx6.0) Fat Ash Gross energy per gram A C, hand-fed . C, self-fed... D.. . pet. 31.50 31.51 31.26 29.10 pet. 12.45 12.53 12.25 12.98 pet. 15.41 16.22 16.04 14.42 pet. .83 .91 sm. cats. 2 288 2 253 2 349 2 083 TABLE 65. PERCENTAGE COMPOSITION AND GROSS ENERGY CONTENT OF THE 225- POUND PIGS ON BASIS OF LIVE WEIGHT: SECOND EXPERIMENT Pig No. Dry substance Crude protein (NxG.O) Fat Ash Type A Very Chuffy pet. pet. pet. 11 51.13 9.72 38.94 17 52.05 9.01 39.86 ,\vr>ra<*p 51.59 9.37 39.40 Typ3 C Intermediate: Hand-fed 1 53.04 12.17 37.08 2 55.78 10.18 42.35 9 48.37 10.17 35.11 15 50.35 10.70 36.31 18 51.46 11.30 35.73 19 49.33 10.82 35.96 Average 51.39 10.89 37.09 Type C Intermediate: Self-fed 60 52.43 9.80 39.94 90 52.14 9.34 40.45 91 50.47 11.43 37.57 99' 52.88 9.17 41.56 99* 54.34 10.49 39.97 Average 52.45 10.05 39.90 Type D Rangy 2 51.59 11.72 36.30 :> 49.24 11.08 35.23 8 44.23 12.23 ' 29.81 9 46.28 11.47 31.84 16 45.91 11.33 31.84 Average 47.45 11.57 33.00 pet. 1.72 1.88 1.80 sm. Cain. 3 864 4 275 4 070 2.28 2.18 1.82 2.92 2.08 2.14 2.24 4 180 4 571 3 807 3 974 3 843 3 941 4 053 1.77 1.73 2.00 1.44 2.03 1.79 291 279 039 4 472 4 238 4 264 2.25 2.28 2.11 2.35 2.22 2.24 4 027 3 882 3 344 3 611 3 688 3 710 'Sow. 'Harrow. W89] ENERGY AND PROTEIN REQUIREMENTS OK GROWING SWINE 561 TABLE 66. LIVE AND EMPTY WKKJHTS AND "FILL" OF THE PIGS KILLED AT AP- PROXIMATELY 275 POUNDS: SECOND KXPKKIMENT Pig No and sex Date of slaughter Live weight Weight of contents of alimentary tract Empty weight Contents of alimentary tract in per cent of live weight Type A Very ChufTy 5s Feb. 26, 1924 Ibs. 276.4 kgs. 1 ->.-> . 4 Ib*. 10.7 Ibs. 265.7 kgs. 120.5 pet. 3.9 Type C Intermediate 10s Feb. 1, 1924 Dec 10, 1923 Dee. 20, 1923 Jan. 3, 1924 283.9 279.1 276.8 285.8 281.3 128.8 L26.6 126.4 129.6 127.6 6.3 10.7 12.7 13.4 10.8 277.6 268.4 263.7 272.4 270.5 125.9 121.8 119.6 123.6 122.7 2.2 3.8 4.6 4.7 3.8 12b 16b 17b Average . . . Type D Rangy Is Jan 8, 1924 267.7 121.4 6.9 260.8 118.3 2.6 3b Jan 8, 1924 271. 1 123.0 10.4 260.7 118.2 3.8 Ob Jan 8 1924 280 2 127 1 12 8 267 8 121.5 4.4 lOb Jan 8, 1924 275.6 125.0 11.8 263.8 119.7 4.3 13b Average. . . Dec. 10, 1923 269.0 272.7 122.0 123.7 11.5 10.6 257.5 262.1 116.8 118.9 4.3 3.9 The estimated percentage composition of the 225-pound pigs on the basis of the live weight will be found in Table 65. Since these values are mainly determined by the composition of the dressed car- casses, they do not require any special discussion. On the empty-weight basis the average percentage composition of the 2 Very ('huffy pigs was 55.1 percent dry matter, 10.0 percent crude protein, 42.1 percent fat, and 1.92 percent ash. The correspend- ing figures for the Intermediate-type hand-fed pigs were 53.9, 11.4, 38.9, and 2.35 respectively ; and for the Rangy pigs, 50.3, 12.3, 35.0, and 2.37. The average gross energy content per gram of empty weight for the three types was 4,350, 4,254, and 3,932 small calories. Composition of Gains up to a Weight of 225 Pounds. Estimates of the average percentage composition of the gain from 55 to 225 pounds for the Very ('huffy pigs and from 70 to 225 pounds for the other two types follow: Crude protein Type matter (Nx6.0) pet. A, Very Chuff y C, Intermediate, hand -fed C, Intermediate, self -fed. D, Rangy Dry matter l>ct. 56.6 57.1 58.6 51.7 8.4 10.6 9.3 11.4 Fat pet. 45.8 43.7 47.7 38.0 Ash pet. 1.61 2.23 1.58 2.19 Gross energy per pound 2.066 2.095 2.234 1.875 562 BULLETIN No. 323 [May, TABLE 67. WEIGHTS OP SAMPLES AND PHYSICAL COMPOSITION OF DRESSED CAR- CASSES OF THE 275-PouND PIGS: SECOND EXPERIMENT Pig No. Offal Carcass composite Lean Fat Skin Bone Total Type A Very Chuffy 5 kgs. 14.97 kgs. 45.26 kgs. 39.16 kgs. 4.54 kgs. 9.40 kgs. 98.36 Average in percent (46.0) (39.8) (4.6) (9.6) (100.0) Type C Intermediate 10. 15.69 44.52 42.06 4.76 9.16 100.50 12 15.62 40.76 41.54 5.56 11.96 99.82 Ifi 14 96 37 26 48.32 3.92 9.26 98.76 17 14.85 38.36 47.40 5.04 11.36 102.16 Average. . . . 15.28 40.22 44.84 4.82 10.44 100.32 Average in percent (40.1) (44.7) (4.8) (10.4) (100.0) Type D Rangy 1. . . 12.03 42.84 38.44 4.86 11.46 97.60 3. 14.55 40 20 44. 16 4.48 10.10 98.94 6 15 61 46 48 36 24 5 22 11.78 99.72 10 14.70 45.50 38.34 5.20 11.28 100.32 13 15.23 43.56 39.78 5.20 11.88 100.42 14 42 43.72 39.40 5.00 11.30 99.42 Average in percent (44.0) (39.6) (5.0) (11.4) (100.0) The smaller fat content of the gains of the Rangy pigs and the greater fat content of the gains of the self-fed Intermediate pigs are worthy of special note. Composition of Pigs Slaughtered at 275 Pounds. Only 1 Very Chuffy pig was killed at a weight of 275 pounds, while 4 Intermediate and 5 Rangy pigs were slaughtered and analyzed at this weight. The data obtained are presented in Tables 66 to 70, in the same form as the data for the other groups of pigs. Little comment on these results is needed, since essentially the same relations hold between the types at this \veight as at the other weights. The average percentage composition of the pigs on the empty- weight basis is given in Table 71. Average Percentage Composition of Gains up to 275 Pounds. For the Intermediate and Rangy types it appears profitable to com- pute the percentage composition of the gains put on from an initial 19S9~\ ENERGY AND PROTEIN REQUIREMENTS OF GROWING SWINE 563 FIG. 5. REPRESENTATIVE CARCASSES OF VERY CHUFFY, INTERMEDIATE, AND RANGY PIGS SLAUGHTERED AT APPROXIMATELY 275 POUNDS LIVE WEIGHT: SECOND EXPERIMENT These carcasses showed essentially the same relations in physical and chemical composition between the types at this weight as at the other weights. weight of 70 pounds to a weight of 275 pounds. Such computations, based upon the composition of the control pigs and of the pigs exam- ined at weights approximating 275 pounds, follow: for the Inter- mediate pigs, dry matter 60.9, protein 9.5, fat 49.9, and ash 2.04 per- cent; for the Rangy pigs, dry matter 58.8, protein 10.7, fat 45.8, and ash 2.27 percent. The gross energy of the gain per pound for the Intermediate type is 2,310, and for the Rangy type 2,187 calories. Comparison of Results Obtained for Pigs of Different Weights. The experiment of the second year affords the opportunity for deter- mining the changes in the composition of the carcasses of growing and fattening pigs with advancing age. Tables 72, 73, and 74 have been constructed to facilitate a comparison of the groups of pigs ex- amined at different weights. In all types increasing weight (and age) was associated with increasing percentages of fat and dry matter and decreasing percentages of protein and ash. This relation is particu- larly well shown in the pigs of the Intermediate type, in which the changes in composition with age proceed in a very regular fashion. 564 BULLETIN No. 323 TABLE 68. PERCENTAGE COMPOSITION OF DRESSED CARCASSES OF THE PIGS KILLED AT APPROXIMATELY 275 POUNDS: SECOND EXPERIMENT Pig No. Dry substance Crude protein (Xx6.0) Fat Ash Gross energy ppr gram Type A Very Chuffy 5 pet. 61.70 pet. 11.22 pet. 47.35 pet. 2.18 sm. cols. 5 155 Type C Intermediate 10 63.48 11.58 49.80 2.71 5 213 12 HI .7.') 10.86 47.93 2.73 4 974 16 67.12 9.18 55.56 2.12 5 697 17 67.32 10.32 .54.24 2.48 5 516 Average 64.92 10.49 '51.88 2.51 5 350 Type D Rangy 1 . 61.59 11.76 46.62 3.11 5 031 3 64.18 10.80 50 70 2.26 5 208 6 59.40 10.74 45.20 2.82 4 875 10 60.76 11.58 46.17 2.50 4 983 13 61.12 12.00 45.46 2.84 4 835 Average 61.41 11.38 46.83 2.71 4 986 TABLE 69. AVERAGE PERCENTAGE COMPOSITION OF OFFAL SAMPLES FOR THE THREE TYPES OF 275-PouND PIGS: SECOND EXPERIMENT Type Dry substance Crude protein (Xx6.0) Fat Ash Gross energy per gram A 1 pet. 29.93 pet. 12 00 pet. 15 40 pet. .82 sm. cals. 2 221 C . 33 25 12 57 18 13 .85 2 397 D 32.94 13.31 17.52 .88 2 354 'The percentages were obtained on one pig only. Since the greatest change with age is the change in fat content, it becomes a question of interest to determine whether the change in fat content accounts entirely for the changes noted in the other con- stituents. This may be determined by computing the percentages of dry matter, protein, and ash on the fat-free, or "protoplasmic" basis. This has been done for the entire empty carcass, with the results show r n in Table 75. Apparently the fat-free substance of these pigs was very similar in composition regardless of age or type. The Very Chuffy pigs were somewhat more watery than the pigs of the other types, with correspondingly smaller contents of protein and ash. The control pigs also were slightly lower in protein than the older pigs. But it may be said that the fat-free material of all pigs closely ap- ENERGY AND PROTEIN REQUIREMENTS OF GROWING SWINE 565 TABLE 70. PERCENTAGE COMPOSITION AND GROSS ENERGY CONTENT OF THE 275- POUND PIGS ON BASIS OF LIVE WEIGHT: SECOND EXPERIMENT Pig No. Dry substance Crude protein (Nx6.0) Fat Ash Gross energy per gram Type A Very Chuffy 5 pet. 52.29 pet. 10.53 pet. 38.99 pet. 1.82 am. cals. 4 326 Type C Intermediate 10 53.66 10.83 40.81 2.23 4 355 12 52.83 10.42 39.71 2 28 4 199 16 ... 57 54 S 1(5 46.48 1 78 4 834 17 57.27 9.90 44.84 2.06 4 646 Average 55.32 10.02 42.96 2.09 4 508 Type D Rangy 1 52.91 11 11 38 87 2 60 4 272 3 55.92 10.56 43.07 1.93 4 507 6 50.97 10.43 37.66 2.34 4 135 10 . 53.19 11.09 39 39 2 11 4 311 13 54.63 11.77 39.43 2.49 4 270 53.52 ' 10.99 39 68 2 29 4 299 Average of all types 54.12 10.56 40.92 2.16 4 385 proximated the following composition: 76.4 percent of water, 3.02 percent of nitrogen (18.9 percent of N x 6.25), and 3.7 percent of ash. These data indicate that the pig reaches a constant protoplasmic com- position ("chemical maturity") at a much younger age than Moulton 1 has found from a composite study of data from a number of sources. A comparison of the composition of gains between the different weight intervals is made in Table 76. It is apparent that with increas- ing age the fat content of the gains increases, while to a correspond- ing extent the protein and ash contents decrease. From the composi- tion of the gains on the fat-free basis it is evident that they approxi- TABLE 71. AVERAGE PERCENTAGE COMPOSITION OF THE 275-PouND PIGS ON BASIS OF EMPTY WEIGHT: SECOND EXPERIMENT Type Dry substance Crude protein (NxG.O) Fat Ash Gross energy per gram A 1 pet. 54.4 pet. 11.0 pet. 40.6 pet. 1.89 sm. cals. 4 501 C . . . 57.5 10.4 44.7 2. 17 4 688 D... 55.7 11.4 41.3 2.38 4 473 'These percentages are for one pig only. 1 Moulton, C. K. Jour. Biol. Chem. 57, 79. 1923. .' ' Jr . '? ' rr : - -: : li. 4- -t- -i _ *. - _ . 3 tf . ::. * - Wfe: /. . r I XT ^ :_*- n A IMA .0 -. -:. . :. ^; arr WUIUBL. I - wt^d r _.= *=- J**M . _ 77- 7n ^... . 3 :*. H ^, .: _ m> _. . ~m JJTT --VTZf^ET I^t5~ ym m -!-.- C -4. . o - - . tm ".r . . - . ta. ^ 568 BULLETIN- Xo. 323 [May, TABLE 75. AVERAGE PERCENTAGE COMPOSITION OF PIGS OF DIFFERENT TYPES AND WEIGHTS ON FAT-FREE EMPTY BASIS: SECOND EXPERIMENT Live weight Approximate age Number of pigs averaged Dry substance Crude protein (Nx6.0) Ash Type A Very Chuffy Ibs. days pet. 55 122 5 22.5 281 6 22.6 225 2 22.5 348 1 23.2 .!_ .... .... .... 22.6 Type C Intermediate 70 115 5 23.4 209 3 25.2 225 252 6 24.5 275 286 4 23.1 Average ... ... 24.0 Type D Rangy 70 108 5 23.2 210 3 24.6 225 254 5 23.5 287 5 24.5 Average. pet. 16.9 18.0 17.3 18.5 17.5 pet. 3.28 3.69 3.32 3.18 3.45 16.7 18.7 18.7 18.8 18.2 3.23 4.30 3.85 3.92 3.77 17.1 18.4 18.9 19.4 18.5 3.47 4.20 3.65 4.05 3.80 Average of all types 23.6 18.1 3.69 A COMPARISON OF 225-POUND PIGS OF BOTH EXPERIMENTS In order to determine how nearly the '225-pound pigs of the first year's experiment were duplicated in the second year's experiment the average percentage compositions of the dressed carcasses, entire carcasses (live-weight basis), and gains in weight have been collected in Table 77. Altho in general the pigs in the first year's work were slightly fatter than those in the second year's work, the agreement thruout was remarkably good. MEASUREMENT OF TYPE Altho the types of the pigs used in the first experiment can be illustrated by photographs and can be described in a general way. it is obviously desirable in defining the material with which an ex- perimental investigation is concerned to measure it in as accurate a manner as possible. So far as experimental feeds and rations are concerned, this is possible by means of chemical analysis, so that a mere description of feeds and rations may well be considered as a poor substitute for a quantitative definition. 1929} ENERGY AND PROTEIN REQUIREMENTS OF GROWING 569 TABLE 76. COMPUTED PERCENTAGE COMPOSITION OF GAIN< IN LIVE WEIGHT 10 DIFFERENT SLAUGHTER WEIGHTS: SECOND EXPERIMENT Gain in weight fr Dry substance Crude protein (Xx6.0) Fat Gross energy per pound ORIGINAL BASIS T>-pe A Very Chuffy UH. pti. pet. pet. 55 to 173 54.3 10.2 42.0 55 to 225 56.6 8.4 45. S Type C Intermediate 70 to 175. 52.6 11.3 70 to-'- 57.1 10.6 70 to 275 60.9 9.5 49.9 Type D Rangy 70 to 175. . 53.9 10.4 40.3 70 to.'. 51.7 11.4 38.0 70 to 275 58.8 10.7 45. S FAT-FREE BA- 8 Type A Very Chuffy 55 to 175.. 21.2 17.6 55 to 225 ! 19.9 15.5 Type C Intermediate 70 to 175 23.9 18.1 70 to 225.. 23.8 18.8 70 to 275 22.0 19.0 Type D Rangy 70 to 175.. -. - 70to-\' 22.1 18.4 70 to 275... 24.0 19.7 Average -- pet. 2.13 1.61 eaU. 2 O5O 2 070 2.86 2.23 2.O4 1 850 2 090 2 310 2.64 2.19 1 940 1 870 2 190 3.67 - 4.59 3.96 4.07 3.53 4.19 3.93 \ quantitative method of measuring experimental animals is in general use. It is true that in most of the experimental work involv- ing farm animals the object is to test the feed rather than the animal, so that an accurate description of the animal is not so essential as that of the feed. But in experiments such as the one under discussion, in which the relative capacities of different types of animals are being studied, it obviously becomes a matter of importance to the signifi- cance of the results obtained to measure the type or conformation of the animals included in the different groups. 570 BULLETIN No. 323 [May, TABLE 77. COMPARISON OF THE 225-PouND PIGS IN THE Two EXPERIMENTS Dry Crude Gross energy Type Experiment substance protein Fat Ash per gram (NxG.O) Dressed carcass A 2 pet. 62.2 pet. 9.9 pet. 49.2 pet. 2.21 sm. cals. 4 960 B 1 62.3 13.1 45.1 2.73 5 060 c 1 64.3 13.3 46.3 2.71 5 110 c 2 60.6 11.6 45.1 2.52 4 830 D 1 62.2 13.6 44.4 2.93 4 970 D 2 55.9 12.3 40.2 2.73 4 420 Live pig A 2 51.6 9.4 39.4 1.80 4 070 B 1 48.4 10.9 34.2 2.05 3 900 c 1 50.5 11.2 35.6 2.06 4 000 c 2 51.4 10.9 37.1 2.24 4 050 D 1 49.2 11.5 34.1 2.24 3 900 D 2 47.4 11.6 33.0 2.24 3 710 Gain A . . 2 56.6 8.4 45.8 1.61 2 070 B 1 53 8 10.9 40.0 1.95 2 297 C 1 56.9 11.1 42.1 1.96 2 319 C 2 57.1 10.6 43.7 2.23 2 090 D 1 56 1 11 4 41.2 2.22 2 252 D 2 51.7 11.4 38.0 2.19 1 870 With this conviction an attempt was made to apply to swine, in a modified form, a measurement of type that has been worked out by Yapp for dairy cattle at the Wisconsin Agricultural Experiment Station. 1 A type index is computed which measures the proportion the animal would fill of a rectangular solid determined by the animal 's major dimensions. The dimensions chosen for dairy cattle were the height at withers (H) and the horizontal distance (L) from pinbone to point of shoulder. The type index is taken as the ratio of the volume of a rectangular solid equal to H 2 x L, to the volume of the animal obtained from its weight and its specific gravity. It was found that a calf one week of age occupies only 12.6 percent of the volume of such a rectangular solid, while at 22 months of age it occupies 21.2 percent. Evidently the change in conformation of the calf in this interval of time is reflected in the change in type index. J Wis. Agr. Exp. Sta. Bui. 352, 25. 1923. 1929} ENERGY AND PROTEIN REQUIREMENTS OF GROWING SWINE 571 TABLE 78. TYPE INDEXES OF THE CONTROL PIGS: SECOND EXPERIMENT Pig No. Live weight Specific gravity Volume of pig Volume of box Type index Type \ -Very Chuffy Ibs. cu. in. 21 57.4 .'.i!i7 1 594 22 57.6 .986 1 618 23 50.7 .1177 1 435 1M 53.4 .985 1 502 25 49.0 .996 1 363 Average 53.6 .988 1502 Type C Intermediate 3 66.5 "77 1 887 21 70.9 .981 2 003 22 71.1 .988 1 994 JH 68.9 .979 1 951 L't 75.6 .979 2 138 Average 70. 6 . 983 1 995 Type D Rangy 21 69.2 .933 2 054 22 73.5 .879 2 317 23 76.7 .932 2 278 24 68.7 .965 1 974 25 74.7 .984 2 104 ^ge... 72.6 .939 2 145 cu. in. 3 536 4 016 3 646 3 548 3 693 pet. 45.1 40.3 39.4 42.3 36.9 40.8 5 154 5 640 5 396 5 499 5 422 5 422 36.6 35.5 37.0 35.5 39.4 6 031 6 716 6 682 6 151 5 786 6 273 34.1 34.5 34.1 32.1 36.4 34.2 In applying this conception of a type index to swine it was thought advisable to relate the volume of the pig to the volume of a solid more closely restricted to the dimensions of the pig than the solid used for dairy cattle. The plan adopted was to refer the volume of the pig to the volume of a rectangular box into which the pig would just fit. The length of the box would be determined by the maximum length of the pig from snout to root of tail. Its height would be determined by the maximum height of the pig and its width by the maximum width of the pig. These measurements of the pigs were taken with a tape and a caliper made for the purpose. The pig was thrown on its side 1 on a level floor and the maximum measurements were taken with the pig in this position. In the first measurements' made the maximum height of the pig was taken as the height at the rear, but in the later measure- ments the maximum height of the back with the legs stretched straight was taken. The maximum length was the distance along the head and back from the end of the snout to the root of the tail. 1 At the time of slaughter the pig was measured immediately after being stuck and before being scalded. BULLETIN- No. 323 TABLE 79. TTPE INDEXES OF THE 175-Porxi> PIGS: SECOXD EXPERIMENT P>S live 1 Specific **:?." gravity V.-'.'i-.e Of ?.* 1 Volume of box Type index initial type index Type A Very Chaffy Utt. CM. m. m. ut. pet pet. 1 167.0 .933 4 855 11 442 42.4 34.8 - 183.8 .971 11 747 44.6 41.3 1C 190.7 .953 5 542 12 992 -- - Sv 7 > 177.9 .954 5 !>> 13 107 39.4 41.9 19 178.9 .963 5 146 11 568 44.5 42.4 n 167.0 .963 4 SO5 1O 724 44.8 43.8 Average. 177.6 .960 5 12* 1! 930 43.1 40.5 Type C Into mediate ua > .972 5 232 14 910 35.1 29 2 :: 9 .<* 4 S*o 12 .>>.$ 3vS 35.5 182. 6 .957 o 2S6 13 057 40.5 35.0 tow J79 .966 .? 13*5. 13 51$ 3S.1 33.2 Type D Rangy 14.. 169.9 .9W 4 903 14 857 33.0 37.5 15.. IS*. 2 .$** 5 429 15 SOO 34.4 135.6 20... '.74.9 .960 5 045 13 941 36.2 31.4 Average 77.7 .960 5 126 14 vy> 34.5 M.a '-An; I specter gravisy, because of aji error in it* deter nuoation. The specific gravity of the pigs was determined after slaughter. After being bled, scalded, and scraped, the carcass of each pig was lowered into a cylindrical tank made with as small a diameter as prac- ticable, and the rise in water level was measured on a glass gauge running the length of the tank on the outside. From a previous calibration of the tank the volume of the carcass could be readily calculated from the rise in the water level. The volume of the live pig was estimated from that of the carcass by adding the volume of the blood, assuming the specific gravity of the blood to be 1.06. X allowance was made for the volume of the hair and scurf. The results obtained on the four groups of slaughtered pigs are summarized in Tables 78. 79. 80. and 81. In addition to the type indexes of the slaughtered pigs indexes were computed for all animals at the start of the experiment from measurements upon each animal and volume estimates based on the live weight of the pig and the average specific gravity of the control pigs for that type as actually determined after slaughter. These estimates of the initial type in- dexes are included in the last column of Tables 79, 80. and 81. I9t9] EXERGY AXD PROTEIN REQUIREMENTS OF GROWING SWIXE 573 TABLE 80. TYPE INDEXES OF THE 225-PocxD PIGS: SECOXD EXPERIMENT Pi N'o. Lire weight ^p^CltlC gravity Volome o: p: Volume of box Type .rxiex E=:;n_i:*ti initial type ii>itx Type A Very Chnffy a*. c*. tV en. in. ftt. pa.. 11 226.1 .946 6 622 15 100 43 9 37. 205 14 412 3S.3 T> pe C Intel media:* 1 218.6 .990 6 119 15 SO2 38.7 34.0 - 22*. 2 .940 6 724 16 44-5 40.9 34.5 . 224.0 .970 6 39S 15 542 41.2 34.4 224.4 .96 : 6 421 17 541 36.6 37.6 239.2 .964 6 >74 17 425 39.4 26.5 223. S .963 6 442 15 &44 4O.4 32.2 _ - .9*1 6 -:->4 16 94O 39.2 33.2 Average. . . .-- .96* 6 -516 16 52O 39.5 33.2 Type D Rangy >'l . 1 9rV4- 32. S - 9 232.4 219.9 >**.4 .93* .9TS .9-S7 16 62-3 17 32-5 39 . 4 37.5 37.0 32.7 33.3 3O.2 11 240.4 .965 i 6 901 18 O48 38.2 31.8 225.3 .96.S 6 447 17 181 37.5 33.1 Average Z21 .967 17 217 3*.0 32.3 'An average specific gravity is assumed. Apparently the type index chosen is larger the chuffier the type of pig. as would be expected from the method of its computation. It is also evident that for the same type the index increases as the animal fattens. This also is to be expected. However, the variations noted are not large in comparison with the index itself or in comparison with riations obtained within any one type at any one weight. These latter variations are difficult to explain except on the basis of errors in the measurements of the pigs, and to anyone acquainted with the difficulties of measuring a live pig the possibility of considerable error, particularly in determining the maximum width and maximum height, will be readily appreciated. Therefore, until a better method of obtaining the required measure- ments on pigs is perfected, or until the selection of other suitable measurements more accurately obtainable is made, the type indexes of individual animals cannot be considered very accurate measure- ments upon which, for example, selections for small differences in ?;:: r-r- Sta .".n: In. . ' " -T* t TV.. c: nc & r-ot - n. A. JBo* * - _ - -i- i 5fl i at. t ^ i - JL_. " ._ ;. ""! ...'\'I'^ : ~3)Uni.jS? ~r!:;n T:;I?T^-^ *^~'* **; :~ 77 ; rn ^> (iv ^'^ "Hi* '. "- -"- ..1 ~ " ,. 7 "!-':"" ~. '"I.." '1 '.'.'.- .1 ^_ ~ " i];;. ; ill" . ,~~ .. ie linam^cLir^ IH HJCT fiiunr: VTJ. ui IHU-JL u: Hi..* J_T 1~T it T K-r-i.-:. I BQ Jt.i;nr- - ! ^- ^3PI ,L;illtl i^l 1UKL -." "V'i)LUL iyjv]H:ii? "HiiT i urum if -JH K^ii-itr:. ' -er* jLiiiiT7 THIS ... " i.-.in .:". --. m:- *m ~ii _ ' ; t j" ir i IT i mil / . ./_-". . "~ ----"* mr~ i 7 . : . - : . : ~: i ~:f : . _L r 11 ~ul : : LT- :i "11 -- !"\i.ll'- . -- - - - " " ' 11. Ill 1 1 -VI L;- 1. - 1" iHV r*3?"UlU- if fili2Kf?T*-L j '^nr ;r "ii" i---- 11 ~iir " ;ii_i n_.n --1...1 - " _j i-i LI- - : ...-I-- L i: n i 11 _ - 11 - . _- T r. . - _ fgimrB ?- _li *"n.l-l~4T" H _ltf ~;i~uH. tlin^-':55-L Jl - 576 BULLETIN No. 323 [May, TABLE 82. COEFFICIENTS OF DIGESTIBILITY OF THE FATTENING RATION: SECOND EXPERIMENT Daily ration Dry substance Crude protein N-free extract Crude fiber Fat Pig No. Corn Mixture 1 Type C Intermediate grams 2 100 3 140 2 000 grams 510 530 500 pet. 82 80 83 pet. 69 68 73 pet. 90 88 89 pet. 35 23 39 pet. 59 51 61 8 11 Type D Rangy 4 2 690 3 065 2 925 455 735 730 86 82 82 82.5 79 71 74 72.4 91 89 90 89.5 48 36 25 34.3 81 53 52 59.5 12 19 Average l Consisting of 8 parts of wheat middlings, 4 parts of tankage, and 1 part of alfalfa meal. TABLE 83. AVERAGE DIGESTION COEFFICIENTS OF THE RATION FOR THE THREE GROUPS OF PIGS STUDIED Group Dry substance Crude protein N-free extract Crude fiber Fat pet. 69.6 pet. 65.0 pet. 86.6 pet. .3 pet. 70.3 Fat maintenance pigs 83.3 77.6 89.6 33.3 71.9 Fat pigs on full feed 82.5 72.4 89.5 34 . 3 59.5 TABLE 84. AVERAGE COMPOSITION OF FECES FOR THE THREE GROUPS OF PIGS: SECOND EXPERIMENT Group Dry substance Crude protein N-free extract Crude fiber Fat Ash energy per gram pet. pet. pet. pet. pet. pet. am. cals. Young maintenance pigs 49.6 8.56 16.08 6.35 1.77 16.71 1 797 34.8 7.24 16.16 4.30 1.47 5.9$ 1 527 Fat pigs on full feed 30.4 6.56 13.91 3.95 2.51 3.49 1 399 therms for the fat pigs on a maintenance ration, and 3.29 therms for the young pigs on a maintenance ration. Per pound of digestible organic matter, the metabolizable energy for the three groups of pigs was 1.86, 1.89, and 1.94 therms respectively. The metabolizable energy of the ration expressed as a percentage of the gross energy was 78.0, 79.4, and 73.2 for these three groups of pigs in the order given. The nitrogen balance sheets of the six fat pigs on full feed during the ten-day collection periods will be found in Table 86. ENERGY AMI I'KOTKIX RKQI-IKKMIATS <>K (JiiowiNG S\VIM: 577 I ^. 00 "i" CO to .-> t- o GJ ft t^ 'O 00 d t^ 06 oo U 00 r* fc* t* oo r- t- t- " a. o w _ w o - 8.2 S .^ c F oo co oc ^; ^M t i T 00 00 00 00 c H Pk ^* & '. V S i S j * 1 S S "3 a J - 3 5 S _M| J^r co co co co 5 ^ b S T3 1 ) J 2 3 =3 H fe C O CO 00 I^OON 00 00 M Tfl * 00 H a ^ ^H ^- j i 3 c 4) M H r 4 > H I a > S o 'C V a 55 iO *# & E rf o oo h CO c >c o LI -1< * o 5 H K 3 1 S i o 4 I c g H 4 3 i 5 g a c 13 1 1 O 00 s * 1-1 M ^ tf i 0) a >> CO I-H -t< t>. o *o --i IN IN es per gra ^ a H 'C 4 _o S s > j B >T3 2 r = H 1^15 O CO O to IN tO "3 o 10 -* 3 g 2 S r~ a j 1 ^ I ^ O5 ~H Ci co co *o a _o d ^ a c! 3 3 (N (N ^ -f m o *" 4 jj ^ O 00 Ol IN m oo -^ Q < * 1 . S co * co 1C *O *O g ^ 9 > o -a O CJ 'I 3 o to co oi 00 "5 to 00 O -J> "o O S 5 1 U 3 1 3 O r~ -H 3 ! * $i Si JS M i' H CM C^ IM CO CO O IN fr) IN uilibrium I o 1 Q) O o fi i tie 1 K 1 <; 9 to' oo -' -1< 01 C3 578 BULLETIN No. 323 [May, TABLE 86. NITROGEN BALANCES OF THE FAT PIGS ON FULL FEED : SECOND EXPERIMENT Pig No. Nitrogen of feed consumed Nitrogen of feces Nitrogen of urine Nitrogen balance Type C Intermediate 6 grams 46.24 grams 14.08 grams 21.85 grams 10.31 8 60 48 19.36 27.93 13.19 11 45.92 12.16 14.56 19.20 Type D Rangy 4 58.88 12.64 29.04 17.20 12 66 56 19.68 33.35 13.53 19 75.52 19.52 37.62 18.38 RELATION OF FEED CONSUMED ABOVE MAINTENANCE TO GROSS ENERGY OF GAINS For the 13 pigs slaughtered at weights approximating 225 pounds the relation between the amount of feed consumed above the esti- mated maintenance requirements and the estimated gross energy con- tent of the gains has been computed, with the same reservations con- cerning its significance that have already been explained in connection with similar computations of the preceding experiment. The results will be found in Table 87. The maintenance requirements have been taken from the results of the maintenance trials of the experiment of the first year, for reasons explained elsewhere (page 544). The re- quirement for Chuffy pigs of that experiment has been applied to the Very Chuffy pigs of this experiment. As an average for the 13 pigs it appears that each 100 pounds of ration consumed above the estimated maintenance requirement pro- duced a storage of 74.8 therms of gross energy in the carcasses of the growing and fattening pigs. This is lower than the average value for the 45 pigs of the preceding experiment, 89.5 therms, and is much lower than would be expected from Armsby's estimates of the net energy value of the ration for swine. The average metabolizable energy content of the ration, as deter- mined from the three groups of pigs upon which digestion trials were run, involving 23 individual pigs, is 3.35 therms per kilogram of dry matter. The average dry matter content of the ration is 85.32 per- cent, so that metabolizable energy per kilogram of ration is 2.86 therms, or 129.9 therms per 100 pounds. If 100 pounds of the ration possessed a net energy value of 74.8 therms for these fattening pigs, the percentage availability of the metabolizable energy would be 57.6. This is considerably less than the percentage estimated by Armsby, 78.14, but approximates the expected performance of the steer. 1929] ENERGY AND PROTEIN REQUIREMENTS OF GROWING SWINE 579 - pq - o z. -" 3> * ~J" ^ ^ ^ M r- - re 71 bt ^ M aS IQ re i- 1 71 l~ -~ X re -^ 71 f^ f sC re 71 a f. ^ O n t~ H i-e IN -S_ cf 1-4 1-4 9 o IN ~ - * co C ^ re t~ 71 t; J-. 00 i4 r4 ea CO i-e ie oo 71 (N ~ ~ -. - N ? re r. ei M re M r- i-e re 00 71 71 r- t -r re 71 7, f 5 o cc re re t^- i-e ""i^ c OS * 1 8 re 71 '^ --ex gg ' re t ei vr ie re ^ ^ a - C N '-r re i IQ - 71 -^ a - -: - Q r-4 r4 CO i-H (N -*> Mi 71 r- i-e re ^ r. r~ o to c^ C: -< 00 - -i f ~ ej -^ i-e re c; ~ "" ^ S t^ S. 00 00 - us oo oo 1 N ^ -H f-H !> CO co pg 5 I >> II ^ '~ t^ O) if} ?? f-4 ^H CO $ o fe o o 7) -5 re t 71 -H 1-H S t- CO - ^ re ( . ! - ^ = ^ .= A 5 . "= = a ^ : ? 1 " J: - . = = : = - -: 'P = "H I-'inal u< Initial v. - (iain Average urn- lit Days on exparim Maintenance fed I'rl ! I'er lieail Total feed '1 "lal tri-il for in Total feeil CIIIIMI 100 pounds fc maintenance. . 580 BULLETIN No. 323 [May, Admittedly the calculations discussed in this section are indirect and are based upon questionable assumptions. The average direct experimental data for the group of 13 pigs are as follows : in a feeding period of 147 days a pig averaging 137 pounds in weight consumed 678 pounds of the experimental ration containing 807 therms of metabolizable energy. This amount of metabolizable energy sufficed to cover the pig's maintenance requirements and to produce a gain in body tissue containing 315 therms of gross energy. The conclusion that the energy gained represented only 57.6 percent of the metabo- lizable energy used for that purpose depends upon the validity of the assumption that the metabolizable energy required per unit of weight for maintenance is the same in the period of full feed as in the period of maintenance feeding. In the present state of knowledge of energy metabolism it seems profitless to discuss the probable accuracy of this assumption and of the conclusion based upon it. However, other evidence may be cited to the effect that the percentage utilization of feed energy by swine is greatly exaggerated in Armsby's estimate of the net energy value of feed for this species. In Research Bulletin 73 of the Missouri Agricultural Experiment Station Hogan, Weaver, Edinger, and Trowbridge report the results of an experiment designed to determine the relation of feed consumed to energy retention in swine. Sixteen pigs were slaughtered at weights ranging from 100 to 300 pounds, and the carcasses were submitted to complete chemical analysis. By comparing the energy content of pigs of different weights, estimates were made of the corresponding gains in energy, and from the amounts of feed consumed in the time required for these gains, the net energy consumed was estimated by employing Armsby's values. 1 Upon deducting from the estimated net energy intakes the estimated gross energy contents of the gains, estimates were secured of the net energy required for maintenance. These esti- mates, expressed per square meter of body surface per day, averaged approximately 3.000 calories. Now the basal metabolism of the pig may be taken roughly as 1,000 calories per square meter per day. 2 It seems extremely improbable that the requirement of energy of the active pig for maintenance should be three times its basal heat pro- duction. For example, a pig weighing 100 pounds (surface area 1.097 square meters, according to Hogan et al) standing 12 hours out of the 24. with an assumed increased energy expenditure of 20 percent, would have to travel 36 miles a day at a lively canter for a pig in 1 Armsby, H. P. The nutrition of farm animals, 722. 2 Deighton, T. Boy. Soc. (London) Ser. B. Proc. 95, 340. 1923. Rapport, D., Weiss, R., and Csonka, F. A. Jour. Biol. Chem. 60, 583. 1924. Wierzuchowski, M., and Ling, S. M. Jour. Biol. Chem. 64, 697. 1925. Wood, T. B. Jour. Agr. Sci. 16, 425. 1926. Armsby, H. P. The nutrition of farm animals, 285. 1929] ENERGY AND PROTEIN REQUIREMENTS OF GROWING SWINE 581 order to expend the equivalent of 3,000 calories per square meter of body surface daily. 1 It may be doubted whether a fattening pig would exhibit this much activity or anything approximating it. Hence the estimate that the maintenance requirement of these pigs averaged 3,000 calories daily per square meter of surface may be con- sidered much too high. In inquiring concerning the source of error it appears reasonable to suppose that it is directly traceable to an excessive estimate of the net energy intake of the pigs based upon Armsby's net energy values and, therefore, that these estimates are themselves much too high. This is the conclusion to which the data of these type experiments also point rather definitely. In examining critically the experimental evidence upon which Armsby based his estimates of the heating effect of food on swine (loc. cit., 653-656), the necessity of assuming thruout an average value for the fasting catabolism with which to compare the heat production on feed must detract considerably from the accuracy of the estimates made. Furthermore, this method is not analogous to the method used for cattle, in which the heat production of periods on different levels of feed is compared, since it involves the heating effect of the food consumed rather than the heating effect of increments of food im- posed upon a basal amount. When the method applied to swine by Armsby is applied to steers, much smaller heat increments per unit of feed than those reported by Armsby- are obtained. 2 The heat increments thus computed for swine are not particularly concordant among themselves, and the differences obtained between different feeds are frequently so unexpected as to constitute circum- stantial evidence of the unreliability of the method of computation or of the data to which it has been applied. The extremely high heating effect of palm oil and the greater heating effect of straw pulp than of wheat gluten may be cited in this connection. The fact that no experimental data are available on the heating effect of most of the feeds whose net energy values have been estimated may also be men- tioned. For these reasons it must be concluded that no satisfactory estimates of the net energy value of feeds for swine are at present available. NUTRIENT REQUIREMENTS OF PIGS The most satisfactory estimate of the nutrient requirements of growing and fattening pigs, in terms of the expenditure and storage of nutrients in the body of the pig rather than in terms of digestible 1 Assuming a very liberal expenditure in horizontal locomotion of .8 small calories per kilogram of weight per meter traveled. 2 Forbes, E. B., Fries, A. J., Braman. W. W.. and Kriss, Max. Jour. Agr. Res. 33, 489, Table 4. 1926. BULLETIN No. 323 food nutrients, 1 should be based upon established relations between (1) age and body weight, (2) body weight and chemical composition. and (3) age (or weight) and the minimum expenditures of nutrients compatible with the maintenance of life. The data secured in the swine-type studies described in the preceding pages afford informa- tion with respect to relations 1 and 2. Other published investigations also throw light upon these points and also, to some extent, upon rela- tion. 3. It appears possible, therefore, by the use of all available information to reach some definite, tho evidently only tentative, con- clusions concerning the nutrient requirements of fattening pigs. RELATION OF WEIGHT TO AGE For growth alone it should be possible to establish a significant relationship for each species or breed of animals between age and weight were it not for the fact that for many of the different "improved" breeds of farm animals growth is usually accompanied by what must be considered physiologically as an excessive deposition of fat. A certain rate of fat deposition is undoubtedly associated with normal growth. Hence with animals such as swine, that readily fatten during growth, it is difficult to decide just how great a rate of fat deposition is essential for normal growth : and since excess fat may be deposited at greatly varying rates, observed relationships between age and weight in the case of swine are lacking in definite significance, normal growth curve'"' for swine can be justified as such without a demonstration that K - fat deposition did not occur in animals from which the data were secured, while no age-weight curve for growing and fattening swine can possess a definite meaning unless it represents the maximum performance. For these reasons nothing definite is known concerning the normal growth rate for swine and no normal rate of fattening can be said to exist. The time relations of these processes have thus defied stand- ardization. A comparison of the age-weight relation of the individu- ally fed pigs of the swine-type studies with that published by the uri Agricultural Experiment Station is of importance to the later discussion. Such a comparison will be found in Table 88. In the experiment of the second year the withdrawal of pigs for slaughter was started when the pigs were about 28 weeks of age. Since the animals thus removed were generally among the heaviest of their respective groups, an attempt has been made, by removing from consideration also correspondingly lighter pigs, to obtain average weights fairly representative of the ages given. Considerable differences in the rate of weight increase occurred 1 Mitchell. H. H. The determination of the protein requirement of animals and of the protein values of farm feeds and rations. Bui. Xatl. Research Council. 11, Part I. Xo. 55. 1926. ENERGY AXD PROTEIX BEQCIREMEXTS OP GROWTXG SWIXE : '- - ' ; _ a z - - : 1 * - I , - - - ] 1 - - -' - 7 - ... "Z - a * t^ r r - r - - I jj _ I _ - X o -a c E 1 I Z _: - 1 . r ; t H *** :2 :2 :2 != :2 : : :2 .2 ! = = : : : : i | - - - - : r - r - - : - - r - - - - - ___- -" 1 I H 2 2 S ^ : r 3 r - r _ = E r fjs - - - r c - 5 _ r ~ o S = - i J E - - j - - r . _ 5 M - || " c r- ~ - - - \ =3 -; :- - - _ - = .= - - .- - - - < >|...IH III ...l\ = 5 _ - - _ - -- _ r. -. r. -.-.-.-. r. -. r. r: -: -:.-:-:: 586 BULLETIN No. 323 [May, a o u I fe o S ...... ...o.-o-o OJ 1 ^T<- e* et ei et 04 3 4- , o co in CM ^* -in M "H &"::::: 23::3:S *c 1 ! . W C5 Ci * -00 *^t* -^ M 10 "C s Ill 1 ^ : : : M IN : : ; ' ^ - 7 g o rt I - >> s co CM ic * ic ~ ^ g c s o i g_ C5 O t~ Ci CM OC W > 1 a *:|> N :>J: > Trowbridi 18, 51. I - . -^^i^o -co -* - 4 1 c^-CCCOCOCO -CM 'CM * H ft ^ ^ CO O lO * *O '00 < fe fe ^ r~ w m * -CM -cj> u C -H T-I rt IN CO CO M _ o T3 '3 ^ - 3 -2 to olg S. : 2 2 S 2 : 2 : : 2 : : : : . i, Jl CO x 1 - .- o o -m - - - fcT *c 4) s 5 ! S -r c M >: R -cococo-* * ->n ll "S 00 . M 'r-t-t^t^ 'c- ' ' c- ' ' ' ' r c Oo e | a la 5 | |2 p 1 : : :S : : :g : : :g : "3 IN -CO -CO -V i/5 _fl . . n f <- -CM- 2 ^ M CM IN -2 1 ^ g G o3 K : : : S : : : 5 : :S :3 : d j! a O "X . . -o -IN -CO--O co ->-i -m i-i o | -c i^I c S PH ^ C w F! - o *53 i$\il\\\\\\\\\\ a if '- p 3 ^ a w 8 ax rt 2 S? S S S S 2 | g 8 "11 1929} ENERGY AND PROTEIX REQUIREMENTS OF GROWING SWINE 587 : O o U N ^c=--oc----i- g. * re re" : | CC ^ -re' o = S . t~- re -M -,: oo >-: A ~ E r* ^fj - IX >. Z . r- - j: to -re r: - z _ ~- ei M ~i w c5 it *}< - M M - - M ?1 - M .. - rc . ~ -- ^, .... < - z ^ -5 -r -'. n " ~ c s. ^i a a & : :2 :S :g : :^ : : : : - CO CO CO t~ CO ' - I I f) ~1 i~ - i~ * W W M "1 M ' M ' ' ' ' ^ s >^ > > jo , ; ; ... wow ... ..e 5 E : - II ... .^ - .^ ...-..,- I - o Ig s i- ^ r- ~ o . '5 ;= >, I . 10 a . tt I' 5 IT; i~ o M CO o s oi 11 ^ ::::::::::::: 2 ' 5 a * ^r = - . ^^_l .NNNC^c^re - 2 - - - ! I J "=<_ o ~ -5. ~f '>. , - = .1 -a I - = '-- ^T- r: ^ r r; -^ - ^_ > E III cil E = > : 588 BULLETIN- Xo. 323 [May, TABLE 91. COMPOSITION OF PIGS OF DIFFERENT WEIGHTS ox EMPTY FAT-FREE BASIS, FROM DATA OF WOOD Animal Xo. Age Live weight Fat content Composition of fat-free empty animal Dry matter 1 Crude protein Ash 7. . . days 26 24 26 100 141 186 206 78 119 164 Ibs. 14.8 14.1 16.0 28.0 61.0 105 164 208 34.5 97.0 140 pet. 15.7 18.5 14.5 12.7 8.7 14.2 15.5 26.6 10.5 14.9 16.0 pet. 23.3 19.4 19.0 21.0 21.6 23.4 25.1 29.1 22.9 21.9 22.6 pet. 19.0 16.4 15.6 17.3 18.0 19.4 21.2 25.1 17.4 17.8 18.2 pet. 4.3 3.0 3.4 3.7 3.6 4.0 3.9 4.1 5.4 4.1 4.5 20. . 29 3 4. . . . 8 31 9. . 2. 32 determined indirectly by summation. TABLE 92. COMPARISON- OF COMPOSITION OF Sows AND BARROWS AT A WEIGHT OF APPROXIMATELY 225 POUNDS, ox LIVE- WEIGHT BASIS Percentage composition Type Xo. of pigs averaged Gross energy per gram Dry matter Crude protein i.O) Fat Ash sm. cols. B 4 49.13 11.14 34.96 2.07 3 935 Barn 11 48.18 10.85 33.99 2.04 3 891 6 11.12 34.66 2.02 3 935 BatT' 9 51.11 11.33 36.22 2.09 4 037 D 47.37 11.95 32.16 2.36 3 727 Barrows. . . . 13 49.46 11.47 34.45 2.22 3 929 The recomputation of Wood's results on the empty fat-free basis brings them into essential agreement with the American data, as is evident from Table 91. Thus the difference in the composition of pigs of different weights depends upon two factors. The most important factor is the fat content, which seems to be dependent primarily upon the system of feeding, particularly upon the amount of carbonaceous feed consumed above the requirements. The second factor is the varying composition of the protoplasmic tissues, which is unrelated to the method of feed- ing and probably dependent either upon the chronological age of the 1929] ENERGY AND PROTEIN REQUIREMENTS OF GROWING SWINE 589 animal or upon its physiological age as represented by the growth attained. Under the conditions of feeding represented in the Ameri- can investigations reviewed, the protoplasmic composition of develop- ing swine appears to reach approximate constancy ("chemical ma- turity") when a weight of 150 to 175 pounds is reached, so that pigs of greater weight will differ in composition in accordance with their fat content only. The swine-type experiment of the second year affords the oppor- tunity to determine whether the composition of sows differs materially from that of barrows. Among the 225-pound pigs examined in this experiment enough sows were included to make a comparison possible. The average results of sow and barrow analyses in the different types are summarized in Table 92. Evidently no considerable sex difference existed. In this respect swine differ from poultry, i.e., pullets fatten more rapidly and grow more slowly than capons, 1 and also from cattle, i.e., heifers fatten more rapidly than steers. 2 RELATION BETWEEN AGE AND MAINTENANCE REQUIREMENTS The maintenance requirements of swine for any nutrient may be factored into the amount required to supply the basal (or minimal) expenditure and the amount required to supply the expenditure in the muscular activity more or less characteristic of the animal under usual farm conditions. Considering energy requirements first, the basal energy expendi- ture of swine has been determined by Tangl, 3 who obtained an aver- age value of 1,100 calories per day per square meter of body surface for two young growing animals about 7 months of age and weighing 40 to 50 kilograms, and an average value of 1,060 calories on the same basis for two animals about 15 months old and weighing 110 to 120 kilograms. These figures represent the heat production of pigs lying down, from 72 to 96 hours after the last meal. E. Voit 4 has recalcu- lated the results of some earlier and less carefully controlled experi- ments of Meissl 5 on two adult fat hogs and has obtained values of 1,064 and 1,086 calories per square meter of surface per day. Recently Deighton (loc. cit.) has studied the basal heat production of a pig at different ages and has found it to vary greatly and in much the same fashion as that of man. At birth and shortly after, it is low ; it rises to a maximum, 70 percent above the adult level, at 4 months of age ; and then decreases until 12 months of age, at which time only Mitchell, H. H., Card, L. E., and Hamilton, T. S. 111. Agr. Exp. Sta. Bui. 278. 1926. 2 111. Agr. Exp. Sta. Ann. Rpt. 1927-28, 99. Tangl, F. Biochem. Ztschr. 44, 252. 1912. 4 Voit, E. Ztschr. Biol. 41, 113. 1901. 8 Meissl, E. Ztschr. Biol. 22, 63. 1886. 590- BULLETIN No. 323 [May, TABLE 93. METABOLIZABLE ENERGY REQUIRED FOR MAINTENANCE OF SWINE OP DIFFERENT AGES COMPARED WITH THEIR BASAL METABOLISM Weight Assumed age Surface area 1 Metabolizable energy required for maintenance Basal metabolism per day According to Deighton 2 Assumed at 1,000 cals. per sq. m Ibs. 30 mos. 2 3 5 6.5 8 9.5 sq. m. .433 .609 .966 1.266 1 . 534 1.780 cals. 620 1 000 1 860 2 570 3 140 3 570 571 993 1 623 1 914 1 988 2 051 cals. 433 609 966 1 266 1 534 1 780 50 ... 100 150 200 250. . . 'Computed by the Meeh formula, using Hogan and Skouby's constant of 777 (Jour. Agr Res 25, 419, 1923.) 2 Taken from Deighton's curve (loc cit ) is the constant adult value of approximately 1,000 calories per square meter of surface attained. Later observations by Deighton. cited by Wood (loc. cit.), indicate considerable variability among different pigs, but the existence of a high level of basal metabolism at 4 months of age is confirmed. The results of the two swine-type experiments reported herein permit a statement of the maintenance requirements of pigs of dif- ferent age in terms of metabolizable energy on the assumption that the requirement per unit of weight from the 50-pound to the __!'>- pound pig varies in a linear fashion. A comparison of these values for pigs at different age and weight with estimates of the basal heat production is given in Table 93. The amount of metabolizable energy required for maintenance is evidently a maximum figure for the net energy requirement that would be attained only if and when the metabolizable energy is 100 percent net available. It should be higher than the basal heat pro- duction for another reason, since it probably includes a considerable expenditure of energy for muscular activity, particularly horizontal locomotion. Hence the close agreement of the values in columns 4 and 5 of Table 93 for the 30- and 50-pound pigs is difficult to explain except on the basis of errors either in the estimation of the metabo- lizable energy requirement or in the basal metabolism. Since the former is based upon 15 determinations (Table 18), even tho indirect, while the latter is based upon direct observations on one pig only, it may perhaps be justifiable to accord the greater significance to the metabolizable energy value and to conclude that the basal metabolism of the young pig is not so intense per square meter of surface as Deighton's limited data would indicate. The adult level of basal metabolism is computed in the last column of the table. K \KKGY AND PROTEIN REQUIREMENTS OF GROWING SVTINK 591 TABLE 94. DAILY EXCRETION OF I'm \.\HY XITROGEN HV SWI.VE SUBSISTING ON Low-XiTK 1.60 .072 25 1 32 .053 PfeifTer 3 26 3 1.19 .045 Pfeiffer 37.2 1.61 .043 MeColluni and Steenbock 38.1 2.00 .052 Mitclioll and Kick* 38 1 1.88 .049 Mitchell :uile differences between types in spite of large differences in their market finish. The dressed carcasses of pigs of distinctly different type slaughtered at the same weight, altho differing distinctly in market finish, analyzed very nearly the same. Apparently these carcasses differed in the distribution of fat but not in the content of fat. These results are in agreement with those of Hogan, Weaver, Edinger, and Trowbridge, obtained at the Missouri Agricultural Ex- periment Station (Research Bulletin 73). More or less distinct type differences were noted with reference to the amounts of feed required to maintain energy equilibrium. In general, especially at the heavier weight, the Intermediate-type pigs were more economical of food energy in maintenance, particularly in comparison with the Chuffy and Very Chuffy pigs. This may have been due to less muscular activity or to a less persistent growth im- pulse under adverse conditions of feeding. With reference to the utilization of feed no type differences were detected. Mitinti nance Requirements for Body-Weight Equilibrium, Of a ration consisting of yellow corn, middlings, and tankage, approxi- mately 1 pound per day per 100 pounds live weight (weight ratio) was required for the maintenance of body weight, both in the case of the young pigs weighing 50 to 70 pounds and also in the case of the fat pigs weighing 225 pounds and more. Changes in Composition of Pigs on Maintenance Ration. A com- parison of the composition of the maintenance pigs at the end of their period of feeding with their probable composition at the beginning indicated clearly that profound changes had occurred, particularly in the young pigs. These changes consisted of a more or less extensive withdrawal of fat and corresponding storage of water, protein, and ash. The period of inadequate feeding on a well-balanced ration had effectively suppressed body-weight changes but had not suppressed growth. Among the young maintenance pigs of the first experiment, as a result of these changes in composition during a feeding period of 110 days, the energy content of the body decreased on the average 31 per- cent for the Chuffy pigs, 28 percent for the Intermediate pigs, and 16 percent for the Rangy pigs. Among the 225-pound maintenance pigs the average losses of body energy were 21, .5, and 15 percent respectively. In the second year's work the young maintenance pigs were not slaughtered, and the fat maintenance pigs, heavier and older than the corresponding pigs of the preceding year, showed only inconsiderable changes in energy content. 598 BULLETIN- Xo. 323 [May, Maintenance Requirements for Energy Equilibrium. On the basis of changes in composition of the pigs during the period of maintenance feeding, and also the basis of total amounts of feed consumed, it is possible to estimate the amounts of feed required to maintain energy- equilibrium; in other words, to prevent a loss of energy from the body rather than merely a loss in weight. This estimate involves the use of certain simplifying assumptions, the accuracy of which is fully discussed in the text. For the maintenance of energy equilibrium it seems necessary to provide about 1.50 pounds of the ration used per 100 pounds live weight (using the weight ratio) for young pigs weigh- ing 50 to 70 pounds. For older pigs, weighing 225 pounds or more, the first experiment indicated an average requirement of 1.13 pounds of feed, and the second, .95 pound, values not greatly different from those previously given for the maintenance of body weight. Certain average type differences were obtained, but their significance is diffi- cult to assess because of the small number of pigs in each maintenance type group, and the variation among the individual estimates secured. Digestibility and .~\[< 1uboli:abl< Energy of Experimental Ration. The digestibility and metabolizable energy value of the rations used in the two years' work were not appreciably affected by the level of feeding (maintenance as compared with full feed) or by considerable changes in the proportions of the individual feeds. Per kilogram of dry matter, the metabolizable energy averaged 3.347 therms for the fat pigs on full feed. 3.440 therms for the fat pigs on maintenance feed, and 3.287 therms for the young maintenance pigs. Expressed as a percentage of the gross energy of the ration, the metabolizable energy averaged 78.0. 79.4, and 73.2 for these three groups of pigs in the order given. CJiangi* in Composition of Pig* With Age. The percentage com- position of the pigs killed at increasing weights exhibited the expected changes, that is. increasing contents of dry matter and fat and de- creasing contents of protein and ash. The results were quite com- parable with those obtained in recently reported experiments from the Missouri Agricultural Experiment Station and from the U. S. De- partment of Agriculture Experimental Farm at Beltsville. Maryland. On the basis of the fat-free empty weight, the so-called "proto- plasmic"' basis, much of this variation in composition disappears, in- dicating that it is largely due to varying percentages of fat. In fact, after a weight of 150 to 175 pounds is reached under ordinary condi- tions of feeding, corresponding to an age of 25 to 30 weeks, the com- position of pigs 011 the protoplasmic basis appears to be remarkably constant and to be unaffected by the system of feeding. This proto- plasmic composition characteristic of maturity consists of 75 to 76 percent of water. 20 to 21 percent of crude protein, and approximately 4 percent of ash. 1929] ENERGY AND PROTEIN REQUIREMENTS OF <;K<>\VIN<; SWINE 599 Effect of >V.;- inl h'aft of (inlii on Composition of 8 The composition of sou carcasses at a weight of 225 pounds is imt appiv- ciably different from that of barrow carcasses, the system of feeding being the same. Swine are thus clearly distinguished in this respect from cattle and poultry in which the female at any given weight (except for extreme immaturity) is distinctly fatter than the castrated male. The composition of swine carcasses at t! >und weight and of the gains put on to that weight are not affected, or are affected only to an inconsiderable extent, by variations in the rate of gain ranginir from .7-') t> 1.25 pounds per day. t: :u of feeding re- maining the same. /> ^ribution of A<1<1<<1 Xui runts in Carcass. In gaining weight from 65 to 225 pounds the pigs in this experiment deposited 74 per- cent of the added dry matter. 58 percent of the added protein. 15 per- cent of the added ash. and 78 percent of the added energy in the boneless meat of the dre Jity percent of the added ash was stored in the skeleton. Approximately 50 percent of the added protein and 24 percent of the added energy were stored in lean meat. \i / En< ran Value of Ration*. On the basis of certain simplifying assumptions it has been computed that the net energy value of the rations for growth and fattening averaged 89.5 therms per 100 pounds in the first experiment and 74.8 therms per 100 pounds in the second experiment. These values are much lower than would be expected from Armsby's computations of the net energy values of feeds for swine. Other evidence is cited and discussed in the text in support of the conclusion that swim are considerably less efficient in the utilization of feed energy than Armsby has estimated. '/ "t of Type. An attempt to measure the conformation, or type, of the pigs was made in the second year's experiment, based upon the reference of the volume of the pig to the volume of a box the three dimensions of which are determined by the maximum length, height, and width of the pig. The type index chosen was the percent- age of the volume of this box that would be occupied by the pig. The index is larger the chuffier the type of pig; and for pigs of a given type it is larger the fatter the pig. From a study of the numerous type indexes obtained in this ex- periment it appears that the one chosen is subject to wide individual differences, due probably to the difficulty in securing accurate dimen- sional measurements of pigs and to the fact that the differences be- tween the types of pigs used in this experiment are not large. How- ever. it is believed that the average index for a large group of animals of similar type and weight must be conceded a greater value as a quan- titative description of type, or conformation, than a worded descrip- tion. or a group photograph or a group of individual photographs. 598 BULLETIN- Xo. 323 [May, Maintenance Requirements for Energy Equilibrium. On the basis of changes in composition of the pigs during the period of maintenance feeding, and also the basis of total amounts of feed consumed, it is possible to estimate the amounts of feed required to maintain energy equilibrium; in other words, to prevent a loss of energy from the body rather than merely a loss in weight. This estimate involves the use of certain simplifying assumptions, the accuracy of which is fully discussed in the text. For the maintenance of energy equilibrium it seems necessary to provide about 1.50 pounds of the ration used per 100 pounds live weight (using the weight ratio) for young pigs weigh- ing 50 to 70 pounds. For older pigs, weighing 225 pounds or more, the first experiment indicated an average requirement of 1.13 pounds of feed, and the second, .95 pound, values not greatly different from those previously given for the maintenance of body w r eight. Certain average type differences were obtained, but their significance is diffi- cult to assess because of the small number of pigs in each maintenance type group, and the variation among the individual estimates secured. Digestibility and M< i<>li: percent of the added energy in the boneless meat of the dressed carcass. Kighty percent of the added ash was stored in the skeleton. Approximately 50 percent of the added protein and 24 percent of the added tneruy were stored in lean meat. -Vi ' l!