UNIVERSITY OF ILLINOIS Agricultural Experiment Station BULLETIN No. 314 A TECHNICAL STUDY OF THE MAINTENANCE AND FATTENING OF LAMBS AND THEIR UTILIZATION OF A RATION OF ALFALFA HAY AND CORN BY H. H. MITCHELL, W. G. KAMMLADE, AND T. S. HAMILTON URBAXA, ILLINOIS, AUGUST, 1928 CONTENTS PACE PLAN OF THE EXPERIMENT 31 CHEMICAL COMPOSITION OF CHECK LAMBS 33 MAINTENANCE EXPERIMENT 37 Body Weight Changes 38 Results of Digestion and Metabolism Trials 38 Average Daily Intake of Feed and Energy 40 Composition of the Maintenance Lambs 40 Changes in Energy Content of the Maintenance Lambs 44 Corrected Maintenance Requirements 45 Net Energy Required for Maintenance 47 THE FATTENING EXPERIMENT 48 Results of the Digestion and Metabolism Trials 50 Composition of the Fat Lambs 51 Composition of the Gains in Weight 54 Distribution of Added Nutrients in the Carcasses 56 Utilization of Feed Energy in Fattening 57 SUMMARY 59 A TECHNICAL STUDY OF THE MAINTENANCE AND FATTENING OF LAMBS AND THEIR UTILIZATION OF A RATION OF ALFALFA HAY AND CORN H. H. MITCHELL, W. G. KAMMLADE, AND T. S. HAMILTON 1 The lack of information concerning the nutrient requirements of sheep and their efficiency in utilizing food nutrients, is mainly responsi- ble for the general application to sheep of results obtained with cattle, and for the complacency felt in thus transferring bodily to one species information and measurements secured with another. It is high time that experimental investigations on the nutrition of sheep be carried out that will either establish this assumed similarity between sheep and cattle or will permit a separate evaluation of sheep. In Bulletin 283 of this Station is a description of an experiment on 12 sheep designed to determine the maintenance requirement in terms of metabolizable energy, the composition of gains put on during fattening, and the relation between the metabolizable energy consumed above maintenance and the gross energy of the gains made. The ra- tions used in all cases consisted of alfalfa hay only. The rate of fat- tening secured on alfalfa hay alone was slow, and the refusal of feed in some of the metabolism trials as well as during the fattening period complicated the interpretation of some of the results secured. It was therefore decided to repeat the experiment using a ration more accept- able to sheep and more conducive to fattening. In other respects also the plan of the second experiment differed from that of the first tho the objects sought were essentially the same. PLAN OF THE EXPERIMENT The general plan of the experiment provided for the slaughter and analysis of a group of check lambs at the beginning of the experiment and of a group of fattened lambs at the end of the experiment. From these results the composition of the gains put on during fattening could be computed. A third group of lambs was to be fed such amounts of the fattening ration as may be required for the maintenance of weight, The slaughter and analysis of these lambs at the end of their mainten- ance feeding either would demonstrate that the ration consumed was in fact a maintenance ration (with respect to energy) or would afford 'H. H. Mitchell, Chief in Animal Nutrition; W. G. Kammlade, Assistant Chief in Sheep Husbandry ; and T. S. Hamilton, Associate in Animal Nutrition. 31 32 BULLETIN No. 314 [August, a more or less satisfactory' basis for correcting the ration fed by mak- ing due allowance for energy stored in or lost from the body during the feeding period. It was decided to use young lambs in this work and to carry the fattened lambs to a desirable market weight of approximately 90 pounds. In the spring of 1925 the required number of grade lambs, about three months of age was available, and accordingly on April 16 six of these lambs were killed and subsequently analyzed. These were to constitute the check group. The ration chosen consisted of equal parts of alfalfa hay and corn. Two other groups of lambs were started on maintenance and fattening rations, but they did not eat well. They did not adapt themselves to the system of individual feeding, probably because they were too young, and the experiment was therefore dis- continued. In the fall of the same year some lambs were obtained from an Oregon ranch. They were a mixed group of ewes and wethers, dropped by western ewes bred to purebred Hampshire rams. At the time the experiment was resumed in September, they were from five to five and a half months old. On September 21, eight of these lambs were slaugh- tered and analyzed as a check group; another group of eight was fed a ration of alfalfa hay and corn in equal parts for maintenance of weight, while a third group of nine was fed for fattening on the same ration. The lambs were fed individually in all cases. The individual feeding of these lambs was successful. The main- tenance group was on feed until the early part of February or March, the final date varying for different individuals. During this period metabolism and digestion trials were made upon each of the eight lambs. At the termination of the period of experimental feeding, the lambs were slaughtered and analyzed. The lambs in the fattening group were fed until weights approxi- mating 90 pounds were reached, when they were slaughtered and ana- lyzed. Two of the lambs were slaughtered on December 21, 1925, five on January 5, 1926, one on February 9, and one on February 18. Di- gestion and metabolism trials were made upon only five of the nine lambs in this group. The pen in which the lambs were allowed to exercise was approxi- mately one by five rods. The lambs were fed in individual feeding crates located in a shed open toward the south. Water and salt were provided ad libitum. Except at feeding time, the lambs were allowed the run of the open pen. Body weights were taken weekly, and all feed used was sampled continuously and submitted to a routine chem- ical analysis, including the determination of calcium and of the heat of combustion. The carcass samples also were analyzed for calcium and gross energy. THE MAINTENANCE AND FATTENING OF LAMBS 33 CHEMICAL COMPOSITION OF CHECK LAMBS Altho the results of the analysis of the first group of check lambs were not used in the later computations of the experiment, they are nevertheless reported because of their interest and importance as rep- resentative of the composition of lambs three to four months of age. Two samples were prepared from each lamb for chemical analysis: ll) a carcass sample prepared from one-half of the dressed carcass, including one kidney; and (2) an offal sample, including the blood, head, skin, and feet, visceral fats, and all viscera except the kidneys. A composite wool sample for the group of six lambs was also analyzed, the lambs being shorn before slaughter. In preparing the two samples the different tissues were ground separately according to convenience and ultimately mixed together thoroly. The slaughter data, the total weights of lean, fat, bone, offal, and wool, and the percentage composition of the chemical samples from the first group of grade lambs will be found in Tables 1, 2, and 3. The estimated percentage composition and gross energy content of the lambs, on the basis of the live weight as well as of the empty weight, are given in Table 4. About a year before the first group of check lambs was slaugh- tered, advantage was taken of an opportunity to analyze a number of new-born lambs that had died from unknown causes a day or two after birth. Four of these new-born lambs were of average weight or better and appeared normal in every respect. The first two were pre- mature, having been dropped about ten days before the termination of the normal gestation period. They were subnormal in weight and composition. Since these analyses have not heretofore been published, they have been summarized in Table 5. They possess the same gen- eral significance as the analysis of other groups of lambs reported in this bulletin. The second group of check lambs, used in the computations of this experiment, was slaughtered and analyzed according to the same scheme as the first group, the samples being composited in exactly the same manner. The results obtained are summarized in Tables 6. 7, 8. and 9. These western lambs were in somewhat poorer condition than the younger grade lambs killed in the spring of 1925. Another noticeable difference between the western and the grade lambs relates to the ash content. The western lambs contained 4.79 percent of ash on the basis of the empty weight, while the grades contained only 3.32 percent. The calcium made up approximately the same percentage of the total ash in each group, i.e., 28.5 and 27.4. The greater ash content of the west- ern lambs may be traced definitely to their greater bone content. No weights on the total skeleton are available, but the bones in the dressed 34 BULLETIN No. 314 [August, TABLE 1. SLAUGHTER DATA FROM FIRST GROUP OF CHECK LAMBS (All weights in pounds) Lamb No 1 21 25 12 22 30 Average Live weight 47.4 50.1 47.8 54.4 50.9 49.7 50.1 Wool 1.76 1.65 1.08 1.71 1.54 1.11 1.48 Blood ... 1.94 2.19 2.25 2.19 2.31 2.38 2.21 Skin and feet 4.44 4.56 4.56 4.38 5.13 4.69 4.63 Caul fat .56 .56 .50 .56 .19 .44 47 Gut fat .31 .31 .44 .56 .75 .44 .47 Contents of first three 6.25 4.63 6.38 6.06 4.31 4.69 5.39 Contents of 4th stomach 2.44 2.06 2.13 1.38 1.75 1.31 1.85 Contents of entire 8.69 6 69 8 51 7.44 6.06 6.00 7.23 Warm dressed carcass. . . Cold dressed carcass 20.81 20.05 3.65 25.38 24.85 2 09 21.06 20.90 76 27.31 26.53 2 86 24.50 23.50 4.08 24.25 23.50 3.09 23.89 23.22 2.76 18.3 13.3 17.8 13.6 11.9 12.1 14.5 Dressing percentage 42.7 49.6 43.8 48.8 46.2 47.2 46.4 TABLE 2. WEIGHTS OF SAMPLES ANALYZED FROM FIRST GROUP OF CHECK LAMBS Lamb No. Empty weight Dressed carcass composite Offal Wool Lean Fat Bone Total 1 kgs. 17.58 19.69 17.81 21.30 20.35 19.84 19.43 grams 5 988 7 352 6 035 7 672 6 876 6 748 6 779 grams 1 391 2 035 1 432 2 286 1 706 2 Oil 1 810 grams 1 736 1 722 1 783 1 998 2 028 1 808 1 846 grams 9 115 11 109 9 250 11 956 10 610 10 567 10 435 grams 6 740 6 730 7 140 7 161 7 561 7 224 7 093 grams 798 748 490 776 699 503 669 21 25 12 22 30 Average.. . TABLE 3. PERCENTAGE COMPOSITION AND ENERGY VALUE OF SAMPLES ANALYZED FROM FIRST GROUP OF CHECK LAMBS Lamb No. Dry substance Crude protein Ether extract Ash Calcium Calcium in percent of total ash Gross energy per grams Carcass composite samples 1 44.04 17.11 21.23 5.21 1.85 35.5 sm. cals. 2 866 21 48.32 16.32 24 77 4 62 1 46 31.6 3 088 25 43.47 18.26 19 62 5 22 1.72 33.0 2 746 12 53.56 15 95 26 74 3 55 99 27.9 3 306 22 44.02 16.87 22 15 3 90 1.28 32.8 2 897 30 44 74 16 46 23 32 3 55 1 01 28 5 2 951 Average. . . . 46.36 16.83 22.97 4.34 1.39 31.6 2 976 Offal samples 1... 32 . 08 16 89 12 10 2 47 59 23 9 1 969 21 34.31 16.88 12 79 1 85 47 25 4 2 086 25 29.76 17 07 9 93 2 10 48 22 9 1 780 12 32.70 16 06 12 22 1 83 40 21 9 2 112 22 . 28.93 16 37 52 1 89 39 20 6 1 760 30 28.94 16 44 9 58 1 94 41 21.1 1 743 Average 31.12 16.62 11.02 2.01 .46 23.5 1 908 Composite wool samples 1-30... 91.89 70.75 13.75 7 47 .28 3.75 4 938 1928] THE MAINTENANCE AND FATTENING OF LAMBS 35 TABLE 4. PERCENTAGE COMPOSITION AND GROSS ENERGY CONTENT OF FIRST GROUP OF CHECK LAMBS Lamb No. Dry substance Crude protein Crude fat Ash Calcium Calcium in percent of total ash Gross energy per gram On basis of live weight 1 32 11 15 15 13 29 3 25 98 sm. cals. 2 013 21 36 80 15 32 16 37 3 08 86 2 290 25 30.46 15.00 11.95 3.09 . 90 1 870 12 38 33 14 63 16 94 2 47 80 2 370 22 32 47 15 24 13 72 2 64 72 2 059 30 32.27 14.. 54 14.32 2 44 .61 2 050 Average. . . . 33.74 14.98 14.43 2.83 .78 2 109 On basis of empty weight 1. .. 39 30 IS 54 16 27 3 98 1 20 30 2 2 465 21 42.46 17.67 18.82 3.56 1.00 28 1 2 643 25 37 06 IS 25 14 54 3 76 1 09 29 2 276 12 44.41 16 95 19 63 2 SB 70 24.5 2 746 22 36.86 17.30 15 58 3.00 ,82 27.3 2 338 30 36 69 16 53 16 28 2 77 70 25 3 2 331 Average. . . . 39.46 17.54 16.85 3.32 .92 27.4 2 467 TABLE 5. PERCENTAGE COMPOSITION AND GROSS ENERGY OF XEW-BORN LAMBS Breeding Birth weight l Dry substance Crude protein Ether extract Ash Gross energy per grams Ibs. 6 18 99 11 38 2 32 2 35 sm. cals. 1 Oil 7 18 04 11 19 1 SI ' (is 882 9 75 23 02 14 94 2 S2 3 36 1 148 10 7 23 32 15 44 2 SS 3 02 1 30S Southdown 6 6 24 69 15 19 2 76 3 S4 1 324 Southdown 7.2 22 66 16 44 2 44 3.35 1 236 Average 2 23.42 15.50 2.72 3.39 1 254 'Sixteen Southdown lambs dropped from ewes in the University flock during the same year averaged 7.7 pounds in weight at birth; 24 Rambouillet lambs averaged 9.7 pounds. Exclusive of first two lambs. TABLE 6. SLAUGHTER DATA FROM SECOND GROUP OF CHECK LAMBS (All weights in pounds) Lamb Xo 156 29 64 44 83 7> 80 81 Aver- age Live weight 59 7 60 6 5s 4 60 6 57 4 5S 1 58 6 Wool 3 38 3 38 2 81 3 06 3 69 ' ti3 3 13 3 13 3 15 Blood 3 44 2 81 2 63 2 25 2 7.") 3 00 2 r:> 2 63 2 7s Skin and feet 6 38 4 75 5 38 4 SI 5 (ID - 5 19 5.38 5.34 Caul fat . 25 69 3s 81 44 ."id 56 38 .50 Gut fat 56 44 56 50 44 44 44 44 .48 Contents of first tin 5 19 6 81 4 81 5 31 9 81 6 56 6 06 5.69 6.28 Contents of 4th stomach 4 31 3 13 3 06 2 50 3 56 2 88 2 69 2 44 3.07 Contents of entire alimentary tract Warm dressed carcass. . Cold dressed carcass .... Percent shrinkage Percent "fill" 9.50 26.19 25.61 2.21 15 9 9.94 28.19 27.60 2.09 16 4 7.87 27.94 27.20 2.65 13 7 7.81 27.56 26.86 2.64 13 3 13.37 26.25 25.49 2.90 22 1 9.44 26.38 25.68 2 ..65 16 4 8.75 27 . :>!> 26.66 3.27 15 1 8.13 8 ! 3.28 14.6 9.35 26.99 26.27 2.70 15.9 Dressing percentage. . . . 42.9 45.6 47.3 46.0 42.1 44.8 45.9 44.9 36 BULLETIN Xo. 314 I ss .i;ed 1.846 grams for the grades and 2.588 grams for the western lambs, which is equal to 9.52 and 11.61 percent respectively the empty weight and 11.45 and 13.52 percent of the fat-free empty weight. TABLE 7. WEIGHTS OF SAMPLES ANALYZED FROM SECOND GROUP OF CHECK LAMBS Lamb ;. Empty Dressed - - - -' Wool :.'. Fat Bone 1 !' ' ii 1 22 -- 22. 97 22 : 22 7 21.41 21.75 22.4 21. ( 22.30 - ' 413 1 -; . . ,- ] L7 - B - ' r 896 : _ K ' 616 - : 92 1 441 ' ". 1 133 1 130 1 211 1 000 1 349 - 858 2 . 2 641 2 523 2 < 2 646 2 543 . 588 11 453 12 047 9 ' 78 I 11 3.50 2 11 7i 10 342 11 553 - - 852 - 7 571 " 617 7 ; - 7 7 - 7 886 - . ' 1 .533 1 533 1 27i ; 388 1 674 1 193 1 420 1 - 1 430 . 44 S3 ... . -- - 51 ' : - ...- Exclus f I ies of 1 I and feel TABLE S. PERCENTAGE C< - fa < ION AND ENERGY VALUE OF SAMPLES ANALYZED FROM SECOND GROUP OF CHECK LAMBS Lamb , - pro- : - - Calcium in percent . C per trr mposite san.: 156.. .. ' - - Z - - - ti .. 17 17 1 7 17.31 - - - - ~ ; _ - - - - - - 7 - 7 1 - - ; ' 1 ! 4.77 - - 5.90 5.90 .- ' 1 - _ 1.56 _ _ 1.99 1 ~ 1 2 34.4 - J - 3.3 . 7 caii. 2 - ' - _ ^ - 177 ^ 2 691 \ - Offal samples 156 27 7 i i 30.26 - - - 16.44 7.32 12.63 13.15 9.60 11.14 9.91 10.36 i ii ii . .71 _ 88 77 - .71 K 23.1 . ! 2 24.6 - 25.0 24.5 J7 2 005 1 701 2 - 1 77- 1 914 1 71- . - - 78 - - Composite wool sample Entire group 91.57 70.19 6.47 10.88 .28 2.57 4 563 : - THE MAINTENANCE AND FATTE> - TABLE 9. PERCENTAGE COMPOSITION AND Gr;< .-- I : NTENT OF SECOND GROCP OF CHECK LAMBS Lamb Dry Crude : Xo. substance pr- . :ract Ui - - ri Gross '- sram 1 . M . reigfat 156 . 31 66 16.66 16.42 12 12 - 13.04 LS.84 14.75 16 . 02 10.95 11.37 17.06 11.41 16.96 16.40 11.90 4.73 32 3.45 4.34 3.49 ; 21 ; 3.99 - 2 1.32 1 . _ _ 2 - .01 1.14 ', ','.', .' ','', / i - o; *. to co2s. i \ . 17 - - I 851 1 909 1 : a - 1 171 29 ... 34 73 64 33.74 44 35 OS 83 . 30 9>, 78 ... . 32 54 80 ?.3 33 81 . -, Average 33.09 _ . | - - gfai 156 37.64 19.81 11.51 19.64 L8.7S 15.10 18 . 29 L7 . 02 14.11 19.17 13.61 20.09 13.44 1 - _ 19.52 14.15 ! - 1 S7 1 ' 1 18 ' - 9S 1 - - 4.79 : ^ - 1.45 >7 1.43 3 18 1.36 2 1 1 2 V ' _ ' 2 581 . -' _ 284 2 274 2 2li 2 346 29 41.54 64 39 09 44. 10.49 83 " 78.. 5.8J 39 24 81 S.24 Average 39.37 MAINTENANCE EXPERIMENT The feeding of the eight maintenance lambs started on October 10. 1925. Their weekly weight.- from this ".mil February 6 or 13 are given in Table 10. TABLE 10. WEEKLY WEIGHTS OF LAMBS DURING MAINTENANCE FEEDING PERIOD* - ' : ~ Lamb Xo 10 11 - . - 136 _ Oct. 10 65 63 65 - 63 i 17 . - ' i 61 61 24 ] j 66 65 - 31 64 65 65 fifi 65 _ Nov. 7 72 69 ' 69 1 - J 14 - 69 66 64 - 21 69 ~ 71 ~ 69 28 67 - 70 69 66 64 Dec. 5 - 66 J 71 1 i 69 12 1 J ' - - 19 66 65 a 66 66 - - 69 - -_ 71 n - Jan - ' 70 73 i 74 70 73 9 70 - n - j | 69 16 69 71 -- j -I - - 23 71 74 - 74 73 - 30 71 73 J ' 73 - Feb. 6 73 79 77 :: n 1 - . 13 76 -' Final weight .... 69.4 73.2 71.7 71.6 74.9 69.0 n i '- - Average weight . 68.2 69.2 70.6 J 69.3 67.1 70.6 66.5 'Xo. 136 was slaughtered on Fei>: . -. N : - : . . . " - and Xos. 11 and 43 on March 4. Some of the weekly w, j ;1 from the table and from the averages because of irregularities incide:.' 38 BULLETIN Xo. 314 [August, Body Weight Changes The weight records in Table 10 indicate that the feeding was ap- preciably more liberal than a maintenance ration. All lambs increased in weight slowly. They were started on .8 pound of alfalfa hay and .8 pound of corn per head daily. On November 21 this allowance was decreased to .7 pound of each feed daily for all of the lambs except Nos. 75 and 136. The same reduction was made for Lamb 75 on No- vember 28; Lamb 136 was carried thruout at the higher level. The chemical composition of the different samples of feeds collected at the sheep barn and at the Nutrition Laboratory, where the metabolism tests were run, is given in Table 11. Results of Digestion and Metabolism Trials In the last few weeks of the experiment each of the maintenance lambs was subjected to a digestion and metabolism trial during which feces and urine were quantitatively collected for 10 days. In each case the lambs had been consuming for several weeks prior to the collection period a constant daily amount of feed, the same as that consumed during the time of collection of excreta. The excreta passed during the first day in the metabolism crate were rejected. The meta- bolism crates used have been described in Bulletin 283 from this Sta- tion. The coefficients of digestibility for the different nutrients, com- puted according to the ordinary method, have been summarized in Table 12. In addition to the routine analyses of feed and feces, the gross energy was also determined in these samples, as well as in the urine, by combustion in the bomb calorimeter. These determinations per- mitted the computation of the metabolizable energy in the mainten- ance rations (Table 13). The nitrogen balances of the lambs during the metabolism trials are shown in Table 14. All lambs were storing nitrogen. An average of 59.7 percent of the gross energy of the ration was metabolizable. Armsby has computed 1 from his own experiments on steers that the gross energy of alfalfa is 44 percent metabolizable and that of corn 75 percent metabolizable. For a ration containing ap- proximately equal amounts of gross energy from these two feeds, as was true of the ration fed the maintenance lambs, one would expect with steers that 59.5 percent (average of 44 and 75) of the gross energy would be metabolizable, a value practically identical with the average percentage actually obtained with the maintenance lambs. Forbes and associates have recently reported 2 some energy metabolism studies on two steers receiving a ration containing equal parts of alfalfa 'Arinshy, H. P. Tho nutrition of farm animals, 661. Macmillan. 1917. "Forbes, E. B., ct al. Amer. Soc. Anim. Prod. Proc., 1927. 1928} THE MAINTENANCE AND FATTENING OF LAMBS 39 (iross energy per gram ~ c: t- < i.e rr. S -r J) -r Z . 'S '" ~ x ~. 5 c c^ i -C a ~- ~ ' ': ' T x ^* i^- d -o : o IIIII:K ,>s 03 X c s. ! . . EH H a -: x r: x -t 5; X :S o^re-t- X o ri us NANC 5. r- r- b- -,c ce \ 1 i- i; x cr. ?1 ce M re s; re M IN O H a a ~ ~~ re re re re re E a ii X; "~e CT: f~ r- X - < x -r M M re x t~ 'c 'C HV.IS.S. i - ~ - -0 7^ 7j re c*i 7 1 ! o c O Q r t > 2 _ re c-i re . ri = ~ -r -r ^r -r re SSE2 I ic O i = g'S ^; re c: X ~ 7* 2S7!qs i "E r. r 1 " i -i i-e - re X C5 ~ c: X 1 i s ^ ^ c 1 o o | X=!5S3^ = re t; -r *? -^ s w H G "1 SSSSS x x r^; * x O ID re 1. TABLE 1 Description of feed sample i'i^'C'u I''ed at barn Metabiilism trial 1 . . Metabolism trials 2 . . Metabolism trials 3 . . l'Vd at barn re t_ i| H 2~ = n o "3 Q ='-? S u ^ "T>I ^ ^ o L =i ! j3 ^ ^ t~ ^ 'These sai metaboliam trial 40 Buiuocr Na 3M .-'--" ~ - " - - - LAMBS rita - MM - proteia - Crud - - - ft ' !** fwnri. - 1 - sa ' -. ' - - - " 60 ~ " - - ". - " ~ ! gj - " ] 53 - 59 - - " - i -- : - gross maintei cioi . .' ' - , t. These 1 ~ sely with thos - Di:".v Iz:^ke c: Feed and E~ergy i ring the main 1 \ r 100 - ~ .. .. _ : " r - i Q to 1 100-: . . * : to 100 and i ; :. - ~".~ ::.e ral -thini: f the weight of i tot two-thirds 100. _ body =ize with i :o i - tsm v the 1 met - - _ mus - . - . . _ . . . _ - - 2 st g horizontally Since :he A.r.-enanre of these lambs involved both the . - is th< " : T . _ " ould be eriod - . - kings e ob- tained only by ; v;^r.:ering and analyzing the maintenance lambs and comparing '.heir : r.'.-rr.: o: energy with that of the check lambs, which , - . - . \ Composition of the Maintenance Lambs iin- tenance lan'r - ir- given in Tables 16. 17. 18. and 19. "With this group - -. * - ----.'-- -_;- r : - ~ ? '_ ^ _: : - ; Jt -.- - - ------ Z . ^ - - - r - - : 5 s 5.. 5 = .-------; .- 5 1 = --.-.-.--.-.- - . - ^ . _. . _ . _ _ -- " - s z = " z - - ~ ~ _ 2 : r " C I " 3 = - - - - : - . ;=-c-r-r r' * .-_ ^ - _ - ; _ _- _ - ^ -~- L - ~ ~ ~ ^ ~ ' ~. ----- . - - : - - - : ; ' 42 BULLETIN No. 314 [August, 1 co o co oo (N O CO CO (O * ^-H 050 !r> co o> oo oo co i-i CN rH > OOO-H K3 "5 N CN T)< CO (Nl> COOO CO SS&&3- C ^ CNCN coSSSS ^ ^ 00 T-l O 10 10 -H r-l CO b* Oi O5 O5 ' *^ CN N OOOOO I-IT)< O>CO INOS oro t~ iHf. CO CO CO 1-H M rt ^^ rH rH >oirao>o COCOCOl^Tfl OOO t^O * ^SooS"" 1 C> '~ t IN N o >o 10 >o iccc cooo tO Tl" rH IO Tjl 000 Ng CN Sg8- ^^ CN-H -t- I 300 O .. coo INN (NCOCOt^TjH ^H 00 .00 COCO rH T)< 1-100 i-l "" TfllH 1C O O CO < 00 U3 1C 1-1 r-l (Ni-i So "Og-B-ooo.-.S; :S^:2l2-gJ ;^|,a|aa|ig g g ^.2-2 ^.2-2 l!a-glgg-2ss a8^i-2-ssi ft - g li-i-ilsg^;^ agss'gYj'g'si'S Sa.S?SP"-S^^^ " 3 = Ca)SS_aiO)ft E" ft ft OM^P^MMgg^gg ? 2"3"3 0^.^00=500 &^^H^OO|00 C<;HH S 1928] THE MAINTENANCE AND FATTENING OF LAMBS 43 TABLE 16. SLAUGHTER DATA FROM THE MAINTENANCE LAMBS (All weights in pounds) 136 85 75 22 10 25 11 43 Aver- age Live weight 72.8 72.4 69.0 71.7 69.4 71.6 73.2 74 9 71 9 Wool 2 80 4 00 3 90 5 25 4 50 6 65 4 75 4 91 4 60 Blood 2.80 3.25 4.10 3.70 2.90 3.20 3 00 3 17 3 27 8 50 7 20 5 70 6 50 5 15 6 35 6 66 6 83 6 61 Caul fat. . .80 1.60 1.50 1 55 1 35 1 75 1 69 1 46 1 46 Gut fat .80 1.10 1.35 1.25 1.40 1.10 1 24 1 02 1 16 Contents of first three 5.15 5 15 4.70 5 40 3 65 5 05 5 29 5 45 4 98. Contents of 4th stomach 3 90 2 55 3 05 2 55 2 00 2 15 3 07 3 40 2 8$ Contents of entire alimentary tract Warm dressed carcass. . Cold dressed carcass .... Percent shrinkage 9.05 37.00 36.08 2.49 7.70 37.50 36.90 1.60 7.75 35.50 34.60 2.54 7.95 35.75 34.86 2.49 5.65 39.50 38.91 1.49 7.20 37.25 36.55 1.88 8.36 36.75 35.03 4.68 8.85 37.75 36.86 2.36 7.81 37.1$ 36.22 2.44 Percent "fill" 12 4 10 6 11 2 11 1 8 1 10 1 11 4 11 8 10 8 Dressing percentage. . . . 49.5 51.0 50.2 48.6 56.1 51.1 47.8 49.2 50.4 TABLE 17. WEIGHTS OF SAMPLES ANALYZED FROM THE MAINTENANCE LAMBS Lamb Empty Edible flesh Offal Wnnl No. weight Lean Fat Total 136.. . kgs. 28.94 grams 10 767 grams 2 614 grams 13 381 grams 3 998 grams 8 838 grams 1 270 85 29 34 9 989 2 960 12 949 3 970 8 155 1 814 75. 27 76 10 677 1 740 12 417 4 178 8 672 1 769 22... . 10... . 25... . 11... . 43... . Average.. 28 . 94 28.91 29.21 29.43 29.96 29.08 10 427 10 399 10 136 9 59S 9 944 10 242 2 125 4 051 3 304 3 262 3 462 2 940 12 552 14 450 13 440 12 860 13 406 13 182 4 116 3 529 3 791 4 248 4 311 4 018 8 915 7 725 8 530 8 528 8 610 8 497 2 381 2 041 3 016 2 155 2 227 2 084 three instead of two samples were taken from each carcass besides the composite wool sample for the group. The sample of edible flesh represented the lean, including the kidneys, and the fat from the dressed carcass. The bone sample included the bones of the dressed carcass and the bones of the head and feet, as roughly cleaned with a butcher knife. The offal sample contained the blood, the shorn skin, and the flesh, brain, and eyes from the head, together with all viscera and visceral fat. It is evident from Tables 9 and 19 that the carcasses of the main- tenance lambs were appreciably fatter than those of the check lambs. On the live-weight basis the maintenance lambs contained 19.25 per- cent of fat as compared with 11.90 percent for the check lambs; on the basis of the empty weight these percentages were 21.57 and 14.15 respectively. The increase in weight of the maintenance lambs thru- out their feeding period increased still further the storage of energy in their bodies. Evidently the ration fed was appreciably greater in energy value than the lambs required for the maintenance of energy equilibrium. An attempt to correct the ration fed to energy equili- brium has been made in Table 20. 44 BULLETIN No. 314 [August, TABLE 18. PERCENTAGE COMPOSITION AND ENERGY VALUE OF SAMPLES ANALYZED FROM THE MAINTENANCE LAMBS Lamb No. Dry substance Crude protein Ether extract Ash Calcium Calcium in percent of total ash Gross energy per gram Edible flesh samples 136... 49 53 15 38 26 68 .91 .025 2.75 sm. cals. 3374 85 49.49 15.13 27.83 .82 .027 3.29 3612 75 . 41 32 16 63 21 91 89 026 2 92 3033 22 39 61 16 56 22 57 .87 .027 3. 10 3066 10 47.36 14.88 32.03 .77 .025 3.25 3777 25. . 45 47 15 38 30 31 .79 .030 3.80 3706 11 49 04 15 00 32.81 .76 .026 3.42 3820 43. 49 24 15 31 28 63 83 023 2 77 3551 Average. . . . 46.38 15.53 27.85 .83 .026 3.16 3492 Bone samples 136 60.79 59.90 58.66 58.24 57 . 84 60.40 55.74 57.74 58.66 19.17 19.52 19.51 19.38 18.96 19.38 18.02 19.31 19.16 - 17.96 19.77 18.44 17.31 16.71 20.86 19.77 18.59 18.68 20.90 18.78 18.64 18.73 19.55 18.21 16.41 18.35 18.70 7.84 7.09 7.03 7.00 7.33 6.72 6.14 6.99 7.02 37 . 5 37.8 37.7 37.4 37.5 36.9 37.4 38.1 37. 5 2862 3115 2905 2781 2679 3092 2816 2802 2882 85 75 22. 10 25 11. .. 43 Average. . . . Offal samples 136 31.89 35.99 36.53 35.99 43.01 38.94 39.08 36. 3S 37.23 15.2.5 15.25 13.19 13.81 14.38 14.56 13.94 15.00 14.42 15.51 18.43 21.04 18.74 21.50 20.51 21.21 18.04 19.37 .91 1.09 .97 1.09 .99 .94 .98 1.05 1.00 .026 .030 .035 .023 .034 .026 .022 .029 .028 2.86 2.75 3.61 2.11 3.43 2.77 2.24 2.76 2.82 2319 2650 2674 2639 2914 2889 2811 2524 2678 85.. 75 22 10 25 11 43... 1 Average. . . . Wool samples 136-43 91.57 60.63 8.60 11.6 .177 1.53 4460 Changes in Energy Content of the Maintenance Lambs The carcasses of the maintenance lambs contained an average of 89.9 therms of gross energy. Assuming that their energy content at the beginning of the feeding period was the same as that of the check lambs at slaughter, i.e., 894 calories per pound, the initial energy con- tent of the maintenance lambs may be estimated; this has been done in Table 20, giving an average estimate of 56.4 therms. Hence during the period of feeding, the maintenance lambs added some 33.5 therms of gross energy to their bodies at the rate of 252 calories per day. The daily ration therefore provided 252 calories of net energy in excess of the maintenance requirements. It may be estimated from Armsby's data 1 that the metabolizable energy of a ration consisting of equal 'The average gross energy of the alfalfa hay consumed by the maintenance sheep was 4,108 calories per kilogram and that of the corn, 3.986 calories per 1928} THE MAINTENANCE AND FATTENING OF LAMBS 45 TABLE 19. PERCENTAGE COMPOSITION AND GROSS ENERGY CONTENT OF THE MAINTENANCE LAMBS Lamb No. Dry substance Crude protein Ether extract Ash Calcium Calcium in percent of total ash Gross energy per gram On basis of live weight 136... 39.47 41.42 39.55 39.19 44.73 44.61 42.07 41.97 41.63 14.96 15.75 16.29 17.05 16.42 18.09 15.62 16.26 16.31 17.46 18.76 17.48 16.65 22.42 21.17 21.23 18.79 J9.25 3.58 3.53 3.77 3.85 3.54 3.78 3.40 3.68 3.64 .97 .88 .97 .92 .85 .82 .81 .91 .88 28.0 24.8 25.5 23.6 23.7 21.5 23.6 24.5 24.4 SOT. cals. 2 504 2 754 2 586 2 583 3 039 3 068 2 849 2 688 2 759 85 75 22 . 10 25 11 43 Average. . . . On basis of empty weight 136 45.06 46.35 44.56 44.08 48.69 49.59 47.51 47.60 46.68 17.08 17.62 18.36 19.18 17.87 20.11 17.64 18.44 18.29 19.93 20.99 19.70 18.73 24.40 23.53 23.97 21.31 21.57 4.09 3.95 4.25 4.33 3.85 4.20 3.84 4.17 4.09 1.11 .99 1.09 1.03 .93 .91 .92 1.03 1.00 2 859 3 082 2 914 2 905 3 308 3 410 3 217 3 049 3 093 85 75 . ... 22 10 25 11 43 Average. . . . parts of alfalfa hay and corn is 53 percent net available. Forbes and associates (loc. cit.) have more recently investigated directly the utili- zation of the energy of this ration on two steers. From the data ob- tained it may be computed that the metabolizable energy equivalent to one-half the maintenance requirement of steers, when added to a main- tenance ration, increased the energy balance by an amount equal to 55.4 and 55.7 of the added metabolizable energy. In other words, be- tween a maintenance level of feeding and a level 50 percent higher, the metabolizable energy appeared to have a net availability of a little over 55 percent. This percentage is in close agreement with the value obtained from Armsby's data and has been used in the calculations of Table 20. Corrected Maintenance Requirements Assuming, therefore, that the metabolizable energy consumed by these lambs above their maintenance requirements possessed a per- kilognim. Of the gross energy of alfalfa hay 44 percent is available as metaboliz- able energy, and of corn 75 percent is available (see page 38). Of the metaboliz- able energy in these feeds the percentage available as net energy for fattening is (Armsby, "The Nutrition of Farm Animals,'' page 661) for alfalfa hay 39 percent and for corn 61 percent. Each kilogram of alfalfa hay therefore, contained 4,108 X .44, or 1,808 calories of metabolizable energy, and 1,808 X .39, or 705 calories of net energy: and each kilogram of corn contained 3,986 X .75, or 2.900 calorics of metabolizable energy, and 2,900 X .61, or 1,769 calories of net energy. The aver- age net availability of the metabolizable energy of a ration containing equal parts 705 + 1,769 of these two feeds is therefore 1,808 + 2,900 = 52 - 55 46 BULLETIN Xo. 314 [August. Average O OTiS IS CM T CM CO to O T iverage gross it was found nance lambs, nergy intake, ed energy. g is t- >-* t- ?1 3 30 is CO T t- iS O cote t~iO iS X x' ft CCO p had. The nance sheep y the mainte etabolizable < valent of sto iO X O T CO O C X 01 iO b- iO O CO b- OS >O CO IS T IS T b- CO b-o i.o -r le check shee of the maint consumed b s the daily in e energy equ iO -H ocoo ' r- O O T TX iS M CO O X iS M X X 'S T iS CO COM M X T i.O M CM X O e weight as t ibolism trials 1 gross energ; by .filtS givi inetabolizab CO CO CO T S: iO is" O CX IS TO c; is co r~ T o uo iS M T C1CO C: iO M CO kilogram liv uring the met y. The tola n multiplied gy intake les> .0 M O OC e os o o -HO is T CO t S: iO T IO i.O O is CO iS f~ X CO ' x s-. o O CO M ~ " 5 'f. r IN N S T X O iO X is C! CO h- X iO M iO O i-O O iS CO ~OT the same gn S(t4 calories p ble as metal) >f gross encrg 'Daily ineta = iS ~. T X C T is p O iO i.O t i > 1 M O 'O ~ '-; t; '3 ~ '3 ' *~< i-O CM 1*0 >0 X -H CO CO O 'S CO p at their initi er kilogram of li energy consun lent gives the bolizable energ c. 3 : ; a c O fc .0 Feeding period, days Average body weight, pounds dross energy content, the! ins Final Initial' ( lain Daily intake of metabolizable energy calories 2 Daily storage of energy, calories. . . . Assumed availability of metabolizabl energy of the ration, percent Metabolizable energy equivalent of t stored energy, 3 calories Maintenance requirements of metalx energy daily, calories Per bead* J'er 100 pounds live weight: Weight ratio Surface ratio Maintenance requirements of ration,! per 100 pounds live weight: Weight ratio Surface ratio 'Assuming that the niaintenan energy of the check sheep was 1971 ci that an average of 5!).S percent of tl divided by the number of days on 8 Daily energy storage divided by . . r >5 192S] THE MAINTENANCE AND FATTENING OF LAMBS 47 centage availability of 55, the daily net energy stored, averaging 252 calories, may be taken as equivalent to 458 calories of metabolizablc energy. The daily intake of metabolizable energy averaged 1,586 calories, so that the maintenance requirement becomes 1,586 458 =1,128 calories per head, or 1,637 calories per 100 pounds body weight computed in proportion to weight, or 1,461 calories per 100 pounds computed in proportion to the two-thirds power of the weight (body surface). The quantity of feed has been computed from these values by means of the average metabolizable energy content of the ration (1,074 calories per pound). The choice between the two estimates of the maintenance require- ment of metabolizable energy is a difficult one, depending as explained above on the proportions of energy used for the basal metabolism and for muscular activity. These are unknown. It would be expected that the more significant method of reducing these estimated require- ments to a body weight of 100 pounds would give the less variable set of values. The standard deviation of the estimates made in accord- ance with the ratio of weights is 226 calories, while that of the esti- mates made in accordance with the ratio of surfaces is 203 calories. However, the coefficients of variation are practically the same, 14.4 and 14.5 percent respectively, so that a choice between the two meth- ods on this basis can hardly be made. On a ration of alfalfa hay alone it was found in the preceding investigation with older sheep (see Illinois Bulletin 283) , that the main- tenance requirement averaged, for 12 sheep, 1,820 calories of metabo- lizable energy per 100 pounds live weight by using the ratio of weights, and 1,733 calories by using the ratio of surfaces. These figures are ap- preciably higher than those computed in the present experiment, a fact that may reasonably be accounted for by the known poorer utilization of the metabolizable energy of alfalfa hay than of corn. Net Energy Required for Maintenance Forbes and associates (loc. cit.) found that the metabolizable en- ergy of a maintenance ration of equal parts of alfalfa hay and corn was 80.8 percent net available for one of their steers (No. 47) and 81.4 percent net available for the other. If lambs may be assumed to be equally efficient in the utilization of the metabolizable energy of a similar maintenance ration, the net energy requirement of the lambs may be computed for "economic maintenance." Applying the average of the two percentages obtained with steers to the average metaboliz- able energy requirements given in Table 20 gives a net energy require- ment of 1,326 calories per 100 pounds live weight according to the ratio of weights and 1,183 calories according to the ratio of surfaces. Wood and Capstick 1 have recently calculated by an indirect matho- 'Wood. T. B., and Capstick. J. W. Jour. Apr. Sci. 16, 325. 1926. 48 BULLETIN Xo. 314 [August, matical method that a sheep weighing 100 pounds requires daily for maintenance 1.26 pounds of starch equivalent, or 1,348 calories of net energy. This value was computed in proportion to the surface of the sheep and is therefore to be compared with the estimate of 1,183 calories in this experiment. Wood and Capstick obtained their value by a mathematical analysis of data concerning the feed consumption and the variations in weight of twenty-eight sheep. The starch values of the feed consumed were apparently calculated from the average tables of Kellner for fattening steers. THE FATTENING EXPERIMENT On September 30, 1925, eight lambs averaging 66 pounds in weight were put upon such amounts of alfalfa hay and corn in equal propor- tions as they would readily clean up. On October 24 a ninth lamb was added to this group. These lambs were slaughtered at approximately 90 pounds in order to determine the nature of the gains made during fattening to a popular slaughter weight and the utilization of the metabolizable energy consumed and used for that purpose. The week- ly weights of these lambs will be found in Table 21. The average daily gains varied from .18 to .36 pound and averaged .25 pound. The feed consumption of the lambs has been summarized and averaged in Table 22. The feeds fed at the barns were sampled along with the feeds of the maintenance lambs, and the analyses of these samples have been given in Table 11. TABLE 21. WEEKLY WEIGHTS OF LAMBS DURING FATTENING PERIOD 1 (All weights in pounds) Lamb Xo 33 69 151 169 67 49 54 90 143 1927 Sept. 30 70 67 69 66 65 66 65 65 Oct. 10 69 69 73 69 55 67 69 66 17 68 71 68 70 55 67 66 66 24 65' 73 71 72 76 61 71 70 07 31 66 72 71 71 73 60 70 70 69 N'ov. 7 71 73 80 72 81 71 76 79 75 14 70 SO 77 78 78 69 78 76 72 21 73 80 78 76 78 69 75 74 73 28 73 85 77 79 80 66 76 77 73 Dec. 5 74 87 7!) 81 83 70 79 82 72 12 80 85 81 84 85 74 84 84 72 19 85 90 88 88 90 77 86 85 73 26 35 86 88 78 89 87 79 1926 Jan. 2 91 90 91 82 92 91 82 9 83 83 16 86 86 23 86 85 30 83 86 Feb. 6 85 90 13 87 17 90 Average weights 75 7 77.7 77 5 77 9 77.4 73 9 76 9 76 8 75 5 Average daily gains. . . . Length of feeding period .36 .24 .24 .'23 '.29 !l8 27 27 .'l9 in days 73 82 97 97 82 141 97 97 131 'Lambs 67 and 69 were slaughtered on December 21, 1925, after 82 days of feeding; Lambs 151, 169, 54, 33, and 90 were slaughtered on January 5, 1926, after 97 days of feeding; Lamb 143 was killed on February 8, and Lamb 49 on February 18, after 131 and 141 days of feeding, respectively. 1928] THE MAINTENANCE AND FATTENING OF LAMBS 49 ! oo^ N ro ' CD ^,' o ' -H IN co co co i i IN 00 O t^CMO I 00 J5 iO O ^H CM CM a OO-i S i-i IN 3 Z ^^.IN=; -H Z a S a 1 2?T ^ a .c * 1 H 'S TO -< 1 f < ^ 5 ^ Jl 15 CNlNTf CJ IN ooo "H CN *j 3 COXCN I t~ a S O300XCN IN 00 GC t^ < a z O TO < i-^CNCO 1-1 J CO "* * X IN TO X X CD H K O - 3 H O C T3 32 ^ e a k ll'o^f' ^^~ ~ ' o o.sfr 1 " 6 III 11^ ^3 ^^H l!5 s 5 JS - o > a 00 > > p HH 50 BULLETIN No. 314 [August, Results of the Digestion and Metabolism Trials During the period from October 29 to December 5 digestion and metabolism trials were made upon five of the nine fattening sheep. As with the maintenance lambs, the collection periods were of 10 days duration. For two of the lambs (Nos. 69 and 169) no change in feed had been made for 29 days before the collection period. For Lamb 33 the feed had been constant for nine days preceding the digestion experiment, while for Lambs 67 and 151, it had been raised from 2.0 to 2.4 pounds daily on the second day preceding the collection period. The latter two lambs should not have been put on a digestion exper- iment so soon after a change of feed, but nevertheless the results ob- tained in these cases agreed well with the results obtained upon the other lambs. Except on the final day of collection with Lamb 67, there was no refused feed in these digestion experiments. The chemical composition of samples of feed taken during the digestion and metabolism trials is given in Table 23. The alfalfa hay fed in these trials was somewhat drier than that fed at the barn (see Table 11) and somewhat higher in protein, but the corn fed was very similar in composition to the composite samples taken at the barns. In Table 24 the coefficients of digestibility of the nutrients in the ration, as computed in the ordinary way, have been summarized. A comparison of the average coefficients obtained with these fattening lambs and those obtained with the maintenance group consuming the TABLE 23. CHEMICAL COMPOSITION OF FEED CONSUMED BY THE FATTENING LAMBS DURING DIGESTION AND METABOLISM TRIALS Dry Gross Lamb No. sub- stance Crude protein N-free extract Crude fiber Ether extract Ash Cal- cium energy per gram Alfalfa hay 69, 169.. perct. 92 67 perct. 18 25 perct. 41 97 perct. 22 03 perct. 2 34 perct. 8 08 perct. sm. cals. 4172 67, 151 93 54 17 38 39 67 25 11 2 17 9 21 1 44 4215 33 93.51 17.06 43.61 22.98 2.37 7.49 1.52 4158 Corn 69, 169 88 93 8 56 73 55 2 19 3 37 1 9 6 3984 67, 151.. . 87 54 8 73 71 86 2 50 3 18 1 27 3935 33 87.56 8.56 72.09 2.23 3.54 1.14 3918 TABLE 24. DIGESTION COEFFICIENTS OBTAINED WITH THE FATTENING LAMBS Lamb No. Dry substance Crude protein N-free extract Crude fiber Ether extract 69 perct. 77 perct. 73 perct. 89 perct. 36 perct. 66 169 75 71 88 28 65 67 76 70 89 35 62 151 76 72 89 36 62 33.... 75 68 87 49 60 Average 75.8 70.8 88.4 35.4 63.0 THE MAINTENANCE AND FATTENING; OF LAMBS 51 same ration at a different level may be made by turning to Table 12. In general a higher digestibility was obtained with the fattening lambs. The determination of the gross energy of feed and excreta in these digestion experiments permits the calculation of the metabolizable energy content of the ration, the methane excretion being estimated, according to Armsby's method for steers, from the digestible carbo- hydrates consumed. These calculations will be found in Table 25. For the fattening lambs the ration contained 2.794 therms per kilo- gram of dry matter, as compared with an average of 2.653 therms ob- tained with the maintenance lambs (Table 13). For the fattening lambs the gross energy of the ration was 62.27 percent metabolizable on the average, as compared with 59.74 percent, for the maintenance lambs. The fattening lambs were all storing nitrogen during the collec- tion periods according to the data assembled in Table 26. Composition of the Fat Lambs At the end of feeding periods varying in length from 73 days to 141 days, the nine fattened lambs were slaughtered at weights of ap- proximately 90 pounds. The method of sampling was essentially the same as that followed with the maintenance lambs. For each lamb there were three samples consisting of edible flesh, bone, and offal, and for all lambs slaughtered on the same day a composite sample of wool was taken. Slight irregularities in the disposition of the bones of the head and feet, as between the bone and the offal samples, resulted thru inadvertance, but these did not affect the accuracy of the final com- putations. These irregularities are all noted in the tables. The slaugh- ter data for these lambs, the weights of samples, the results of the analysis of the samples, and the estimated composition of the total animals on the live-weight and empty-weight basis are given in Tables 27 to 30. The latter computations, as for all preceding groups of lambs, include all possible corrections for losses of moisture during slaughtering and sampling. The fat lambs contained an average ''fill" of 11.1 percent, as com- pared with averages of 15.9 for the check lambs and 10.8 for the main- tenance lambs. On the basis of the empty weight the fat lambs con- tained an average of 24.89 percent of fat, the maintenance lambs 21.57 percent, and the check lambs 14.15 percent. The average ash percent- ages for the three groups of lambs on the same basis were 4.17, 4.09, and 4.79 respectively. The percentage of calcium in the ash of the empty carcass averaged 22.3 for the fat lambs, 24.4 for the mainten- ance lambs, and 28.5 for the check lambs. The first group of check lambs also showed a high average for this value, i.e., 27.4 percent. In the case of rats, Buckner and Peter 1 obtained fairly constant percent- 'Buckner, G. D., and Peter, A. M. Jour. Biol. Chem. 54, 5. 1922. 52 BULLETIN No. 314 [August, c. 1 tH b s 1 metaboliz- able -; m 00 tC t~ t^. h- OS CDOOO'-I IN S Tjl-H IN M C5 (N ^ CO CD CO CO iO CO to I-J _o ti ^ =3^1 ^^ -Q (p -S'^' C 2 CNrfiO W O CO 5 oo w a. co o o w t^ CO t^ ^ "tl t^ PH 5S| 5 co eo co co co co en o J d 1-1 C ~ t^OOOCO'* * lO^CNiOOS 1C consun Q z 1 1 3 3 en

n 5 c 4 1< CNCNTfCO h- 3 CN X ^H 10 CO O I H^ 5 <3 CO z "S S EN iC iO * t>- U3 S- CN CN CN (N C<1 CN s V a 5 t_, < Cj M J3 1-2 J SJ 2 icoo-iot^ TJ< 6 ""COCNCOCO O) t O5t~OOOC CO t~ 5 Hfc O r . fi * M OJ CN CN CN CN *o ^< i^-iN i 03 1 w fc W *" -: ,H_ rtr -i ,_ _E H &H 03 "5 "o 2 OOGC tNCNCO t> S OCOOOO'O 00 *w -^ Tt< 1C 'O -^ Tfi 1 W 03 03 ~ Tt< ^ H '* "* t~l .0 1 IO c . 03 -3 S OJ Qj Cw 13 . TI TJI CO CC '00 CN cot^r^o co ^ T}< * ^ * CO ^ 3 & C i Jot including bones of feet, which were put in offal sample. ages of 25 to 26 thruout the growing period. The bone samples of both the fat lambs and the maintenance lambs contained normal average percentages of calcium in the ash (37.6 and 37.5 respectively). The low ash content of the bone samples as compared with that of well- calcified bone itself is to be expected in view of the imperfect separa- tion of bone from soft tissues in the preparation of these samples. 54 BULLETIN No. 314 [August, TABLE 29. PERCENTAGE COMPOSITION AND ENERGY VALUE OF SAMPLES ANALYZED FROM THE FATTENED LAMBS Lamb No. Dry substance Crude protein Ether extract Ash Calcium Calcium in percent of total ash Gross energy per gram Edible flesh samples 67 ... 51.69 13.56 36.86 1.31 .020 1 53 sm. cals. 4 196 69 51.66 13.19 35.84 1.18 .021 1.78 4 061 151 .. . 53.61 14.00 37.60 1 03 .018 1 75 4 292 169 52.14 14.56 34.23 .98 .017 1.73 4 000 54 54.19 15.56 28.60 1.07 .027 2.52 3 421 33 53.38 15.63 28 11 1 41 021 1 49 3 422 90 51.39 14.31 32.94 1.03 .020 1.94 3 794 143 48.88 15.13 33.54 .83 .021 2.53 3 968 49 .. 58.59 14.13 39.64 .73 025 3 42 4 398 Average. . . . 52.84 14.45 34.15 1.06 .021 2.08 3 950 Bone samples 1 67... 70.42 19 81 22.59 24.75 9.34 37 7 3 349 69 69.66 18.86 21.79 24.26 9.22 38.0 3 391 151 57 67 17 69 18 95 19 35 7 25 37 5 2 854 169 60 79 18.52 18.87 20.32 7.75 38.1 2 904 54 58.19 18.30 16.56 21.02 7.88 37.5 2 643 33 58 09 16 51 19 00 19.35 7 24 37 4 2 830 90 59 32 18.30 17.93 20.80 7 76 37 3 2 796 143 60.69 20.41 16.23 21.79 8.20 37.6 2 742 49 60 42 21 27 16 25 21 81 8 17 37 5 2 720 Average. . . . 61.69 18.85 18.69 21.49 8.09 37.6 2 914 Offal samples 2 67 .... 39 35 14 50 20.05 2.24 .519 23.2 2 759 69 38.06 14 . 56 17.13 2.39 .559 23.4 2 527 151 36 99 14 69 19 87 1 16 .061 5 26 2 576 169 . 37 94 14 13 21 98 1.14 .061 5.35 2 669 54 34.48 15.75 17.00 1.28 .076 5.94 2 327 33 35 99 15 50 19 08 1 31 102 7 79 2 563 90 ... . 38 46 14.69 20.63 1.14 .090 7.89 2 658 143 41.27 14.94 23.64 .92 .021 2.28 3 027 49 42 99 14 69 24 83 .95 .023 2 42 3 166 Average. . . . Wool samples 67, 69. ... 89 35 60.75 9.05 11.34 .20' 4 344 151, 169, 54, 33, 90 143, 49 89.73 89.62 60.88 60.84 8.83 8.89 15.54 14.34 .20 3 .203 4 366 4 374 'The samples for Lambs 67 and 69 contained only the bones from the dressed carcass; those for Lambs 151, 169, 54, 33, and 90 contained in addition the bones of the head; while those for Lambs 143 and 49 contained the bones of head and feet. 2 The samples for Nos. 67 and 69 contained the bones from the head and feet; those for Nos. 151, 169, 54, 33, and 90 contained the bones of the feet; while those for Nos. 143 and 49 contained only the viscera and other waste. 3 The average calcium content of a composite sample of wool from all fat sheep. In Table 30, the nine fat lambs are arranged in the order of their slaughter. No progressive differences in composition are evident, so that the data obtained do not indicate that the rapid gains are ap- preciably different in composition from the slow gains. Composition of the Gains in Weight On the assumption that the fat lambs at their initial weights possessed the same composition on the live-weight basis as the second IMS] THE MAINTENANCE AND FATTENING OF LAMBS 55 TABLE 30. PERCENTAGE COMPOSITION AND GROSS ENERGY CONTENT OF THE FATTENED LAMBS 1 Calcium Gross Lamb No. Dry substance Crude protein Ether extract Ash Calcium in percent of total energy per gram ash On basis of live weight 67... 44.10 15.01 24.14 3.56 .80 sm. cats. 2 492 69 42 74 14 82 21 82 3 56 80 2 914 151 43 14 15 00 23 37 3 61 78 3 010 169 44.43 16.10 22 47 3.82 .79 2 988 54 41.34 15.58 17.96 3.74 .84 2 476 33 41 76 15 33 18 82 3 77 81 2 582 90 42 02 14.89 21 24 3 61 .82 2 775 143 44.84 16.65 23.37 4.03 .98 3 125 49 48 49 16 10 25 78 3 70 85 3 285 Average. . . . 43.65 15.50 22.10 3.71 .83 2 849 On basis of empty weight 67 . 50 45 17 17 27 61 4 07 92 22 6 2 851 69 49 31 17 10 25 17 4.10 .93 22 7 3 361 151 48.28 16 78 26 15 4.04 .87 21.6 3 368 169 48 80 17 68 24 96 4 19 87 20 7 3 284 .~)4 . 47 48 17 88 20 61 4 29 96 21 9 2 844 33 47.61 17 48 21 45 4.29 .93 21.7 2 943 90 46.88 16.60 23.69 4.03 .91 22.2 3 095 143 49 06 18 23 25 57 4 41 1 07 24 3 3 419 49 . ... 54.22 18 01 28 84 4 14 .95 22.9 3 674 Average. . . . 49.12 17.43 24.89 4.17 .94 22.3 3 205 'Xos. 67 and 69 were killed after 82 days of feeding; 151, 169, 54, 33, and 90 after 97 days; 143 after 131 days; and 49 after 141 days of feeding. group of check lambs (Table 9), it is possible to compute the compo- sition of the gains put on during the fattening period. The results of such a calculation, expressed as percentages of the estimated increase in empty weight, are given in Table 31. The great variation among the individual estimates is due not only to the differences in the actual composition of gains but also to the not inconsiderable error in the method of estimation, according to which all of the lambs are assumed to possess the same initial composition. The average gain in empty weight from about 65 to about 90 pounds contained 75.1 percent of dry matter, 11.9 percent of crude TABLE 31. ESTIMATED PERCENTAGE COMPOSITION AND ENERGY VALUE OF GAINS IN EMPTY WEIGHT PUT ON BY THE FATTENED LAMBS Lamb Xo. Dry substance Crude protein Ether extract Ash Gross energy per pound 67 79.8 10 9 63 4 2 1 therms 3 11 69 81.8 9.2 61.2 1 8 3 03 151 73 3 9 1 59 9 2 2 83 169 73.7 12.9 53 7 2 6 2 62 54 68.8 13.5 37.6 3.0 1 89 33 70 3 11.8 41 5 2 9 2 08 90 63.3 10.2 44.6 2 3 2 15 143 71 5 15 3 52 2 3 6 2 68 49 93.3 14.0 67.8 2 5 3.27 Average 75.1 11.9 53.6 2.5 2.63 56 BULLETIN No. 314 [August, protein, 53.6 percent of fat, and 2.5 percent of ash. The computations for calcium indicated no increase in the store of this mineral. The nine lambs contained an average of 327 grams of calcium at slaughter and were estimated to have contained an average of 344 grams initially. It seems improbable that no calcium was stored during the fattening period. A slight storage, however, may have been obscured by the possible error in the estimation of the initial calcium composition of the lambs. Each pound of gain in empty weight contained on the average 2.63 therms of gross energy. This value is less than the average value of 3.25 therms given by Armsby to the energy content of a pound of gain by fattening animals, but is almost identical with the value re- ported by Wood 1 for two sheep gaining from an average of 87 to one of 124 pounds in body weight, i.e., 2.64 therms. In Bulletin 283 from this Station the average energy value of a pound of gain in empty weight from 87 to 117 pounds was found to equal 2.58 therms. Ap- parently the weight increase of sheep is remarkably constant in energy content, largely because it is fairly constant in fat content. In this experiment the average fat content was 53.6 percent; in the preceding experiment at this Station it was found to be 47.7 percent, and in the experiment of Wood it averaged 50.7 percent (on the increase in live weight). The crude protein percentages were not so constant, averaging 11.9, 13.2, and 17.6 respectively for the three experiments. Distribution of Added Nutrients in the Carcasses It is of interest to compute the distribution of the added nutrients among the dressed carcass, the offal, and the wool. Such calculations are complicated somewhat by the different methods of making up the samples for the check and fat lambs, but satisfactory results may be obtained on the assumption that the head and feet bones possessed the same chemical composition as the bones of the dressed carcass. TABLE 32. PERCENTAGE DISTRIBUTION OF GAINS IN CHEMICAL CONSTITUENTS OF THE FAT LAMBS AMONG DRESSED CARCASS, WOOL, AND OFFAL Dry substance Crude protein Fat Ash Gross energy Dressed carcass. . . Wool 66.7 s s 54.8 26 3 71.4 2 1 15.3 64 9 69.6 5 2 Offal 24 . 5 18.9 26 o 19 8 25 2 Total 100.0 100.0 100.0 100.0 100.0 The weights of head and feet bones were obtained for the fat lambs, so that the composition of the dressed carcass can be approximated. The results obtained on this question are assembled in Table 32. 'Wood, T. B. Jour. Min. Agr. [Gr. Brit.] 34, 295. July, 1927. THE MAINTENANCE AND FATTENING OF LAMBS 57 With the exception of the added mineral matter the dressed car- cass received most of the nutrient material added to the bodies of the lambs during their fattening period. An average of 66.7 percent of the added dry matter, 54.8 percent of the added protein, 71.4 percent of the added fat, 15.3 percent of the added mineral matter, and 69.6 per- cent of the added gross energy were found in the dressed carcasses of these lambs. The added wool contained about two-thirds of the added mineral matter and about one-fourth of the added protein but very little of the added energy. The mineral matter found in the wool con- tained only a trace of calcium and probably consisted of dirt to a large extent. The failure of these lambs to increase in calcium content altho increasing in mineral content is thus partially explained. The main difference in the disposition of added nutrients in the carcass between these young lambs and the more mature sheep of the preceding experiment 1 relates to the protein. In the former experiment 60 percent of the added protein was found in the wool, the growth of the carcass being largely completed. In the present experiment less than 20 percent of the added protein was found in the wool, the dressed carcass alone containing about 55 percent and the offal parts over 25 percent. With the more mature sheep, wool growth accounted for greater percentages of all added nutrients than with the growing lamb. It was also formed at a much more rapid rate, being equivalent to a daily growth of .149 pound of protein and 566 calories of gross energy per day per 1,000 pounds live weight. In the experiment on growing lambs the daily growth of wool contained an average of only .086 pound of protein and 377 calories per 1.000 pounds live weight. Utilization of Feed Energy in Fattening The relation between the feed energy consumed by the fattening lambs and their average daily retention of energy is of interest in throwing light upon the efficiency of utilization of energy by sheep. The calculations given in Table 33 are concerned with this relation. The average energy content of the lambs at slaughter was 114.8 therms. Their initial content, as computed from the initial weights and the average energy content of the second group of check lambs per unit of live weight, averaged 59.4 therms. The gain in energy therefore averaged 55.4 therms, or 568 calories, daily. The average daily intake of metabolizable energy was 2,427 calories, of which 1.254 calories were estimated to have been used for maintenance. This estimate is based upon the average weight of the lambs during the feeding period and the average metabolizable energy requirements for maintenance as previously determined, i.e., 1,637 calories per 100 pounds live weight. '111. Agr. Exp. Sta. Bui. 283, 243, Table 25. 58 BULLETIN Xo. 314 [August, a a a a z z d 5 PO a ij < U Average *^ ~ in X rl "in t "*? co x e* i IH O5 sistes CO O CO * X ^- (> ^1 M IH tH f-ll-IO ^ CO XCO-* m co -< TJ< i-l 1Q O CO ^ C^ ~H Of- CO CO OS I-H O m III" i--; < in in x 1-1 m 0) '

. ^ >n in o f- o in -r c-i -H CS i-l 1-1 S 35 _ 1- sss r- co f- '-" ^ X " a '.S ' ! : l : |^" ^ : : 1 .-" . o a ^ -"o jljlf 02 sT ^ ' " S M r ^ ||j|| Pfjl o 2 3 Final energy c Estimated init CJain in energy Average daily Intake of metsi W '-2 2 ^ ? 1928] THE MAINTENANCE AND FATTENING OF LAMBS 59 the direct ratio of weights being used. Hence, according to these fig- ures 1,173 calories of metabolizable energy may be considered as avail- able for production. The production secured averaged 568 calories daily, or an average of 48.5 percent of the metabolizable energy avail- able. As previously mentioned (page 45), experimental work with steers indicates a percentage availability of metabolizable energy of 53 to 55 for a ration of equal parts of corn and alfalfa hay. The results of this experiment point, therefore, to a somewhat less efficiency on the part of the sheep as compared with the steer in the utilization of metaboliz- able energy. For alfalfa hay alone results have been reported previ- ously for sheep (Bulletin 283) that are equal to several reported by Armsby for steers but inferior to some of the later results. SUMMARY The digestibility of a ration consisting of equal parts by weight of alfalfa hay and shelled corn was investigated at two levels of feed- ing, one representing but little more than a maintenance ration (eight lambs) and the other representing full feed (five lambs). The coeffi- cients of digestibility at the higher level were generally greater than those at the lower, altho the differences were not large. At the higher level 62.3 percent of the gross energy of the ration was found to be metabolizable, while at the lower only 59.7 percent was metabolizable. The metabolizable energy of the ration per kilogram of dry matter was 2.794 therms at the higher level, and 2.653 therms at the lower. For steers the gross energy in a ration of equal parts of corn and alfalfa hay has been found to be 60 to 61 percent metabolizable. In feeding tests upon eight lambs averaging 69 pounds in weight, the maintenance requirements in terms of pounds of feed and of metabolizable energy per 100 pounds of weight have been determined for a ration containing equal parts of alfalfa hay and corn. The data of feed consumption, feed analyses, and digestion and metabolism trials have been supplemented by carcass analyses of check lambs and of the maintenance lambs at the end of their feeding period, in order to correct for a storage of energy in the body. It was found that 1.53 pounds of feed and 1,637 calories of metabolizable energy were required per 100 pounds weight for the maintenance of energy equi- librium. These values may be compared with those determined in a previous experiment for a ration of alfalfa hay alone, i.e., 2.29 pounds and 1,820 calories of metabolizable energy. Nine lambs were used in a fattening experiment to determine the efficiency in the use of metabolizable energy for production. These lambs were fattened from about 65 pounds in weight to about 90 60 BULLETIN No. 314 pounds, at which weight they were slaughtered and analyzed. Di- gestion and metabolism experiments were run upon five of these lambs. Altho the daily rate of gain varied from .18 to .36 pound, no relation could be detected between the rate of gain and the composition of the carcass. On the average the fat content of the empty carcass increased from 14.15 percent, as determined by the analysis of eight check lambs at approximately the initial weight, to 24.89 percent. The average gain in empty weight was calculated to possess the following composition: 75.1 percent of dry matter, 11.9 percent of pro- tein, 53.6 percent of fat, and 2.5 percent of ash. Its gross energy value was 2.63 therms per pound. Altho the ash content of the lambs increased during fattening, no increase in the calcium content could be demonstrated. A small in- crease might well have been obscured by the possible error in the slaughter experiment. The absence of any indication of a large in- crease in calcium was due to two factors. In the first place, 65 percent of the increase in ash occurred in the wool, and largely represented outside contamination. Again, the percentage of calcium in the ash of the entire carcass decreased from 27.4 to 28.5 in the check lambs to 22.3 in the fattened lambs, the maintenance lambs showing an average of 24.4. The gains in nutrients by the fat lambs were largely added to the dressed carcass. Thus 66.7 percent of the dry matter of the gains, 54.8 percent of the protein, 71.4 percent of the fat, and 69.6 percent of the gross energy gained were deposited in the dressed carcass. The wool growth accounted for 8.8 percent of the dry matter gained, 26.3 percent of the protein. 2.1 percent of the fat, and 5.2 percent of the energy. The daily wool growth of these young lambs contained per 1,000 pounds live weight .086 pound of protein and 377 calories. These values are only about 60 percent as large as those obtained with larger and older sheep in a previous experiment. The daily gain of energy by the fattening lambs averaged 568 calories. The average intake of metabolizable energy was 2,427 cal- ories daily, of which 1,254 calories were estimated to have been re- quired for maintenance. The difference, 1,173 calories, may therefore be compared with the energy storage to determine the efficiency of utilization of the metabolizable energy consumed in excess of the maintenance requirements. The daily storage of 568 calories is 48.5 percent of the metabolizable energy apparently available for this pur- pose. We may say, therefore, that between a maintenance level of feeding and the full- feed level attained by the fattening lambs, the metabolizable energy of the ration of alfalfa hay and corn was 48.5 percent net available. For steers a utilization of 53 to 55 percent would be expected for this ration. fe A\ 3m ; ', DIVERSITY OF ILUNOIS-URBANA