The Effect of Die+hyls+ilbestrol and Methyltestosterone on the Growth, Carcass Characteristics, and Nitrogen Retention of Growing Swine By ERNEST W. LUCAS A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 1970 ACKNOWLEDGEMENTS I wish to extend thanks to my major professor, Dr. H. D. Wallace, for guidance and advice during the course of the investi- gation, as well as to Dr. Herb Brown of Eli Lilly and Company for supplying the hormone material and participating in the taste panel. The assistance of Drs. William Mendenhall and John Cornell in statistical analysis is also gratefully acknowledged. ! v/ish also to thank Dr. A. Z. Palmer and Roger West for their assistance in obtaining carcass data, and Bill Stradtmann for help with the Iciboratory analyses. The assistance of Mike Demaree and Jim Standish, fellow graduate students, was indispensable during the field work and collection of data. Special and deepest appreciation is extended to my wife, Barbara, for her encouragement and for typing the manuscript and drawing the figures. ii TABLE OF CONTENTS ACKNOWLEDGEMENTS " LIST OF TABLES v LIST OF FIGURES ^''^ ABSTRACT » ** I NTRODUCT I ON ' REVIEW OF LITERATURE 3 The Effects of Sex on the Growth and Carcass Quality of Swine. ............• = . = ^ 3 Sex Odor in Pork 6 The Effects of Estrogens on the Growth and Carcass Quality of Swine. 12 The Effects of Androgens on the Growth and Carcass Quality of Svnne 19 The Effects of Combinations of Androgens and Estrogens on the Performance and Carcass Quality of Swine 24 The Effects of Androgens on Protein Anabolism in An i ma 1 s 28 The Effects of Oiethylst • 1 best rol on Protein Anabolism in Animals 30 The Mechanisms ot Anabolic Action of Androgens and Diethylstilbestrol 32 EXPERI MENTAL 35 General Objectives 35 General Exper iriental Methods 35 Analytical Methods AO iii TABLE CF CONTENTS (continued) EXPERIMENTAL (continued) Statistical Methods kS Experiment I78-A '♦6 Experiment )78-B '♦S Experiment I78-C 53 Experiment ! 78-D 55 Experiments I78-E and F 58 GENERAL DISCUSS ION 61 The Effects of Hormone, Protein, and Sex on the Feedlot Performance of Growing-Finishing Swine. 61 The Effects of Hormone, Protein, and Sex on the Carcass Characteristics of Swine 6h The Effects of DES + MT en the Nitrogen Retention of Growing-Finishing Swine '^ The Effects of DES + MT on the Excretion of Urinary 17"!n *- U»*-.. « *.^.-*.— «1 *— J pd rS.r.SwSri sat. .C!^>_u ■■>.. -"'a ^5, 6^, or 32 kg. Boars and 82 kg castrates had a higher percent of lean in the rough loin, less backfat, longer carcasses, and a higlier live weiglit and lean primal cut yield. Quality of boar pork was judged unacceptable in palatability tests for odor and flavor, but no difference in palatibility of chops be- tween control barrovys and barrows implanted with testosterone pro- pionate was observed.. In this trial no differences due to testosterone or castration v;ere observed in rate or gain or feed con- version. Beeson et aj_. (1955) administered 20 mg of MT per pig per day in a practical ration to barrows and gilts fed from 23 kg to market 21 weight. Growth rate and feed efficiency were unaffected, but car- casses from testosterone fed pigs contained heavier lean cuts (ham, loin, Boston butt, picnic shoulder) and lighter fat cuts (fat backs, bellies, jowls) than carcasses from control pigs. The percentage yield for lean primal cuts was 62.'* percent for testosterone fed pigs and 58.8 percent for control pigs. Chemical analysis of carcass composi- tion showed 5 percent less fat and 5 percent more lean in testoster- one fed pigs than in control pigs. Perry et^ aj_. (1956) tested the effect of various levels of orally administered MT (O to 6?. mg of MT per pig per day) on the growth and carcass composition of grov/ing-f in i shing barrows and gilts fed from 23 kg to market weight. They reported that a daily intake of 27 mg or more of MT resulted in a highly significant growth depression, but also resulted in decreased fat deposition evidenced by decreased backfat thickness. Johnston, Zel ler, and Miner (1957) fed MT to swine at levels of 20 or 33 mg of MT per kg of feed. In 5 experiments they noted that MT decreased rate of gain, average daily feed intake, backfat thick- ness, and feed efficiency. There v.-as no odor or flavor problem reported in the meat of testosterone supplemented pigs. The authors concluded that MT increased the ratio of lean to fat in the carcasses of svnne. Whiteker e^ aj_. (1959) studied the effects of various androgens at different levels en growth and carcass traits of pigs. They fed 96 barrows and gilts in 3 trials on practical diets containing either methyl testosterone, methy landrostenediol , thyroprotein, or a combination 22 of the latter two. Rate of gain vias not significantly affected by any of these additives. Pigs fed the ccmbinat ion of methylandrostene- diol and thyroprotein produced significantly leaner carcasses than did those pigs fed cither drug singly. Pigs fed MT produced carcasses that had a significantly higher percentage of lean than did pigs fed the basal ration. None of the treatments caused an adverse flavor or odor in the meat. Loin protein content v^as not significantly affected by any of the treatments. Masculine behavior and character- istics were noted in the animals receiving MT. Thrasher et a], (1359) conducted 3 experiments to determine the effects of various testosterone analogs, combinations of testosterone and stilbestrol, and late castration on the performance and carcass quality of swine. No differences due to treatment v/ere observed in any parameter tested, although there was a trend toward increased leanness in pigs fed MT singly or in combination with DES. Baird and McCampbel 1 (1959) reported no differences in feedlot performance or carcass quality in pigs fed 0.55 mg of hydroxyzine per kg of feed. Another test comparing androgenic compounds v/ith DES , est radiol -progesterone, and a basal ration failed to show any signifi- cant differences due to any treatment. Other combinations of hormones and tranquilizer substances v;ere tested and they also failed to pro- duce any changes in grcv/th or carcasses of swine. CantVMel 1 , Johnston, and Tabler (1S62) fed sv/ine methyl testoster- one and 1 7-ethyl -1 9"riortestostcrone under various experimental con- ditions to determine their effects on growth and carcass character- istics, with special emphasis en glands and internal organs. 23 Hethyltestosterone and 1 7-ethyl -19-nortestosterone fed at 20 to 33 mg per kg of feed singly and in ccnibrnat ion with stilbestrol at 13 mg per kg of fcvid caused highly significant Increases In weight of liver, kidney, heart, and thymus gland. Average daily gain was decreased significantly, as was adrenal gland weight. The authors reported that methyl stestosterone was more potent than 17-ethyl-19- nortestosterone. Mente et^ a±, (1962) studied the effect of 9-f 1 uoro-l 1 -hydroxy- 17-iTiethyltestosterone (Halotest in) , a testosterone analog of great potency. Barrows and gilts weighing 32 to 57 kg were fed 0 to 27.5 mg of Halotestin per kg of diet. They reported a significant decrease in backfat thickness, and an increase in percent yield of lean primal cuts due to Halotestin. Gains were depressed in pigs fed the hormone compared to gains of those fed the basal diet. Hale and Johnson (1970) fed weanling pigs methyl testosterone at a level of 20 mg per day. They reported that MT decreased rate of gain, daily feed intake, dressing percentage, and backfat thickness, but increased carcass length, area of loin eye, and weight of the h lean cuts. They concluded that methyl testosterone had a potent anabolic action in swine, evidenced by the increased leanness in car- casses of pigs fed HT. The previously cited papers present a review of the effects of androgenic compounds on the growth and carcass characteristics of swine. Of all androgens in use, methyl testosterone is probably one of the most practical and anabolically potent. There seems to be rather strong evidence that MT Is capable of Inducing in swine 2h measurable carcass changes In a favorable direction. These papers Indicate that pigs fed methyl testosterone gain niore efficiently, and produce leaner, meatier carcasses than do pigs fed normal rations. There is some evidence that high level testosterone therapy may pro- duce significant odor or flavor problems in pork. The Effects of Combinations of Androgens and Estrogens on the Performance and Carca s s Qual i ty of Swine Research has indicated that there Is some benefit to be derived from feeding or implanting estrogens or androgens in growing swine of all sexes. Although changes in performance and carcass are not always great or drastic, there is nevertheless a definite trend to- ward decreased feed consumption and increased carcass leanness due to hormone therapy. Since estrogen supplementation has shown partic- ular usefulness with regard to boars, some workers feel that using the combination of androgen and estrogen in barrov;s and gilts would prove more beneficial than either compound used singly. Work has been done using combinations of estrogenic and androgenic drugs to determine if the effects of the tv.'o substances used together are ■- additive. Thrasher et_ a_l_. (1959) studied combinations of testosterone and stilbestrol and their effects on carcass quality and feedlot perfor- mance In growing -finishing pigs. In 3 trials involving a total of 1 30 pigs they reported a non-s Ignl f leant trend toward Increased carcass leanness. 25 Beacom (19^3) implanted finishing pigs with a combination of estradiol and testosterone. He observed no difference In growth rate between controls and treated pigs, but there was a significant decrease In average daily feed consumption caused by the estradiol- testosterone implant combination. Beacom also reported an Increase in lOiii eye died in Lredied pigs fed a low energy diet. Other indices of carcass leanness were favorably improved, Wallace et^ aj_. (1967) conducted a 2 x 2 x 2 factorial experiment involving protein level, sex, and supplementation with a combination of DtS and MT. The trial involved ^8 pigs which averaged 59 kg initially. The pigs were slaughtered as they reached 95 kg. Feedlot performance and carcass characteristics were studied. Hormone supple- mentation with DES + MT significantly decreased average daily gain, average daily feed Intake, and average backfat thickness. In addition, there was a significant interaction between protein level and hormone supplementation for average feed conversion ratio, which was inter- preted as evidence that hormone supplementation favored improved feed conversion in the presence of increased protein. Secondary sex glands in barrows (Cowper's gland, prostate gland, and seminal vesicles) and ovaries and uteri in gilts were markedly affected by hormone supple- mentation. All these organs exhibited hypertrophy in hornrane supplemented pigs. Loin roasts were checked for any indication of boar odor or flavor. A strong influence on odor and flavor of pork was exerted by DES + MT. The meat from some hormone fed pigs had a very undesirable odor and flavor when cooked. Both gilts and barrows were affected to the same degree. The authors concluded that the odor was probably due to methyl testosterone. 26 Baker ejt_ a_l_. (I967) fed '»'l8 finishing pigs in 3 trials to eval- uate the effects of a dietary combination of DES + MT. The effects of sex and dietary protein level on liormone response were also studied. Regardless of sex or protein level, carcass leanness was improved by DES + MT. Improved feed efficiency due to hormone, however, resulted only at higher levels of protein. These workers also observed that feed efficiency and carcass leanness response to DES + MT v/as greater in barrows than in gilts. Growth rate and feed conversion efficiency were greatest at a dietary protein level of 12 percent in barrows and l'» percent in gilts, but for maximum carcass leanness response, barrows needed 1^ percent protein and gilts re- quired 16 percent. Protein level did not appear to affect backfat thickness in any of the trials, but the remainder of carcass lean- ness parameters -were improved additively by both DES + MT and increased protein level . Baker, Oilier, and Jordan (I968) observed that DES + MT caused a lowering of serum triglycerides level v;hen fed to gilts. This de- crease did not occur in barrows. Serum cholesterol and free fatty acids were not affected by hormone treatment. The mechanism by \/hich DES + HT decreased serum triglycerides in gilts v;as not elucidated. Doornenbal and Frankenham (I969) studied growth, feed conversion ratio and chemical composition in market weight barrows and gilts fed DES + MT plus tylosin. They reported a trend toward increased gains, improved feed efficiency and a rediiction in age to market. Carcass measurements within sex were not significantly different between controls and fiormone fed animals. There v/as a trend toward increased 27 leanness in barrows, but toward increased fat deposition in gilts. The authors concluded that different proportions of sex steroid hor- mones would be required for barrows and gilts to achieve equally beneficial effects on carcass composition. Meyer et al. (1968) evaluated the effects of a dietary combina- r rM-r . ..T _- -L- J..-..;..- c. -c „:i.., fj,jJ '' 2 or k.k mq each of DES and MT per kg of diet during the finishing phase only, or continuously through finishing to breeding. A total of 136 gilts was used in 5 experiments. These workers reported that feeding the hormonal combination through breeding inhibited estrus. Some gilts conceived after termination of hormone feeding. Gilts which received the hormone only during the finishing phase had normal estrus cycles and conception was reduced in only 1 of 3 experiments. In k out of 5 experiments, DES + MT reduced litter size. It was noted that gilts fed the hormone supplement during finishing farrowed smaller litters at the first two farrowings. Litter size Increased to that of the control group by the third parturition. The authors concluded that inhibition of the normal reproductive function by DES + MT treat- ment during the finishing period did not seem to be permanent. The lower level of hormone addition was not as inhibiting to reproduction as the high level . Evidence accumulated by various researchers whose work was re- viewed in the foregoing section indicates that there may be some addi- tive performance and carcass improvement when estrogens and androgens are fed or implanted in combination. The overall trend Is much the same as that observed when either type of drug is fed or implanted 28 alone. Combining the tv.'o substances seems to produce a more power- ful stimulus to the metabolism of the animal, resulting in the changes in feedlot performance and carcass composition reported. The entire picture is unclear as yet regarding the mechanis/n of action of these po- tent humoral substances. Also, observed responses to these drugs are not always consistent in swine. it does appear, however, that '.'.■:r- there may be some benefit to be derived in feedlot performance in- crease and in favorable clianges in carcass characteristics by supple- menting growing-finishing pigs with a ccmbination of estrogen and androgen. There do not appear to be any permanent adverse effects on reproductive capacity of gilts fed DES + MT through the finishing phase. The Effects of Androgens on Protein Anabolisrn in Animals The influence of androgens on nitrogen retention has been knov/n since 1935 (Dorfman and Shipley, 1956) when it was discovered that extracts of urine containing androgenic material stimulated nitrogen retention in dogs. Drill and Saunders (195S) used rats to test the ratio of anabolic to androgen activity in a number of steroids. Of the testosterone analogs tested, l7-ethyl -l9-nortestosterone was found to be the most potent anabolically and also to have the highest ratio of anabolic to androgen activity. This compound was reported to be 5 times more anabolically active th.-.n 1 /'-a-methy! testosterone v/hen administered 29 orally to rats, while the androgenic activity of methyl testosterone was relatively high. Leathern (1956), in a rat experiment, found that the state of body protein stores at the time of hormone administration determined in large part whether or not an anabolic response was observed. Older rats and protein depleted rats exhibited a marked Increase In nitrogen retention when testosterone or other anabolic steroids were administered. Very little response in young, healthy rats fed high protein diets was observed. Leathern concluded that in many instances nutrition appears to be dominant over anabolic hormones, even though steroids are known to be involved in protein anabolic processes. Applezv.'eig (I3ii2) reported on radioisotope studies in which rats were fed ^^N-labeled glycine with and without androgen therapy. An Increase In anx)unt of ^^N-labeled glycine retained was apparent for the treated group. The author concluded that androgen influenced the reaction of amino acids ■<-♦■ proteins and caused the reaction to pro- ceed in favor of protein synthesis. He postulated that either an Inhibition of protein catabollsm or a stimulation of anabolism could be the mechanism of action. In addition, Applezv.'eig stated that when body protein stores were filled, little or no anabolic response to androgen treatment was observed. Robinson and Singleton (1966) tested the effects of norbolethone, an anabolic steroid, on the performance and body composition of barrows. They used 2^ Large White barrows fed two levels of protein with and without 0.1 mg of steroid per kg of body weight. On the low protein diet, steroid therapy increased growth, but the opposite 30 v;as true for the high protein diet. This interaction was significant, In addition, there was a significant improvement in percentage of lean in the carcass and loin eye area, but a decrease in carcass length. Evidence presented in the papers previously cited indicates that there is a definite protein anabolism in anifnals following therapy with certain steroid hormones. Response varies according to species, age, nutritional status, and sex of the animal. In general, steroid anabolism is most marked in those animals in a state of protein depletion. The Effects of Diethylst i 1 bestrol on Protein Anabolism in Animals Researchers have attempted to determine the mechanism of action of diethylst i 1 best rol in stimulating growth. There is a general agreement that increased nitrogen retention due to protein anabolism occurs in ruminants consistently, and to a more variable degree in monogastrics. The exact m.eans by which DES causes this remain un- clear. Clegg (1952) reported on the use of DES to increase nitrogen re- tention in steers. The nitrogen retention of steers implanted v/lth 60 mg of DES was more than tvnce that shown by control animals. Jordan and Bell (1952) studied nitrogen retention In lambs im- planted with 12 mg of DES. Hormone Implantation did not appear to alter digestion of feed or nitrogen retention. 31 Whitehair, Gallup, and Gell (1953) implanted lanbs with Zh mg of DES to study the effects on calcium, phosphorus, and nitrogen balance. There v^as no difference in the digestibility of feed be- tween implanted and control lambs, but DES caused a significant In-:' crease in the amount of calcium, phosphorus, and nitrogen retained. DES implanted lambs also showed faster rates of gain than control lambs. Tillman and Brethour (1955) fed lambs 6 or 10 percent protein with and without 3 nig of DES per day to study the effects on calcium, phosphorus, and nitrogen metabolism. Nitrogen retention and average daily gain were decreased by DES in the 6 percent protein ration, but the reverse was true for the 10 percent protein ration. The authors concluded that the effects of DES were not consistent. Struempler and Burroughs (1955) studied the effects of growth hormone and DES on nitrogen retention in lambs fed low or high energy and low or high protein diets. Grov;th hormone or DES alone resulted in increased nitrogen retention, regardless of dietary energy or pro- tein level. When administered together, hov/ever, growth hormone and DES did not produce an additive response. The authors concluded that DES may cause an increase in secretion of growth hormone in the animal . Sell and Balloun (I96l) studied nitrogen retention of growing cockerels as influenced by DES or MT. DES resulted in decreased ni- trogen retention, while MT did not significantly alter nitrogen balance. 32 Carew and Hill (I967) studied the effect of DES on protein utilization in chicks fed diets containing glucose or corn oil as the major energy component. Nitrogen retention v.-as markedly decreased by DES in the high fat diet at restricted levels of energy Intake, but not on the glucose diet. The authors concluded that in chicks the effect of DES on certain metabolic processes v/as influenced by the form In which dietary energy was supplied. Lasslter et_ ajl_. (1956) studied the minimum protein Intake for pigs for maximum nitrogen retention. They also Investigated the pre- cision of 3, 5, and 7 day collection periods for estimating nitrogen balance. V/ith 23 kg pigs, nitrogen retention Increased v/Ith Increas- ing protein levels up to 18 percent. With 68 kg pigs, protein levels from 10 to 22 percent did appear to affect nitrogen balance, but the difference vyas not significant. These v/orkers also reported that after a 10 day preliminary period, the 7 day collection period offered only a slight advantage over the 3 day collection period with 23 kg pigs and even less advantage with 68 kg pigs. The anabolic effects of DES vary markedly with species, age, sex, diet, and status of body protein stores, as shov/n by evidence in work cited in this section. The Mechanisms of Ps)ako 1 ic Action of An d rogens and Diethy 1 st I Ibest ro 1 The means by which certain steroid hormones and diethylst I Ibes- trol stimulate anabollsm have been the subject of Intense scrutiny by researchers as long as the anabolic effect has been known. There 33 has been no clarification of the exact mechanism by which these sub- stances stimulate protein anabolism. Dorfman (1961), at a symposium on the mechanism of action of steroids, proposed a working hypothesis for androgens which places the mechanism of action of androgens at the level of regulation of rate of biosynthesis of specific enzyme systems (protein synthesis). The action of androgen is visualized as producing the necessary criti- cal enzyme concentrations which result in growth of tissue. Androgen may act as an inhibitor of catabolism or an inducer of anabolism in this capacity. l/ilson (1962) studied protein synthesis in rat seminal vesicle tissue as Influenced by testosterone. Radioisotope ^"^C-Iabeled amino acids were used to study protein biosynthesis rate in tissue following testosterone administration. Protein synthesis v/as doubled 12 hours after testosterone administration and reached a maximum (5 to 6 fold) within 2^* to ^8 hours. There v;as evidence that this enhancement of protein synthesis vias independent of either amino acid transport or synthesis, but was secondary to the accelera- tion of a specific step in protein synthesis, the conversion of soluble ribonucleic acid - amino acid complexes to microsomal ribo- nucleoprotein. Further work should serve to elucidate more clearly the exact mechanisms involved in anabolic action of androgens. Several theories concerning the mechanism of action of diethyl- stilbestrol In stimulating nitrogen retention have been advanced by various vjorkers. The most promising hypothesis concerns the effect 3^ of stilbestrol on grov;th hormone secretion. Struempler and Bur- roughs (1S55) reported that both DES and growth hormone increased gains and nitrogen retention in lambs. When both substances were administered together, however, no additive effect v;as observed. This observation led them to conclude that DES may cause an increase in secretion of growth hormone from the pituitary gland. Davis, Garrigus, and Hinds (1970) studied the metabolic effects of DES and grov/th hormone in lambs. They also observed very similar responses to DES and grov/th hormone administration, and also concluded that secretion of growth hormone might be increased by DES. Generally, however, the mechanism of anabolic action of DES re- mains unclear. Even less is known about this substance than is known about anabolic steroids. It does appear that DES stimulates nitrogen retention more markedly and more consistendly in ruminants than in nonruminants. No direct evidence for an increase in secretion of growth hormone caused by DES has been presented, although there are indications that this may be the mechanism by v/hich DES improves growth and nitrogen retention. EXPERIMENTAL General Objectives These experiments were conducted to Investigate the effects of hormone supplementation (DES + MT at 2.2 mg each/kg of feed) and the interrelationships with protein level (12 to 161) and sex (barrow or gilt) in swine. Treatment effects were measured by feedlot performance, carcass parameters, and nitrogen balance studies. General Experimental Methods Records The experiments reported herein are on file in the Swine Nutri- tion section of the Animal Science Department, Institute of Food and Agricultural Science, University of Florida, Gainesville, Florida, 32601. Six trials were conducted between February I967 and October 1969 and the series designated as Swine Experiment 178. individual trials were numbered as Experiments I78-A through F. An i ma Is Animals used were Landrace x Duroc 2 v/ay and (Landrace x Duroc) X Hampshire 3 way cross-bred pigs. They were raised at the University of Florida Swine Unit and were fed a typical practical fortified 35 36 corn-soybean meal ration from v:eaning to tlie time they were placed on experiment. Sound management practices in raising the baby pigs were follov;ed to ensure healthy experimental animals. Male pigs v^ere cas- trated at approximately 7 to 10 days of age. All pigs had their ears notched at birth for identification and v;ere vaccinated against sv/ine erysipelas at approximately 6 weeks of age. The pigs in the first two experiments (173-A and 3) were vaccinated against hog cholera as wel I . Allotment, Feeding, and Weighing Outcome groups v;ere chosen on the basis of sex, weight, and litter, and these groups were randomly assigned to treatments. Pigs in all feeding trials were fed ad_ 1 ibi turn from sel f feeders. Pigs in the metabolism trials were ful 1 -hand-fed twice daily. Water was supplied ad 1 i b 1 1 urn from automatic v;ater fountains. All pigs were fed in confinement on concrete or steel mesh floors. All feed used was in a dry maal form. Hormone feeding was discontinued for 72 hours prior to slaughter. Feed was weighed back every 2 or 't v/eeks and a final weighback was taken at the termination of the feed- ing trial. Compositions of the diets, level of hormone supplem.entat ion, and compositions of the mineral and vitamin premixes arc shown in Tables 1 through 5- Animals were weighed initially, and at 1 or 2 week intervals thereafter until slaughter. A platform scale was used for v/eighing. 37 Slaughter Procedure and Carcass Evaluation As live weight of the pigs reached 100 kg, they were slaughtered at the University of Florida Meats Laboratory. Carcasses v;ere dressed packer style (head off) for study. All carcass weights and measure- ments were taken after the carcasses had been chilled for 'jS hours at 2" - 5** C. The length of carcass was measured from the anterior edge of the aitch bone (pelvis) to the anterior edge of the first rib. Average backfat thickness was calculated from measurements taken at the first rib, last rib, and last lumbar vertebra. Loin eye area was determined as an average of the left and right sides. The loins were cut perpendicular to the vertebral column between the 10th and 11th rib to expose the longissimus dorsi. Tracings of the perimeter of the loin eye were made, and their area determined by the use of a compensating polar pi an irneter. The carcasses v/ere broken down by standard procedure and v.'eight of v/holesale cuts was determined. In addition, the loin eye muscle was scored for marbling, color, and firmness (Tables 6, 7, and 8). Blade loin roasts and loin chops v/ere wrapped for freezing and were frozen and stored at -15° C. Before cooking, roasts and chops v.'ere thawed overnight at 10" C. Roasts v/ere cooked in covered Pyrex dishes in an oven preheated to 175° C. The same cooking temperature was used for chops as for roasts. Chops were cooked in Pyrex Petri dishes covered with v/atch glasses. Roasts were cooked 60 to SO minutes per kg to an internal temperature of 175° C; chops v/ere cooked for approximately 30 minutes. Aroma and flavor were determined by a trained 6 member panel. Degree of boar odor and flavor were the only palatibility factors considered. Table 9 shov/s the code used for scoring samples. 38 Tissue Sampling and Preparation Loin chops 2.5 cm thick taken between the 10th and 13 rib v/ere wrapped for freezing and frozen and stored at -15' C for subsequent chemical analysis. To prepare the sample chop for analysis, a band saw was used to isolate the longissimus dorsi v/hile the chop was still frozen. All external fat and bone were removed. The remaining frozen longissimus dorsi section was quartered with the band saw, placed in a coded plastic bag, and returned to the freezer for pulverizing. Longissimus dorsi sections were pulverized in the freezer room at -15° C by placing each sample Individually In a commercial duty, rotary- blade blender v/ith a 1 liter stainless steel container, along with 200 g of dry Ice (approximately twice the sample volume). The blender was cooled to -15° C in the freezer prior to use. The cover v^as placed on the blender, held in place firmly by hand, and the blender was switched on to high speed. After approximately 60 seconds the blender was switched off, the pulverized, frozen composite of meat and dry ice v/as placed in a coded plastic bag, and the bag was closed loosely with a rubber band. The pulverized samples were stored in the freezer at -15° C for at least 2k hours prior to \;eighlng out aliquots for analysis. This storage Interval was necessary to allow time for all of the pulverized dry ice to sublime, leaving only the pulverized frozen meat in the sample bag. Sample aliquots of powdered meat were v^eighed while frozen in a cool room (2° - A" C) as quickly as possible to prevent thawing. 39 Feed Sampling and Preparation Feed samples were taken from each mixing batch and pooled at the end of the feeding trial. A sample of this composite v/as retained for chemical analysis. Following drying, the sample of feed was ground in a Wiley mill with a 1 mm screen. The ground sample was stored in a coded glass screw-top bottle for chemical analysis. Feces Sampling and Preparation In the metabolism trials (Experiments 178-E and F) total collection of feces from each pig for each 2^ hours of the 6 day collection period was performed. The feces were put in coded plastic bags, weighed to the nearest 0. 1 g on a single pan balance, frozen, and stored at -15° C for later analysis. Preparation for analysis v/as begun by thav/ing the frozen feces. The entire amount of feces from each pig for each day of the collection period was placed individually in a corrmercial duty rotary-blade blender with a stainless steel container having a A liter capacity. An amount of distilled water equal in weight to the original weight of the feces sample was added, and the blender was switched on to high speed. The resulting slurry was a completely homogeneous mix- ture from which a truly representative sample aliquot could be taken easily. Following drying, each sample was ground in a Wiley mill with a 1 mm screen and stored in a coded glass screw-cap bottle. Urine Sampling and Preparation In the metabolism trials (Experiments 173-E and F) , total collec- tion of urine from each pig for each 2^ hours of the 6 day collection ^0 period was performed. The total volume of the daily urinary output vias measured to the nearest 5 rnl in a 2 liter graduated cylinder. From the total daily urinary output of each pig, an aliquot of approx- imately 250 ml v/as filtered through cheesecloth into a coded poly- ethylene screw cap bottle to which 1.0 ml of concentrated hydrochloric acid was added as a preservative. The pH was tested with pHydrion paper to be sure it v/as in the range of 1,5 to 2.0. If it was not, concentrated hydrochloric acid was further added, drop by drop, until the desired pH v/as obtained. Samples were then frozen and stored at -15" C. Analytical Methods Weighing Samples All samples for analysis v;ere weighed on a single pan analytical balance to h decimal places. Aluminum foil weighing dishes were used for all samples except those on which nitrogen v.-as to be determined; those samples were weighed on small squares of glassine paper and folded quantitatively within the paper for analysis. Moisture Determination Moisture was determined on all feed, feces, and meat samples taken during the course of the investigation. Feed and feces samples were dried prior to grinding as previously described and the moisture was determined at this initial drying. The general procedure for determination of moisture was similar for feed, feces, and meat. Duplicate samples of the material being analyzed v;ere quantitatively weighed into numbered aluminum foil weighing dishes of known weight and placed in a 100° C drying oven. Feed samples were dried for 2h hours, but feces and meat samples required k8 to 72 hours before a complete removal of v;ater was accomplished. The dried samples were cooled to room temperature in desiccators and weighed to determine the loss of moisture. In the case of feces samples it v;as necessary to correct for the water added during homo- genization. Sample size for feed was approximately 50 g. Between 100 and 200 g of feces slurry was used for the moisture determination on the feces samples. Meat sample size was between 5 and 15 g. Dried samples of feed and feces were ground and stored as previously de- ■. scribed. Heat samples remained In their small (6 x 1.5 cm) aluminum foil v;eighing dishes and were stored in desiccators for later analysis. Ether Extract Determination The ether extract determination v/as performed on the same meat samples used in the moisture determination. The small foil pans con- taining the dried meat samples were carefully rolled up to quantita- tively enclose the samples; then the rolled pans with samples v/ere placed in numbered V/hatman cellulose extraction thimbles (25 x 80 mm). The weight of each thimble, pan, and sample v/as quantitatively deter- mined. Samples v/ere then extracted for 2h hours with petroleum ether on a Goldfiscb apparatus. Follov/ing extraction, the samples were dried and the weight of the thimble, pan, and extracted sample was quantitatively determined. The difference v/.is reported as fat. *2 Nitrogen Determination A modified Kjeldahl process (V/.V. Stradtmann, personal conmuni- cat ion) was used for nitrogen determination. Feed, feces, and meat samples for this determination v;ere quantitatively weighed onto small squares of glassine paper (approximately 8 x 10 cm). The papers were then carefully folded to quantitatively enclose the samples, and the papers with samples v;ere put Into coded 100 m! Pyrex semi-micro digestion flasks. Sample size was approximately 0.^ g for feed and feces and 1.0 to 1.5 g for meat samples. Urine samples were pipetted into the digestion flasks. Sample volume for urine was ^.0 or 5.0 ml. After the sample was in the digestion flask, 5 or 6 glass beads were added to prevent bumping during digestion. Concentrated sulfuric acid (5 ml) was used to char the samples for digest ion. The flasks containing samples, beads, and acid were then boiled over a free flame until sulfur trioxide fumes appeared in the necks of the flasks, and acid was refluxing down the necks and sides of the flasks. The flasks were then removed from heat and allov/ed to cool in the air for about 1 minute. Superoxol (30°^ hydrogen peroxide) was added drop by drop to the hot acid digests until the blackish-brown mixture turned clear, indicating complete oxidation of organic matter. The digested sample was then cooled in the air to ambient temperature and quantitatively transferred from the semi-micro digestion flasks to 500 ml macro distillation flasks. Three washes with distilled water were used to accomplish the transfer. The sample was then treated as in the normal Kjeldahl process (A.O.A.C., I960). Mossy zinc and A3 concentrated sodium hydroxide were added and the alkaline mixture was distilled to drive off c-ininionia into receiving flasks containing 50.00 ml of dilute sulfuric acid of known normality. Following dis- tillation, the acid remaining in the receiving flasks was titrated to the metliyl red end point with 0.1000 normal sodium hydroxide. The percent nitrogen in the samples was then calculated, and in the case of feed samples and meat samples it v/as multiplied by a factor of 6.25 to convert to percent protein. A blank and a standard (ammonium sulfate) determination were run with every group of 2k samples. Determination of 17~ketosteroids in Urine A determination of the urinary 17-ketosteroids (Sigma Tentative Technical Bulletin No. 17-KS) was performed on composite samples of urine from each pig in the metabolism trials (Experiments I78-E and F) . In order to compensate for variation in daily urine output vol- ume, samples from each pig for each day of the collection period were pooled in a ratio comparable to the daily urine volume. Duplicate determinations of 17-ketosteroids were run on the composite samples and the results were reported as average excretion of 17-ketosteroids in mg per day. The Zimmerman reaction (Dorfman and Shipley, 1956) v/as used to determine concentration of 17-ketosteroids in urine. Fil- tered urine samples of 5.0 ml were acid hydrolyzed (to free conjugated steroids) in a boiling water bath for 15 minutes, cooled, and trans- ferred to separatory funnels. The hydrolyzed samples were then extracted with approximately 20 ml of ethyl ether and washed with 2.0 normal sodium hydroxide. The washed extracts v^ere filtered into large test tubes, evaporated to dryness, and redissolved in 0.20 ml of absolute methanol. The alcoholic solutions were Incubated at room temperature for 20 minutes following the addition of 0.20 ml of meta-din i t ro-benzene and 0.20 ml of 8.0 normal potassium hydroxide to each sample. Following incubation, 1.0 ml of distilled water and 5.0 ml of methylene chloride were added to each sample and the solu- tions were shaken to mix thoroughly. Approximately 5 minutes after shaking, the top aqueous layer was aspirated off the solutions and 1.50 ml of absolute methanol was added to allow development of the purplish color characteristic of the steroid-dinl trobenzene complex. Solutions v;ere transferred to cuvettes and the percent transmi ttance v/as read in a colorimeter with the blank solution as a reference for 100 percent transmi ttance. Maximum absorbency occurred at a v/avelength of 5'fO my. A standard solution was also carried through the extraction pro- cess v;ith every 8 determinations. The percent transmi ttance values of a series of solutions of known concentration were plotted on semi- logarithmic graph paper to produce a linear standard curve from which the concentration of 1 7-ketosteroids in unknown solutions could be determined directly. The concentration of 1 7-ketosterolds in mg per liter was multiplied by the mean daily urine output in liters to give the value in mg of 1 7"ketosteroids excreted per day. ^5 Statistical Methods All data collected from the experiments v-/ere analyzed statis- tically using the methods of Steel and Torrie (I96O). Analysis of variance vias used to determine significant effects. V/herever significant main effects v^ere not complicated by interaction, pooled means for the main effects are presented in the figures. Any refer- ence to statistical significance regarding main effects refers to the probability level of 5 percent or less. Wherever significant 3 factor interaction occurred, means for the treatments were tested for significant differences by Tukey's uj procedure using the upper 10 percentage points of the studentized range. Wherever a significant 2 factor interaction occurred in the 3 factor experiments (178-A and B) data v/ere summed and averaged across the independent factor. The 2 factor simple effects were then tested for significant difference by Tukey's u procedure using the upper 10 percentage points of the studentized range. Treatment means in the 2 factor experiment (I78-D) were tested in a similar manner where interaction occurred. Since Tukey's procedure is so conservative, Steel and Torrie (1560) suggest that the experiment-wise error rate can be relaxed to 10 percent without danger of committing a large number of Type I errors (declaring observed differences falsely significant). Because of this, the 10 percent level was used to test for significant differ- ences in these experiments where interaction occurred. The standard deviation of a treatment mean (s-) was estimated by i»6 /error mean square / no. of observations in mean for calculating u. The value of 0) = q^ • s~, where a = 0.10, p = number of means being compared, and n2 = error degrees of freedom. The q values were obtained from tables of the upper percentage points of the studentized range (Beyer, 1966). Experiment 178-A Experimental A group of 72 carefully selected crossbred pigs was placed on experiment at an initial average weight of ^5 kg. This first trial was begun on February 16, 1S67. Pigs were group fed in concrete con- finement from a self feeder to an average weight of 95.3 kg, at which time the entire group was slaughtered for carcass study. The termination of the feeding trial was on April 22, 1967, 66 days after the starting date. The design of the experiment was a 2 x 2 x 2 factorial design (Table 10) which involved sex (barrow and gilt), protein level (16 and ]2% protein), and hormone supplementation (basal and DES + MT , each at 2.2 mg/kg of feed). Compositions of the rations used are shown in Table I. Results The summaries, analysis of variance plans, and observed mean squares for Experiment I78-A are presented in Tables 11 through 16 and Figures 1 through 12. Table 13 presents an overall summary of all the responses measured in Experim,ent I78-A. Significant mean ^7 squares are presented in Tables l'^ through 16. Figures illustrate all significant interactions and main effects. Table 11 presents a sunnmary of the feedlot performance of the k treatment groups. Table 12 shows the combined protein and hormone treatment means and the appropriate standard deviations of treatment mean?. The t test did not reveal any significant diffcrcncco in feed- lot performance due to hormone or sex. Treatment means of total gain from initial to market are shov/n in Table 13. There were no significant differences in total gain between any treatments. Carcass responses are shown' in Table 13- There v/as a signi- ficant protein x hormone x sex interaction which affected dressing percentage. This interaction is illustrated in Figure 1. Gilts showed an increased dressing percentage on the basal ration as protein was increased, and a decreased dressing percentage was noted when protein v/as increased on the hormone supplemented ration. The reverse effect v/as seen in barrov/s. Hormone increased dressing percentage with increasing protein. Increasing protein on the basal ration did not affect barrov; dressing percentage. The effect of hormone supple- mentation in reducing dressing percentage v/as significant only at the 16 percent protein level in gilts and at the 12 percent protein level In barrov/s. Due to this interaction, no inferences can be made about the main effects on dressing percent. There were two significant interactions which influenced percent lean primal cut yield. The 2 factor hormone x sex interaction v/as disregarded since there v/as also a significant 3 factor interaction. The 3 factor protein x hormone x sex interaction illustrated in ^8 Figure 2 shows that gilts responded nearly the same on the basal and hormone rations to increased protein. There was an increased lean pri- mal cut yield in gilts fed either diet (basal or DES + MT) v;hen protein was increased. Barrows showed increased lean primal cut yield in response to hormone supplementation at both protein levels. Barrows fed the 16 percent diet had a higher lean cut yield Llian uiose fed the 12 percent protein regardless of hormone level. None of these differences were significant (Table 13)- Percent ham v-zas not affected by any factor except sex (Figure 3). Gilts had significantly larger hams than barrows. Percent loin was influenced by a significant 2 factor interaction. This hormone x sex interaction is shown in Figure h. Percent loin was slightly decreased in gilts by hormone, but barrows showed a signifi- cant increase in yield of loin in response to DES + MT. In addition, gilts fed the basal diet yielded significantly higher percentages of loin than basal barrows. Percent yield of picnic shoulder was influenced by both hormone and protein. There was a significant increase in percent picnic shoulder in response to increased protein (Figure 5) and to hormone supplementation (Figure 6). Percent Boston butt was significantly increased by hormone supplementat ion . (Figure 7). In addition, there was a significant protein x sex interaction influence on yield of Boston butt. Barrov^/s showed a slight decrease in yield of Boston butt with increased pro- tein, but gilts showed a moderate increase. Although this inter- action was significant, none of the differences betv/een means were significant (Figure 8). A9 Backfat thickness was decreased significantly by both increasing protein and DES + MT (Figures 9 and 10). No interactions were observed to influence backfat thickness in this trial. Loin eye area v/as not significantly affected by any of the treat- ments in this experiment. No significant differences in carcass length due to treatrrient were observed. Loin eye marbling score was significantly reduced by increased protel n (Figure 11). No differences due to treatment v/ere observed in loin eye color score or firmness score. Loin roast aroma and flavor scores for boar odor incidence v-^ere significantly increased by DES + MT in this trial. A graphic presen- tation of this difference is shov/n in Figure 12. Experiment 178-B Experimental Experiment 178-B was the second trial performed in the series, and was designed in 2 parts. The first phase consisted of a completely random design (Table 1?) with sex of the pigs (barrow or gilt) as the treatment factor. A careful ly chosen group of 60 young crossbred pigs with each sex represented equally was placed on experiment on May 15, 1967. The average initial v/eight was 9.8 kg. The pigs were 50 segregated by sex and group fed on a 16 percent protein ration in confinement on concrete to an average v;elght of 5^.3 kg. The first phase ended on July 25, 196'/. The feedlot performance data collected were analyzed to determine if there was any performance difference In early life due to sex. The second nh;^sf= of the e^fnprimpnf; w^s a ? X ' X 2 factorial design similar to Experiment I78-A. This trial was designed to further investigate the effects of sex, protein level and hormone supplemen- tation on growing-finishing pigs. The design of the experiment Is shown In Table 18. in this experiment it was decided to use a lov.'er level of protein (l^^) than the 16 percent ration used in the first trial, to see if a response to protein still occurred, and to see if response to horinone remained the same at the lov/er level of protein. Pigs in this trial were individually fed from self feeders in concrete confinement pens. Compositions of the diets used are shcv.'n in Table i. The 43 pigs used in this second phase were selected from tne 60 pigs used in the first phase on a sex, weight, and llttermate basis. Starting date for the factorial trial was July 25, 196?. All pigs were slaughtered (for carcass study) on an individual basis as ter- minal weight reached approximately 100 kg. Results The summaries of treatment means and analysis of variance plans for Experiment I78-B are shown In Tables I9 through 2h and Figures 15 through 22. . 51 A suraTiary of the feerflot performance during the growing phase is shown in Table 19. Mo siynificant differences were observed in per- formance during early life between barrows and gilts fed a similar 16 percent protein ration (Table 20). Average daily gain was significantly greater for barrows than for qilts duTrnc the f:.-.:''---- ~i~^~- fr;^..^. y -,\ -r, a -- --. ...i^ L,.v. ^,,.,.y pnaoo M lyuTc ij>;. Tlieie Wdi d Signi- ficant interaction of sex with DES + MT which influenced feed intake. Barrows fed DES + MT ate significantly less feed during the finishing phase than did barrows consuming the basal ration. Hormone supplemen- tation did not affect feed intake in gilts (Figure Ui) . In addition, Figure ]k shows that barrows fed the basal ration ate significantly more feed than gilts fed either the basal or the hormone diet. Feed efficiency was significantly improved by DES + MT in this trial (Figure 15). None of the main effects had a significant influence on dressing percentage In this experiment, but there was a significant protein x sex interaction effect (Figure 16). Increased protein resulted in Increased dressing percentage in barrows; this response was signifi- cant in gilts. There was a favorable effect of DES + MT on percent yield of lean primal cuts. There was a significant interaction of sex x hormone which is shown in Figure 17. This interaction manifested itself in a differential response to hormone supplementation by sex. Gilts showed only a slight increase in percent lean primal cuts, while barrows showed a significant Increase. There were no significant differences observed In percent ham in this trial. 52 There was a significant interaction of hormone x sex affecting percent loin. Loin yield in gilts v\fas not materially affected by DES + MT, but barrov^s showed a significant increase in this cut due to hormone supplementation (Figure 18). Picnic shoulder and Boston butt percentage yield were unaffected in this t r i ■? 1 bv an" treatment. Backfat thickness was significantly reduced in barrows by DES + MT in this experiment. There were 2 significant interactions influencing backfat thickness. The effects of both protein x hormone and hormone x sex interactions are presented in Figure 19. The protein x hormone interaction shows that average backfat thickness was not materially affected by DES + MT on the high protein diet, but was significantly reduced on the low protein diet. The hormone x sex interaction shows that backfat thickness was not reduced in gilts fed DES + MT, but was decreased to a significant extent in barrov/s. Hormone x sex interaction significantly influenced loin eye area In this experiment, but none of the treatment means differed signifi- cantly. Carcass length was significantly increased by DES + MT in gilts fed 12 percent protein in this trial. There was a significant 3 factor interaction which influenced carcass length (Figure 20). Gilts fed the basal ration showed an increase in carcass length as protein was increased from 12 to 1^ percent, but gilts fed the ration containing DES + MT showed decreased length with increased protein. The reverse effect was true for barrows. DES + MT increased length of barrows with increasing protein; barrows fed the basal ration showed a decreased 53 length as protein v/as increased. None of these effects were signi- ficant, with the exception of the difference between gilts on the basal and hormone rations at the 12 percent protein level. Loin eye marbl ing score was not affected by any treatment in th is trial . Loin eye color score w^s not- s inn I f icant )y different between any of the treatment groups in this trial. Loin eye firmness score was significantly affected by sex. Gilts had significantly firmer muscle (lOth rib _1_. dorsi ) than barrows (Figure 21 ) . Loin roast aroma and flavor scores for incidence of boar odor and flavor v/ere significantly increased by DES + MT in this experi- ment (Figure 22) . Experiment 178-C Experimental The third trial in the series was designated as Experiment I78-C. This trial was designed to examine the effects of DES + MT alone, without protein or sex considerations. The experiment was a completely random design (Table 25) utilizing 2h barrov/s individually fed in concrete confinement from self feeders. The ration used (Table l) was a 1^ percent protein corn-soybean meal diet fed with and without 2.2 mg of DES + MT per kg of feed. Pigs for this experiment were randomly assigned to treatment from a uniform group. The trial com- menced on January 23, 1969. Pigs averaged kS kg initially and were slaughtered on an individual basis for carcass study as weight reached 100 kg. There were 2 pigs in the trial, one assigned to each treat- ment, with identical ear notch numbers; the identity of these two animals v/as lost at slaughter. Therefore, the carcass data are all based on the remaining 11 pigs in each treatment group. Longissimus dors! samples from the 10th tc 13tS". rib area \:crc analyzed for moisture, fat, and protein content in this trial. Results The treatment means for Experiment 178-C are summarized in Table 26. Analysis of variance tables for this experiment are given in Tables 27 through 31 • Out of 22 responses measured in this trial, only 3 showed any significant differences. Feedlot performance did not differ significantly betv^een treat- ments, but there was a trend toward decreased feed intake and improved efficiency due to DES + HT. None of the carcass objective measurements differed significantly in this experiment, although there was a trend toward increased lean- ness due to DES + MT. This was evidenced by slight increases in carcass length and yield of lean cuts, and slight decreases in dressing percent, backfat thickness and loin eye marbling score. Of all the carcass leanness parameters, backfat thickness was most affected by hormone supplementation, but even so, the difference was not signifi- cant. In this trial the only carcass subjective measurement which was significantly affected by DES + MT was pork chop aroma score. There 55 was a significantly higher incidence of boar odor in chops from pigs treated with DES + HT. None of the other carcass subjective measure- ments, including chop flavor score, roast aroma score, and roast flavor score, were significantly different. Analysis of longissimus dorsi samples revealed a significantly luwer perueiiLdge of dry niacLer vhigner Z moisture) in pigs fed DES + MT. The percent protein in longissimus dorsi was significantly greater for pigs fed DES + MT. Protein was expressed on a dry matter basis. There was no significant difference in percent fat in longissimus dorsi , although there was a trend toward decreased fat due to DES + MT. Experiment 178-D Experimental Experiment 178-D was the last in a series of ^ feeding trials. In this trial, the design was a 2 x 2 factorial (Table 32) involving sex and hormone supplementation. The protein level was fixed at \k percent of the diet (Table 1). The crossbred pigs used in this experiment were selected from outcome groups based on sex, v;eight, and litterm-ate, and were randomly assigned to treatments. The pigs were fed in individual concrete confinement pens from self-feeders. The average initial v/eight was 5'<.5 kg. Pigs were slaughtered on an Individual basis for carcass study as they reached 100 kg. The trial commenced on May 19, 1969. On this trial, one barrow died midway 56 through the experiment. Death was attributed to generalized edema due to heat prostration. One pig carcass was condemned for a condition of granuloma in the muscle, apparently unrelated to treatment. Be- cause the orthogonality of the factorial design was destroyed by loss of these data, computer analysis using a complete and a reduced model y/^c; ri'='c^ss9rv in order to partition the surris of SGUorss. Therefore, only abbreviated analysis of variance tables are shov/n, and sums of squares generated from these tables are not additive. Results The summary of treatment means is shown in Table 33, and abbre- viated analysis of variance tables are presented in Tables 3'* through 37 and Figures 23 through 38 illustrate significant effects. The interaction of hormone and sex influenced daily gain signi- ficantly. This interaction is graphed In Figure 23, which shows that daily gain in gilts was not materially affected by DtS + MI, but was significantly reduced in barrows by the hormone. Barrows fed the basal diet gained significantly more than did gilts fed the basal diet. Average daily feed intake was significantly greater in barrows than in gilts (Figure 2^). Hormone supplementation also influenced daily feed intake significantly. Pigs fed DES + MT consumed signifi- cantly less feed than those fed the basal diet (Figure 25). Feed conversion efficiency was favorably affected by DES + MT. Pigs consuming the hormone supplemented feed had a significantly lower feed conversion ratio than pigs fed the basal diet. This differ- ence Is shown in Figure 26. 57 Dressing percentage was not affected by any treatment in this experiment. Hormone supplementation markedly increased the percent yield of lean primal cuts in this experiment (Figure 27). There were no significant main effects seen in percent ham yield, but the hormone x sex interact ion \izz significant. This interaction is illustrated in Figure 28. The graph shows that DES + MT decreased yield of ham slightly in gilts, but increased it significantly in barrows. Gilts fed the basal ration had significantly larger hams than barrows fed the basal ration. Percent yield of loin was not significantly affected by any treatment. Percent yield of picnic shoulder was increased by DES + MT. This effect v;as significant (Figure 29). There was also a positive significant response to DES + MT manifested in percent yield of Boston butt (Figure 30). Backfat thickness was significantly reduced by supplementation with DES + MT (Figure 31) • Loin eye area was not affected by any treatment in this trial, nor was carcass length. Liver weight was also measured In this trial, but no significant differences due to any treatment were observed. Loin eye marbling score, loin eye color score, and loin eye firmness score were all unaffected by any treatment. Loin tenderness score was significantly different between sexes (Figure 32). The meat from barrows required less shear force to part the fibers than did that from gilts. 58 In this trial, the boar odor and flavor incidence scores for pork chop aroma and flavor and loin roast aroma and flavor were sig- nificantly increased by DES + MT (Figures 33 and 3^) . Moisture, fat, and protein v/ere determined on longisslmus dorsi samples taken from the 10th to 13th rib area. The percent dry matter J rt ^1^2 meet \'/C S IT^*" ^i'^n'fi' "^*']»' ^tf-r*-**-!^^-*^ kr»^^...-»rtr^ f'»-(a-\t-'r%^f-»*-cr Percent protein in long iss imus dors i (expressed on a dry matter basis) was significantly lower in barrows than in gilts, and v/as significantly decreased by hormone supplementation (Figures 35 and 36) Percent fat in longiss imus dors i (expressed on a dry matter basis) was significantly affected by sex and DES + MT. In this trial, gilts showed significantly less fat in the lean tissue than barrows (Figure 37). Supplementation with DES + MT significantly increased the percent fat in longissimus dorsi over that found in pigs fed the basal ration (Figure 38). This trial concluded the series of feedlot performance and carcass study experiments. Table kk presents a summary of all the significant performance and carcass responses observed in the h trials, Experiments 178-E and F Experimental Experiments 178-E and F were the last two experiments performed in the 178 series. Both of these trials were metabolism studies. Barrows were housed in metabolism crates constructed so as to permit total collection of all excreta separately. The crates were equipped a 59 with automatic water fountains, and with fans for cooling. The floors were of expanded steel mesh. Barrows were ful 1 -hand-fed twice daily and a record of daily feed intake was made. Barrows were weighed, placed in the crates, and fed the experimental diets for a period of acclimatization to the regime. The pretrial period v/as 9 days in the first r^stobolism trial end 11 days in the second one. Co! lection of total feces and urine excreted was made as previously described for a period of 6 days in both trials. Barro-ws were weighed again at the termination of the feeding period. The design of the experiments is shown in Table 38. In the first metabolism trial (conducted from Hay 29 to June 12, I969), crossbred barrows averaging 58 kg initially were used; terminal verage weight was 65.7 kg. In the second metabolism trial (conducted from July 28 to August ]h, I969), similar barrows were used. Average initial weight was 57-1 kg, and average terminal weight was 67.8 kg. Each trial consisted of 8 barrov/s; the blocks used in the design were littermate pairs, and four barrows were assigned to each treat- ment. The basal {]kZ protein) diet was fed with and without 2.2 mg of DES + MT per kg of feed, as shown in Table 1. Criteria examined in both trials were daily feed intake, total gain, daily nitrogen retention (g N/kg feed consumed), apparent di- gestibility of dry matter and nitrogen, and excretion of 17-keto- steroids in urine. Results The treatment means for both trials are shown in Table 39, and analysis of variance plans are presented in Tables kO and ^1 for 60 for Experiment 178-E and Tables k2 and k'i for Experiment I78-F. No significant difference due to DES + MT was observed in daily feed intake, although a slight decrease in feed intake in the first metabolism trial and a more marked decrease in the second occurred In pigs fed the hormone supplement. Total gain was very slIyhLiy uecredbed In pigs fed DE3 -i- HT in Experiment I78-E, but was moderately increased in hormone supple- mented pigs in Experiment I78-F. Neither difference was significant, however. Daily nitrogen retention, expressed as g of nitrogen retained per kg of feed consumed, did not differ significantly due to treat- ment in either trial. Pigs fed DES + MT shewed a moderate decrease in nitrogen retention in the first metabolism trial, but showed only a slight decrease In the second trial; neither difference v^as great enough to be significant. Apparent digestibility of dry matter and nitrogen was similar for both treatment groups in both trials. Digestibility did not appear to vary betv/een trials, either. In the first metabolism trial, excretion of 1 7-ketosteroids In urine was significantly different due to treatment. Pigs fed DES + MT had a higher daily excretion of 1 7-ketosteroids in urine than pigs fed the basal ration. In the second trial opposite results were ob- served. Pigs fed the hormone supplement in this experiment showed a lower daily excretion of 1 7-ketosteroids in urine than did pigs fed the basal diet, but this difference was not significant. GENERAL DISCUSSION The Effects of Hormone, Protein, and Sc-x on the Ft^prllo' pprfrir.vnr.rp nf (^rnu i nn -p i n i s h i nn $wino Several recent studies have been reported which indicate that DES + MT affects the performance of swine in the feedlot. Wal lace et^ £l_. (I967) reported a significant decrease in both average daily gain and average daily feed intake due to feeding DES + MT at 2.2 mg each per kg of diet. Baker et al. (I967) reported that DES + MT decreased average daily gain in barrcv/s, but not in gilts. They observed also that feed efficiency response to DES + MT was obtained only at higher levels of protein. Doornenbal and Frankenham (I969) reported a non-significant increase in average daily gain for gilts and barrows fed a practical high protein ration containing 2.2 mg each of DES + MT per kg of feed, but they reported that feed efficiency was not altered by treatment. Average Da i ly Gain In this series of experiments, rate of gain was affected signif- icantly by hormone in only 1 out of k trials (Table kh) ' Hormone treatment decreased rate of gain only in barrov;s in this particular case, since there v/as a significant interaction of hormone x sex. 6f 62 Sex affected rate of gain in two trials (Table ^k) . Barrows gained significantly faster than gilts. No effect on rate of gain due to protein level was observed in any trial. Barrows responded significantly more to DES + MT than gilts. This difference was manifested in a marked decrease in rate of gain ■for hormone s '-"^piemen ted barrows b'jt essentially nc change v.'cc observed in gilts fed the hormone. This interaction of DES + MT with other factors (especially sex and protein level) may be one reason that some of the responses to DES + MT in some trials have been so variable. This observation on gain response to DES + MT is in general agreement with other work reported in papers mentioned in the litera- ture review. Gain response to this combination of hormones has been erratic at best, and it may be that the response varies with experi- mental conditions. Average Daily Feed Intake Feed intake is one of the most variable parameters in animal research. Daily feed consumption can be affected by a variety of factors, including hormone supplementation, sex, and protein level. In this experiment there was a significant reduction in feed intake attributed to DES + MT in the second and fourth feeding trials (Table Uk) \ . In the other trials there was a marked trend toward reduced feed intake due to hormone, but the effect was not significant. There was a significant hormone x sex interaction in Experiment I78-B. This pattern has been noted by other v;orkers (Wallace et^ fj.' ' ^5^7; Beacom, I963) who reported that feed intake in gilts was unaffected by 63 hornrane supplementation, but was markedly decreased in barrows when DES + MT was added to the ration. in this experiment sex also in- fluenced daily feed intake significantly in the last feeding trial (Table kh) . Barrows consumed significantly more than gilts in this trial . The observed trend tc-.-ard decreased feed intake was rather con- sistent in this study, and has also been reported by numerous other workers. Either DES or MT fed alone is capable of eliciting the re- sponse (Dinusson e^ aj_. , 1951). The feed intake reduction is most probably one of the factors contributing to reduced rate of growth and increased feed efficiency reported in many of the trials involving hormone supplementation. Feed Conversion Efficiency The feed conversion efficiency ratio (feed/gain) was significantly Improved by DES + MT in the same 2 trials which showed a significant decrease in feed intake caused by the hormone. Neither sex nor pro- tein significantly influenced feed efficiency in any trial conducted in this experiment. It is probable that the decreased feed intake due to hormone was responsible for this increased efficiency observed in the same experiments. Dinusson e^ aj_. (1951) and Heitman and Clegg (1957) reported improved efficiency due to supplementation with DES. Wallace e£aj_. (I967) reported that increased feed conversion efficiency due to DES + MT was manifested most at higher protein levels. This Is in agreement with the work of Baker et^ a]^. (196?), who re- ported similar findings. Opposite results were observed in this study. There v/ere 2 trials in which protein level varied (Experiments I78-A and B) . N'o signifi- cant differences in feed efficiency were observed in Experiment I78-A, but in Experiment I7S-B there v;as a more marked improvement in efficiency due to DES + MT in pigs fed the low protein diet than in tho5 Chemotherapeut ic premix^id Protein levels, % 12 li* 16 89.05 8^.05 79.05 8.00 13.00 18.00 1.80 1.80 1.80 0.50 0.50 0.50 0.50 0.50 0.50 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Totals 100.00 100.00 100.00 3 The composition is shov;n in Table 3. ^ The vitamin fortification is shown in Table A. c Basal diets contained tylosin phosphate, 11.0 mg/kg. ^ Hormone diets contained 2.2 mg/kg each of diethylst i Ibest rol and methyl testosterone and 11.0 mg/kg of tylosin phosphate. Table 2. Experiment 178. Calculated analysis of diets Calculated analysis Protein levels, % 12 ]h 16 Protein, % Energy, mat. cal./kg Calcium, % Phosphorus, % Vitamin A, I .U./kg Vitamin D3, I. U./kg Riboflavin, mg/kg Niacin, mg/kg Choi ine , mg/kg Vitamin B12, pg/kg Pantothenic acid, mg/kg 11.93 13.99 16. Oi* 3208 3166 3123 0.80 0.80 0.80 0.62 0.62 0.62 5700 5723 5557 kii] kk] Aitl 12.5 12.5 12.5 215.'* 215. 'j 215.^ 800.0 800.0 800.0 11.0 11.0 11.0 20.0 20.0 20.0 82 Table 3. Experiment 178. Composition and contribution of trace mineral premix 35C-73 Element^ in premix Level in feed when added at 0.05% iTig/kg Manganese Zinc Iron Copper Cobalt Iodine 10.0 10. 0 10.0 1.0 0.1 0.3 50.0 50.0 50.0 5.0 0.5 1.5 Supplied as manganese sulfate, ferrous sulfate, ferrous carbonate, iron oxide, copper oxide, cobalt carbonate, potassium iodide, and zinc sulfate. Table k. Experiment 178. Contribution of vitamin prenii: Vitamin Contribution per kg diet Riboflavin Niacin Pantothenic acid Choi ine chloride Vitamin B Vitamin A Vitamin D3 12 6.6 mg 22.1 mg 13.2 mg 88.2 mg 11.0 yg 2756 I.U. ij'il I.U. Table 5. Experiment 178. Dry matter and protein analysis, % of diets Analysis Protein levels, % 12 1^ 16 Dry matter, % Crude protein, % (d.m. basis) 85. 8i* 86.93 85.53 12.71 1^.58 16.^'* 83 Table 6. Experimant 178. Code for marbling score of longissimus dors! at lOth rib Amount of marbling Devoid Practical ly devoid Traces SI ight Smal I Modest Moderate SI ight ly abundant Moderately abundant Abundant Very abundant Extremely abundant Code 0 1 2 3 4 5 6 7 8 9 10 11 12 13 \k 15 16 17 18 19 20 21 22 23 2k 25 26 27 28 29 30 31 32 33 Table 7, Experiment 178. Code for color of longissimus dorsi at 10th rib Color of lean Code Very dark Dark Greyish pink (ideal) Lightly light in color Chicken meated - very light 8A Table 8. Experiment 178. Code for firrnness of longissimus dorsi at 10th rib Firmness of lean Code Hard Medium hard Medium soft Soft Oily Table 9. Experiment 178. Code for boar odor and flavor score Degree of boar odor or flavor Code None SI ight Moderate Strong 85 Table 10. Experiment 178-A. Experimental design and distribution of animals Lot Treatment factor 1 2 DES + ^^r Protein level , % Number of pigs^ ~ + - + 16 16 12 12 18 18 18 18 ^ Each lot consisted of S barrows and 9 gilts. Table 11. Experiment 178-A. Summary of feedlot performance Treatments 16^ C.P. 16% C.P. 12% C.P. 12% C.P. Criteria Basal DES + MT Basal DES + MT Average dai ly feed, kg 2. .62 2, .53 2, .86 2, .7^* Average dai ly gu 1 n , kg (66 days) 0. .75 0. .75 0. .81 0, .7b Feed/gain 3. .50 3. .36 3 .5h 3. ,ih M - 1 f^ — 0) \x o o t |-u £ CO .> 1_ r-i ; «- s: o R <*- u CL (U 3 (U O 5 u 4-' cr. 0) J3 O u tn 0) - m tt) e u- 87 r«-» O -3- IS\ 0~\ — 00 * r^ -K — t> — I! o c\i oco H II OCL 3 O- h- *P + O ul i/i »0 1/1 (/I U 4) (U (1) &^ IT vo rr. — XI O V O V •iJ E nj o x: — c 10 fo E _ - E 1/1 I- ifl I- O o o 00 D5 O in O I/) i/i 10 (/) — U C DO ^ ...,.>, « _ ^.^ O E £ ^ — 4)— j:— CXJ3 o< c 1-— I. o fa fQl- (DLUOTJO— »-~ C5 0e^5.j'£<>>^e-?i3-j— i2:ou.'^ r>! LTv o O CN O vn 01 O r^ csi LA r^ r«^ o — — OA -3- -3- — — O O t^-\-3- f«^ vJD OO -?• LA O -T -T rsi vO CNJ O CO CO CO o — cr\ o ' cr> cNi -3- \£> r^ Lr\ f ■% — ca — *J CO) O 1- X X X X X >- o « CU 3; 00 Q. Q- 3: Q. 1_ — i_ -u uj in in (/) 0} u LA O O O CJ It II Q. o. to d 89 o - Ul d) > »— c fO .— c o < in ^. "j 4-J o cr u c: Q o O i — ID d) M- c ^ ^ O o TO • — CQ JJ o «- — i) c -o o — ~ 3 D- O d-? in O E O in T3 0) 0) (U o 1. l_ 4) vD 0-\ — r»» -cr 0"» oo CM f»-\ r~. 0\ vD — vD OOOfsJOO— vD — oDcsi-3-r^ — csioo r^ CO — cr>o-3-v£icNi — irvf^crvr^cN. — o LA -TO-3"OCO-3-f»-> — o"» vTi -a- csj J- o o\ CO CN cc c~> o p^ ro -a- — -3- cNj o^ — CM rA -3- ro C~\ CO O — -3- CM -3- CM CM r^ o — CM O O O O O -=■ -3- -T — r-^cMcMr^cnco ^r CM-3-0— OOCMO o — o o o o o CM CNj o o \J\\D ir\ LA CPv 1-n o -3- r-- o -3- o o o vO CM O CM O vO O CM CM O O O O O 4-J CO >". X X X X (/) in (/) Ul 0) 0) o o a u a. o- 4-> .JJ en en Q- :n oo o_ ci. d: G. 90 o w- o «-> «) \fi >- «5J 0) o en X- c O »*- u ^ U3 J3 L. (W TO F e O < CO «> 4) 01 >- i/i r r i- v. o -— ^J u- o e o 0) o 4) (U 1. 1- o o o o o o o ' — f^j CO — — O O r>-> O O O ^ O o o o o o o o o o c> o o o o o o o o o o o CM vO -T tA O LA LA csi LA — CM O LA CNl tN O O — ■ O O — O O O O O O O c 0) X •— c 0) o X CO CO x E o i_ X X X X X I- 0 C) a. a: (J~) a. o. 3: O- in I/) 0) (1) o o LA O o O o II II a. o. 4-> c O 4-1 c m o H- 4- c c C7) s\ Table 17. Experiment I78-B. Experimental design and distribution of animals during the growing phase Sex Number of pigs Lot Gilts 30 1 Barrows 30 2 Table 18. Experiment I78-B. Experimental design and distribution of animals during the finishing phase Lot Treatment factors 1 2 3 ^t 5 6 7 Sex GGGGBBBB Protein level, % 12 12 1^ ]^ 12 12 1^ ]k DES + MT +- + - + - + - Number of pigs 66666666 -92 Table 19. Experinient I78-B. Summary of feedlot performance during the growing phase Criteria Average daily gain, kg Average daily feed, kg Feed/gain Gilts 2.72 Sex Barrov;s 0.67 l.S^i 2.75 Table. 20. Experiment I78-B. Analysis of variance of average daily gain during the grov/ing phase Source of variation Degrees of freedom Mean square Sex Error Total 1 58 59 ,0086 ,0028 ,0029 93 »D (TJ O •4-J •— U >4- o ■_ u- CT <4- a> 0) Q- — ^r~r~~co COCOv£)\£) r^ o~\ r^"co — — cv~»cmov£>ooo {/) n B — o *-> <*- C3U.O O — JC— Q.J3 O Q Q ^ 1- — CNj o r-- — 0"^ CTv-a- CO r»-\ r--. — 00 I — r^^ -S Ci CM— OLio- — 3-r^ — V cn (0 t. a> > 10 r^— Ot-^OvJDO^ -3" CM ro o~i CO r»~> CM ir> — vjDCTi — CO — OO O r>ar^o — ooo — ooooooo o o .j^e M O) •«. c - u> ^— (/) TO -i . — — CO — CM O ^ O OOOOOOO r-~ — (N vo CO ' — — "— CM o — o o E o L- X X X X X k- o v a. a: t/1 a. Q. 3: 0- o o o o CD cn to to 35 c u o. *^ » c •— ro o 0) ^-- »- ra dv 0) ' >- o 4-1 *-• in A-> O 3 CD XI o O E O O O OJ 4-. CO r-~ cr> o CO vo r^ oD CO cr> o r-j CO cr\ .^ csl r^ O i-r\ vX) M3 •tt ^ ■<: O -\ — cr\ cvi o r^ cr> o^ r^ CM r^ O v£) CvJ — CO ^ o o cr> — -3- ra o — o o o — o CO csl CM Cr> r^ CTi CO — U^ O v£) LA — — O r^ vO — O u-\ -3- O CTv -3- c^ O — LA o o o o o o o CM CM r~~ CM -3- -3- O LA LA M3 O O O lA CO CO CM O vD rA LA CM LA rAOOCAOOCA O ^.3--3-vOCMO — O t^r^CMLACTvCMO CM — CAOO' O-"— SO CMCMCslCMCMCMCTl CM OLALALALAOsD f-^ O CA CA rA CM sD ' — CO CMCNlCM-crOCr»0 — — CM CO CO o — — — o^o — ^ — 1/1 in V 0) O O LA O o O o tl II O- a. O 1- X X X >; X L. o CJ a. X I.) c u^ •— w~- m J3 F U o OJ TO O c — in 4- 0) o o 01 Wl u ,— •— m 4- in >- u 4J ^- O - o c o .— o o >- c (U — o e: o 4) t) o o o o o o o — O »— vO tv^ CN ■ — O r^ r>-^ o O f^\ O O — O O O O O vO o o — 00^-^cs^cJr■-^ — en CNI — — (NOOO — — O ri^ O O O O O u-\ a^ o CD CO -3- o^ r^ o o o o r^ o CO CSJ CM CNI CN CO CvJ — o La u-\ o o o O O CM o o o o O -ij- -3- f*^ fA o ro C c^ (v^ f'-\ r--^ o ro O CO ra roco O CO O O ra fv^ o O O O O O O O O O a-» CTv (v~, (v-» CM ro CO vO •-- r^ r>^ O O O cs' CA vD CO — \0 -5- CO — — JNJ c\4 „ „ ur\ o •" CO ur\ -^ r-~ (-■-, 1/1 U1 in (/) (U 0) O I- X X X X t- O 0) a. 3; lyi Q_ a. 31 LPi O O o O II II Q- Q. c c en en 1/5 C/1 97 Tabic 25. Experiment I78-C. Experimental design Lot Number of barrows^ Treatment 1 12 ]kZ C.P. basal 2 12 ]k% C.P. + DES + MT ^ Each lot contained one pig with identical ear notches. The identity of both these pigs was lost at slaughter; therefore, carcass data are based on the remaining 11 pigs in each lor. Table 26. Experiment 178-C. Summary of mean responses to treatments Treatments ]kZ protein ]kZ protein Response basal DES+HT Average daily gain, kg O.8O O.8O Average daily feed, kg 2.92 2.76 Feed/gain 3.67 3.50 Dressing % 72.97 71.88 % lean primal cuts 52.2^ 52.39 % ham 19.75 20.15 % loin 16.52 16.^7 % picnic shoulder 9.2A 9,21 % Boston butt 6.67 6.55 Average backfat, cm 3.18 3.07 Loin eye area, cm^ 31.28 29.86 Carcass length, cm 77.14 77.57 Loin eye marbling score 12. 6^^ 10.09 Loin eye color score 3.09 3.18 Loin eye firmness score 2.18 2.^45 Pork chop aroma score 1.0^ 1.07- Pork chop flavor score 1.0ft 1.03 Loin roast aroma score 1.03 I.08 Loin roast flavor score 1.00 1.02 % dry matter in J_. do£s i 27.75 26.21- % protein in 1. dorsi fd.m. basis) 7^.77 78.82- % fat in 1. dorsi (d.m. basis) 23.21 21.57 * Significant (P = 0.05 or less). ** Significant (P = 0.01 or less). 98 CO r^ o vD -:J- O r-- iri vo — o o — CO LA CO CO r~^ f>^ LTV LA — o o O E o i-. L. o E* I. ■o nj ^— > a o u- JZ o 1/1 u »_ — O — r~- cr> c: -u -T CN CM o ^~ O -;r -^ — 3 o -a- -T D. o CA O^ O^ — vT) O • — r^-\ cr\ O CM — LA r~^ CO o CO CO -cr CTi rA LA CA v"> — r-- cA rA a\ LA LA CTi CO LA Cvl r^ -^ -5- -3- LA PA -T U1 -D 0) - c vTD r-~ CNl i) • ~ ro -3- r^ ^— vD 01 a~\ c XI • ■ — L. LA-3- LPv o _J E C^ — ■~ 1/1 s: t^ ^ ^ <0 4-J CTiCO . — 0 Oi -3" ro r~- L- c O^ r^ CNl TO (U • • •— 0 CSi CM r>^ vI3 -3- vD Csl -3- -c- o^ o -3- f»~v O Csl CM rsi r~. CO r-^ O CM CM — LA o^ CTv CM mD CO -- — o -3- -3- 0 E 0 in "O dJ (U — 0 — q; 0 CM CM 0 m u V) ak 0) tf> 1. «) 0 a> u c V) E L. n> m^- E M- 0 i- 0) (D >. 0) 4-> in c ro ■^ 0 0 u ^— c 0) 0 L. 0 0 » VI 0; u u 0 0 0 in 0 u u 0 0 > >■ ro V ^— «*- c •^ D. 0 0 »— s: ro 0 Q > 0 ^— (/) 14- 0 ro 4-1 E in in 0 fo •— u 0 m ro 1- >- ^— a c ro 0 • — c JZ 0 ro ro ^ o-\ t^ 0 E \D CO C-\ L. 0 ^ C LA - in ^- CM CM 0) 0) CTiCO r- c 0 — CM c E -3- CM CM — 1- • • • 0 — 0 0 0 LA r^ ro -3- CM CM O in E tu 0 — 0 ^ v -0 CM CM »- o UJ t— 100 Table 31- Experiment I78-C. Analysis of variance of % dry matter, % protein, and % fat in 1. dorsi Mean squares Source of variat ion Degrees of freedom L. dorsi dry matter L. dorsi protein L. dorsi fat Treatment 1 12.9977" 90.1733" I'^.SIS? Error 20 2.1170 20.6030 22.0',')^ Total 21 2.6352 23.9158 21.676*4 Significant (P = 0.05 or less) Table 32. Experiment 17o-D. Exper imsntal design and distribution of an ima 1 s Sex No. of gilts No. of barrov;s \k% protein basal Treatments \kX protein DES+MT 12 ,2b 12a 12 ^ The carcass of one pig v.'as condemned for a condition of granuloma in the muscle tissue. Flavor and tenderness of meat from this carcass v.'as not determined. One pig died during the experiment. Apparent cause of death was generalized edema and congestive heart failure due to heat pros- tration. Due to loss of these data, orthogonality of the design was destroyed. Computer analysis using a complete and a reduced model was necessary in order to partition the sums of squares. For this reason, sums of squares generated from mean squares in the analysis of variance tables for Experiment 178""D are not additive. to .— C0vD>JD r-^vO r^r<^r^Lr\OOCOCr\rACMvDiriO-^Cr\CO'— r-~o^vDr^ocsit~ACN4co-TLA — -:roooo — o^coi Or>lo'>r^csiOv£)Crvvl3ro — CO. — .— orjcsjoD — •— •— — Lncoa\ II O CM oj- II II OQ. 3 (/) O 0) 0) I- u D C C 1- O O i/> •O 1 l- X ZJ o i~ a x: ftJO — uiJ3n3(DOCnEO<4- cn cn 0) 0) - >- >- 0) 0) 0) o o _ (U 1/1 u J_ XI 0 0 • — 0 T) ^ > O <^? d^ c--? ^ < -J o _i CCC^.'^-^^CC. >• o > o < Q. — -O Cl.>4- O _l S^ (K" i/l i/l 1/1 1/1 0) 0) 0 LTV , — 4J 0 0 0 TO 0 0 u- • in II II CM •— I/l CL. CL I/l OJ ^— ^ ■*w^ ■u 0] l- C c u a) TO TO •— ■tj 0 0 -0 4.1 •— *« c TO 14- 14- •*- 1- • .- •— c- r to >- Dl U) X »_ •^ •— X Q to 00 (0 J3 * •K 102 t) - en e o cN? v> cn •~ c 01 •— > in ^ U1 fO (U c 1- < ■o 0 E O 01 T) 0) — — — (v-1 LTV O O O O II II Ol. a. TO u TO o M- <+- C cn c irt (V O 1- -3- — — O O TO — CO x: ^ o 1^ t^ O CM a-\ — — u — — D Ol O (/) 1/1 0) (U o e o t- 1- — — — r^ lA _ o o o o u u a. Q- — — ' *j 'U c c TO 03 U o u- >4- •— •— c c C71 Dl o I/O ^: •K * ]0h I- o o •- QJ TD >- tt) <3v? C -o ♦— C 0 fij «- E o O L. "o fU o «-> £) Wi >- ra tt> o L. c < — c o — c 0) »_ o o •— c o (/) TO tn o \- fC -o O • (13 S_ -D C O C < O. fO o E O O 1- >- O O O jr V- 0) 4) >- c (U E vO (0 O E O U 0) I- 1- 0)M- — ^ sO „ — — vD O O — — — — — ca in 1/1 vi 1/1 o o O o o o n n a. O- ■>-> c ro o 4-> c TO o u- «4- c en c en 105 .— L. O 0) _j -o O E O Qj a) 0) V cnw- _ — — CM U1 1/1 in I/) LA O o d o n II Q. Q. 106 Table 38, Experiments I78-E and F. Experimental design^''-' and distri- bution^ of barrows over blocks and treatments Block Treatment ]k% protein basal ]k% protein DES + MI t5ll B12 B21 B22 B32 Total gain and urinary 17-ketosteroids were analyzed statistically with a randomized block design vnth 1 observation per experimental un i t . Daily feed intake, digestibility of dry matter and nitrogen, and g nitrogen retained/kg feed were analyzed statistically with a randomized block design with subsampl ing (6 observations per experi- mental unit. *- Subscript numbers indicate block and treatment, respectively; blocks consisted of littermate pairs of barrows. Table 39. Experiments I78-E and F. Summary of responses to treatments 178- ■E TRIAL 178" •F ■ -' ■ treatments treatments 1^^ P ]hZ P ]ii% P ]kZ P Response basal DES+HT basal DES+MT Average dai ly feed, Total gain, kg Dai ly N retent ion , feed kg g N/kg 1.65 7.38 10.88 1.53 7.15 7.69 2.53 9.53 10.86 2.0s 11.92 9.58 Apparent dig. d.m. , Apparent dig. ii , % 17-ketosteroids in , % 8'f.02 83. A6 4.3A 86.20 85.30 12.06=^ 87.17 8A.89 11.03 87.^9 84.61 6.47 urine, mg/day * Significant (P = 0.05 or less) 107 « — O X) — c >- >- — 03 < -3- CN >■ CJ r-~. LA f^ CX3 OO z O _ o~> _ r>.vr) CTv ^— -3- (SI r^ >- 4-> cr» CVJ O CA-T c OD CA r^ > a)<4- c <1) o F. _ l- u 1- — O TO O TO O 0) «- *-> ^ i_ 1- O — o — en (0 O — c v> 0) >- «- — 03 4_l ._ LPi r-- r-~ >— ro •U XI CO r-- o csj — TO — rr\ LA vO -T -3- E *- CO CM ^o — LA 2: O O -:3- o PA 01 LA r>-% LA CACO >- 4-' rA vD rv-> — r^ ^— c -=- r-- C^\ vD r-~ •— - o 109 31 31 •K * -K -K * oo 1/1 or CO in X XX * * ■IS ^; * X * CO to X Q- a: X X -K •!: 3Z 31 CO I/) -K * * X X X ■K ■K * X X X CL X O- tfl Q) 03 J3 Ifl •^ • in E ro J3 C X) I- I- TO CJ 0) O O Q) «- l- (J U »- O O m ui O O O ^^ X) OJ in ■ — -* I- I- o O .— o x> 1/1 (/) o u - -o (0 — — I o - X) E O (U 1- — E JT D o L. c 03 .- TO <+- 0) ._ . ds' "— (/I J3 TJ (D 0) E <+- 4-> •4-1 •!-> ^. t- X> Q. Q. in in 4-1 c 01 Ol o c 0) 4) OJ O O TO TO TO — c c — o t) >^ U1 >- >~x: JZ O O E (1) — '— c C C -U o o U1 (U o o u u u 4-> 1/1 n; E •— O t/1 f3 ID >. O *J U1 : c C 1- »- nj 0) ^ ^ — a. a Q) ■ ~ u — I. u ■o Q.M- 1- > o (3 o o o o o o o c^ e^ dx-> < _J o -J -J CL Q. _J _j ^<> e^ 5^ e o •— u U1 «D • l- O O O. T3 o *o ^ o o -j" -Q 0) tn in I/) in V 0) LA O O d o II II Q. Q- c c en o> 00 CO APPENDIX I I Figures HI P X H X S T Basal DES+HT Basal HORMONE LEVEL DES+MT 16% protein 12% protein ' Means v;ith the same superscript differ significantly (a,a=0.10 = 1,33). Figure 1. Experiment 178-A. The effect of interaction of sex, protein level, and hormone supplementation on dressing % \\n P X H X S DES+MT Basal DES+MT HORf-IONE LEVEL ]6% protein 12% protein ,a=0.10 = 3_]o. Figure 2. Experiment 178-A. The effect of interaction of sex, protein level, and hormone supplementa- tion on % lean primal cuts 113 Gilts Barrows SEX * Significant (P = 0.05 or less) Figure 3. Experiment I78-A. The effect of sex on % ham X\Ji H X S DES+MT HORMONE LEVEL Gilts «£» szs cr^ tsz^ C33 es> Barrows ^» Means v/ith the same superscripts differ s Iqni f leant Iv Figure ^. Experiment I78-A. The effect of interaction of sex and hor- mone supplementation on % loin 115 12 16 PROTEIN LEVEL, % ** Significant (P = 0.01 or less). Figure 5. Experiment 178-A. The effect of protein level on t picnic shoulder :u6 10 8 a. 9.31 ^vA 8.96 Basal DES+MT HORMONE LEVEL *" Significant (P = 0.01 or less). Figure 6. Experiment 178-A. The effect of hormone supplementation on % picnic shoulder 117 6.72*< It yn_ * Basal DES+HT HORMONE LEVEL ** Significant (P = 0.01 or less) Figure 7. Experiment 178-A, The effect of hormone supplementation on % Boston butt :M.8 p X s PROTEIN LEVEL, % Gilts Barrov/s ,0=0.10 = 0.35. Figure 8. Experiment 178-A. The effect of interaction of sex and protein level on ?; Boston butt 119 k.O 1^ 3.5 <) en to u « > < 3.0 12 16 PROTEIN LEVEL, % ** Significant (P = O.Cl or less) Figure 9. Experiment 178-A. The effect of protein level on average backfat thickness A.o 3.5 3.0 J^ t. 12.0 3.76 3.^0*A .^ Basal DES+MT HORMONE LEVEL ** Significant (P = 0.01 or less) Figure 10. Experiment 178-A. The effect of hormone supplementation on average backfat thickness 121 15 10 15.02 11.98 * 12 16 PROTEIN LEVEL, % * Significant (P = 0.05 or less) Figure I 1 , Experiment 178-A. The effect of protein level on loin eye marbl ing score J 22 o 1 ^ 1.0 0.5 0.0 Basal DES+MT HORf'.OME LEVEL Aroma Flavor *■* Significant (P = O.OI or less). Figure 12. Experiment 178-A. The effect of hormone supplementation on loin roast aroma and flavor score 123 ir 1.0 Gilts Barrows SEX * Significant (P = 0.05 or less) Figure 1 3. Experimant 178-B, The effect of sex on average daily gain 12A H X S ^ 3 Basal DES+MT HORMONE LEVEL Gilts Barrovvs a,b,c Means vjtth the same superscript differ significantly (^a=0.10 ^ 0.27). Figure U. Experiment 178-B. The effect of interaction of sex and hormone supplementation on average daily feed intake .125 .^ 3 Basal DES+MT HORMONE LEVEL ** Significant (P = 0,01 or less). Figure 15. Experiment 178-B. The effect of hormone supplementation on feed/gain 71 70 69 PROTEIN LEVEL, % Gilts Barrows a.b Means with the same superscript differ significantly Figure 16. Experiment 178-B, The effect of interaction of sex and protein level on dressing % 127 H X S 50 . .! ii8 . A6 DES+MT HORMONE LEVEL Gilts Barrows ^ Means with thr same superscript differ significantly ((,0=0. 10 ^ 2.15). Figure 17. Experiment 178-B. The effect of interaction of sex and hormone supplementation on % lean primal cuts 1.28 H X S 15.0 J H.5 1^.0 HORMONE LEVEL Gilts Barrows Means with th':> same superscript differ significantly (a,a-0.10 ^ 0.9)). Figure 18. Experiment 178-B. The effect of interaction of sex and hormone supplementation on Z loin 129 P X H H X S Basal DES+MT HORMONE LEVEL \^% protein ]2% protein Basal DES-:MT HOW^ONE LEVEL Gilts Barrov/s Means v;ith the same superscript differ significantly (a,a=0.10 = o./,2). Figure 19. Experiment 178-B, The effect of interaction of hormone supplementation with protein level and with sex on backfat thickness 130 P X H X S PROTEIN LEVEL, % Basal DES+MT Means with the same superscript differ significantly (0)0=0.10 = 3 1,3)^ Figure 20. Experiment 178-B. The effect of interaction of protein level, hormone supplementation, and sex on carcass length :i3i Gilts Barrows SEX * Significant (P = 0.05 or less) Figure 21. Experiment 178-B, The effect of sex on loin eye firmness score 132 1.5 1.0 0.5 0.0 Basal DES-f-MT HORMONE LEVEL Aroma Flavor *A Significant (P = 0.01 or less). Figure 22, Experiment 178-B. The effect of hormone supplementation on loin roast aroma and flavor score 133 H X S 0.90 ^ 0.80 0.70 Basal DES+MT HORMONE LEVEL Gilts Barrows ^» Means with the same superscript differ significantly (u.°=0.10 = 0.08). Figure 23- Experiment I78-D. The effect of interaction of sex and hormone supplementation on average dai ly gain 13^1 2.0 Gilts Barrows SEX * Significant (P = 0.05 or less) Figure 24. Experiment 178-D. The effect of sex on average daily feed intake 135 ID w > < 3.5 ^ ;.o „. 2.5 .. 3.12 2.65** Basal DES+MT HORMONE LEVEL ** Significant (P = 0.01 or less) Figure 25, Experiment 173-D. The effect of hormone supplementation on average daily feed intake 136 Basal DES+MT HORMOflE LEVEL *A Significant (P = 0.01 or less). Figure 26. Experiment I78-D, The effect of hormone supplementation on feed/gain 137 Basal DES+MT HORMONE LEVEL * Significant (P = 0.05 or less) Figure 27- Experiment 178-D. The effect of hormone supplementation on % lean primal cuts 138 H X S Basal DES+MT HORMONE LEVEL Gilts Barrov/s ^' Means with the same superscript differ significantly (a,a=0.10 = 0.8^). Figure 28- Experiment 178-D. The effect of interaction of sex and hormone supplementation on % ham -139 9.5 - u 9.0 8.5 5asal DES+MT HORMONE LEVEL ** Significant (P = O.OI or less) Figure 29. Experiment 178-D. The effect of hormone supplementation on % picnic shoulder 7.0 o 6.5 6.0 >" lAo 6.28 6.60^ ==J Basal DES+MT HORMONE LEVEL * Significant (P = 0.05 or less) Figure 30. Experiment 178-D. The effect of hormone supplementation on % Boston butt IM u ^■0 . 3.0 2.0 3.'>3 •f_. 3.01** Basal DES+MT HORMOtJE LEVEL ** Significant (P = 0.01 or less) Figure 31. Experiment 173-D. The effect of hormone supplementation on average backfat thickness ]li2 Gilts Ba r rows SEX * Significant (P = 0.05 or less) Figure 32. Experiment I78-D. The effect of sex on loin tenderness I**} 1.5 0.5 . 0.0 1.03 1.03 i I 1.22*'-^^ Basal DES+HT HORMONE LEVEL Aroma Flavor * Significant (P = 0.05 or less). ** Significant (P = 0.01 or less). Figure 33. Experiment 178-D. The effect of hormone supplementation on pork chop aroma and flavor score \kk 1.5 1.0 0.5 0.0 Basal DES-f-fIT HORMONE LEVEL Aroma Flavor * Significant (P = 0.05 or less) Figure 3';. Experiment 178-D, The effect of hormone supplementation on loin roast aroma and flavor score 1.A5 80 75 70 -. 75.81 70.71^= Gilts Barrows SEX * Significant (P = 0.05 or less) Figure 35. Experiment 178-D. The effect of sex on % protein in longiss imus dorsi (dry matter basis) Iii6 -I c Basal DES+HT HORMONE LEVEL * Significant (P = 0.05 or less). Figure 36. Experiment 178-D, The effect of hormone supplementation on % protein in long issimus dors i (dry matter basisT \hl JA 30 ^ -I 25 20 - 22. 8A 27.92** - ^ ' Gilts Barrows SEX ** Significant (P = 0.05 or less) Figure 37- Experiment 178-D. The effect of sex on % fat in long iss ini'js dorsi (dry matter basis) \hB (D E TO 25 -I .P 20 23.27 27.'f9ft Basal DES+MT HORMONE LEVEL * Significant (P = 0.05 or less). Figure 38. Experiment 178-D, The effect of hormone supplementation on % fat in longissimus dors i (dry matter bas is) LITERATURE CITED A.O.A.C. I9CO. Official Methods of Analysis (9th Ed.). Association of Official Agricultural Chemists. Washington, D.C. Applezweig, Norman. 1962. Steroid Drugs. McGrav/-Hill Book Co., Nev; York, p. 235-254. Baird, D. M. and H. C. McCanipbel 1 . 1959. Some effects of estrogenic, androgenic, and tranquilizer compounds on performance and carcass characteristics of grov.'ing-f inishing sv/inc. J. Anim. Sci. 18:1^95. Baker, D. H. , C. E. Jordan, V/. P. Waitt, and D. W. Gouwens. 1967. Effect of a combination of diethy 1st i 1 bestrol and rnsthyl- testosterone, sex, and dietary protein level on performance and carcass characteristics of finishing sv/ine. J. Anim. Sci. 26:1059. Baker, D. 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Feedstuffs 37:(2)l8. 156 Wallace, H. D. , A. Z. Palmer, J. W. Carpenter, L. A. Britt, A. C. V/arnick, and G. E. Combs. 1S67. Influence of protein level and hormone supplementation during the finishing period on fecdlot performance, carcass characteristics, and pork acceptability. Fla. Agr. Expt. Sta. Mimeo Series No. A.N67-IO. Weir, C. E. , A. Slover, C. Pohl , and G. D. Wilson. 1962. Effect of cooking procedures on the composition and organo- leptic properties of pork chops. Food Technol . 16:133. Whitchair, C-. K. , W. D. Gallup, and H. C. Bell. 1953. Effect of stilbcstrol on ration digestibility and on cal- cium, phosphorus, and nitrogen retention in lambs. J. Anim. Sci. 12:331. Whiteker, H. D. , H. Brov;n, C. E. Barnhart, J. D. Kemp, and U. Y. Varney. 1959. Effects of metfiylandrostenediol , methyl testosterone, and thyropiotein on growth and carcass chiaracter i st ics of swine. J. Anim. Sci. 18:1189. Williams, L. D. , A. M. Pearson, and N. B. V/ebb. 1963. Incidence of sex odor in boars, sows, barro./s, and gilts. J. Anim. Sci. 22:166. Wilson, J. D. 1962. Localization of the biochemical site of action of testosterone on protein synthesis in the seminal vesicle of the rat. J. Clin. Invest. M:153. Woehling, j-i. L. , G. D. Wilson, R. H. Gru;v,;ncr, R. W. Bray and L. E. Casida. 1951. Effects of stilbestrol and testosterone pellets implanted into growing-fattening pigs. J. Anim. Sci. 10:889. Wong, W. C. , W. J. Boylon, and S. C. Stothers. 1968. Effects of dietary protein level and sex on swine performance and carcass traits. Can. J. Anim. Sci. ^8:383. BIOGRAPHICAL SKETCH Ernest W. Lucas was born February 17, 19^2, in Boston, Massa- chusetts. In 1957 his family moved to California. He graduated from Rio Vista Joint Union High School in 19^0. In 1S6'; he received the Bachelor of Science degree, v/ith a major in Animal Husbandry, from California State Polytechnic College, San Luis Obispo, California. He worked as a graduate research assistant at Iowa State University from 196'i to 1567 and received the Master of Science degree, with a major in Animal Science, from that institution. From I967 to the present he has worked as a graduate research assistant at the Univer- sity of Florida while studying tavard the degree of Doctor of Philosophy, majoring in Animal Science. He has specialized in swine nutrition in his advanced v;ork. He is a member of the fraternity of Alpha Zeta and of the American Society of Animal Science. Ernest V.'. Lucas is married to the former Barbara Damlos, who is from San Francisco, California. r57 This dissertation v;3s prepared under the direction of the chairman of the candidcJte's supervisory corr,;iii ttee and has been approved by all meinbers of that coi.-.iiii ttee. It v/as submitted to the Dean of the College of Agriculture and to the Graduate Council, and v/as approved as partial fulfillment of the requirements for the degree of Doctor of Philosophy. June, 1970 Supervisory Committee: '^^uIm M-IL y^y '> ■cO^L^i^ Dean, College of Agricul Dean, Graduate School t bdU ■ ■ ■ ■