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The influence of delayed bleeding on characteristics of bovine longissimus and biceps femoris muscles from 39 heifers and 36 steers was studied. Animals were stunned with a captive bolt stunner and controls were bled immediately after stunning by severing the carotid arteries and jugular veins. Experimental heifers were bled 3 or 6 min after stunning, and the experimental steers were bled 3 or 30 min after stunning by severing the atlas joint and removing the head. Collected blood represented 5.6, 3.9 and 3.7% of the heifer carcass weight for control, 3-min and 6-min groups and 5.9, 4.9 and 4.1% of the steer carcass weight for control, 3-min and 30-min groups, respectively. Pluck and liver weights did not vary among treatments for steers or heifers, but spleen weights tended to be heavier in animals where bleeding was delayed after stunning. Delayed bleeding did not influence cooler shrink, muscle pH, fat color, microbial growth, waterholding capacity or percentages of sarcoplasmic protein, total protein, moisture or intramuscular fat in the muscles studied. Muscles from heifers decapitated 6 min after stunning had more Fe than muscles from heifers in control or 3-min experimental groups, but delayed bleeding did not influence Fe in muscle from steers. Overall, delayed bleeding after stunning decreased the weight of blood lost and tended to increase carcass weight and spleen weight, but had very little influence upon characteristics of the two muscles studied.

Effects of sex, diet, breed, weight group and geographical location on fatty acid composition, fat color and fat firmness were examined in a factorially arranged experiment involving 32 ram and 32 wether lambs. Thirty-two Suffolksired and 32 Rambouillet-sired lambs out of Finn × white-faced (mixed breeding) ewes were fed a high or a low energy diet at the MARC or the University of Wyoming. Lambs were slaughtered in two weight groups at 63 and 76 kilograms. Ram carcasses had softer, yellower fat than wether carcasses and lambs fed the high energy diet had softer, yellower fat than lambs fed the low energy diet. Fat from rams was higher (P<.05) in branched chain fatty acids and shorter chain fatty acids with odd numbers of carbon atoms, but lower in 16:0 and 18:0 than was fat from wethers. Feeding lambs a high energy diet also increased (P<.05) levels of odd-numbered and branched chain fatty acids. The effect of sex and diet on levels of 16:0, 18:0, odd-numbered and branched chain fatty acids appeared to be additive. Weight group, breed and location had little effect on fatty acid composition, fat firmness or fat color, but some weight X location interactions were significant.

Shorn Western, white-faced cull range ewes approximately 6 yr of age were slaughtered and factors affecting yield, composition, and quality of the lean were studied. Weight of lean from the leg, loin, rib and shoulder of medium-conditioned ewes was higher than that from poor-conditioned ewes, but the lean from medium-conditioned ewes contained more fat. Hot-boning or simply stripping the fell and subcutaneous fat from hot carcasses reduced fat content of meat from medium-conditioned carcasses because fat was more completely removed. Collagen content of lean from the leg, loin, rib and shoulder of medium-conditioned ewes was lower than that from poor-conditioned ewes. Mutton frames included all the bones in the carcass, muscles that are typically left on bones during boning operations, and all muscles on the neck, fore shanks and hind shanks. Approximately half of the frame weight could be recovered as mechanically separated mutton (MSM). Collagen content of MSM did not vary greatly by ewe condition or by hot or cold boning methods. Overall, medium-conditioned ewes are more desirable than poor-conditioned ewes because they yield greater amounts of lean that is lower in connective tissue.

Seventy-two Rambouillet ewes were fed one of two different levels of energy and protein during gestation to determine the effects of maternal undernutrition on growth and development in their offspring. Levels of energy and protein for the two groups of ewes were: 1) 70% of National Research Council (NRC) requirements 30 d prior to breeding and the first 100 d of gestation and then alfalfa hay fed at 70% of the average consumed by group 2, and 2) 100% of NRC requirements 30 d prior to breeding and throughout gestation. Dissection data from the leg and muscle characteristics were recorded for each lamb. Neither dissected muscle and fat percentages nor proximate analyses of dissected muscles was influenced by ewe undernutrition during early pregnancy. However, the reduced conception rate, increased embryonic/fetal mortality, decreased birth weights and increased lamb mortality resulted in a severe reduction in kilograms of lamb per ewe bred. Feeding ewes 70% of NRC requirements during gestation resulted in lambs with heavier semitendinosus muscle weights, larger muscle fiber diameters and shorter sarcomere lengths than in lambs from adequately fed ewes. No influence of ewe diet, birth type or sex was observed for proportions of muscle fiber type (βR, αR or αW). Therefore, low level feeding of ewes during early gestation had no detrimental effects on the carcass or muscle fiber characteristics of their lambs at slaughter.

Twenty Good grade bulls and heifers approximately 18 mo of age from the university crossbred beef herd were stunned and monitored for heart rate by radiotelemetry until ventricular activity ceased. The animals ranged in weight from 335 to 470 kg and were stunned with a captive bolt stunner and allotted to different bleeding treatments. Control animals (three bulls and two heifers) were bled immediately by severing the carotid arteries and jugular veins. The other animals were decapitated by severing the atlas joint and removing the head without previously severing the carotid arteries and jugular veins. Time periods after stunning were 0 min (two bulls), 3 min (two bulls and two heifers), 6 min (two bulls and one heifer), 15 min (three heifers with foreshanks removed immediately after stunning) and 15 min (three heifers pithed and foreshanks removed immediately after stunning). Respiration ceased in all animals when they were stunned and did not resume. Duration of heart activity after stunning was greater in animals in which bleeding was delayed than in control animals. Weight of blood removed from animals decreased as the time between stunning and bleeding increased. Heart activity ceased 8 to 10 min after stunning in animals decapitated 15 min after stunning. Therefore, the majority of blood was removed without ventricular pumping.

Each of 58 blackface and 59 whiteface whether lambs was allotted to one of four nutritional treatments: chopped alfalfa hay, alfalfa hay cubes, pelleted alfalfa hay or a pelleted diet of hay, oats and barley. Lambs fed the chopped hay and hay cubes had lighter carcass weights, less intramuscular fat in the longissimusmuscle, smaller loineyes, darker colored lean and lower quality grades than lambs fed the two pelleted diets. Fasting the lambs for 72 hr resulted in less fat, darker lean, decreased blood plasma fatty acid concentrations of C18:2 and C18:3, increased concentrations of C18:l and C18:0 and increased blood ketone concentrations. Interactions (P<.05) between diet and fasting occurred. During fasting, fat decreased more on fatter lambs that had been fed pelleted hay and pelleted hay and grain than in leaner lambs fed chopped hay and cubed hay diets. Marbling decreased most during fasting in meat from lambs fed the chopped hay diet. Darkness increased during fasting in meat from lambs on all diets except the hay and grain pellet.

Performance tests with ram lambs were conducted in 1975, 1976 and 1977, and ensuring progeny tests were carried out in 1977, 1978 and 1979. The ram lambs were of three breed groups: Suffolk, Columbia and triplet (western white-faced sheep selected for multiple birth). Performance was evaluated with an index combining postweaning growth rate to 72.5 kg and fat depth. Approximately the top one-third of each ram breed group was selected for progeny testing. All male (wether) progeny were fed to 64 kg, then sheared and slaughtered, and their carcasses were evaluated. Suffolk-sired lambs were superior to lambs sired by triplet or Columbia rams in growth rate and carcass desirability. Columbia-sired and triplet-sired lambs reflected a year × breed of sire interaction, with no overall advantage for either group. Significant sire differences were apparent in production traits as well as carcass traits. Most rams sired lambs with desirable carcasses at heavy weights, but in some sire groups, most of the carcasses were overfinished. Sire and progeny performance indexes were significantly correlated, but selection on the basis of sire performance records did not ensure desirable carcasses among progeny. Year × breed of sire interactions were significant for fat depth and slaughter age. Twins had lower weaning weights than single lambs and thus were older at slaughter and sheared heavier fleeces, but differences due to type of birth in feedlot gain or carcass measurements were not significant. Feed efficiency decreased with increasing weight and time in the feedlot.

Regression analyses of compositional traits on hot carcass weight (HCW) was performed on 120 Suffolk, Hampshire and reciprocal cross ram lambs slaughtered at average ages of 26. 34 or 42 weeks. Seventy-two carcasses were sub-sampled for palatability traits and aroma of the cooked fat, and the data were analyzed by regression and correlation procedures. HCW ranged from 16 to 51 kg, and the least squares mean and standard error was 35.5 kg ± 7.4 kilograms. All compositional traits measured in terms of weight, depth or area increased linearly (P<01) with increasing HCW. A 10 kg increment in HCW resulted in a 5.46 kg increment in retail primal cuts. The conclusion was that the ram carcasses in the weight range evaluated have a very acceptable lean content.Color of lean was the only carcass quality trait that did not vary significantly (P>.05) with variation in HCW. Aroma score (6.01) and panel scores for juiciness (5.80) and flavor (5.62) were low but they were not significantly influenced by HCW. Tenderness scores decreased (P<.01) as HCW increased. Quality grade was negatively correlated (overall) with tenderness, juiciness and overall acceptability (r = −.31, −.26 and −.26, respectively, P<05).

Composition of hand boned meat, mechanically deboned meat and bone residue from 12 different groups of veal, beef and pork bones were studied to determine potential edible protein yields from bones destined for rendering. Yield of mechanically deboned meat was higher than was possible when the bones were hand cleaned of all visible lean, fat and tendon. Percentage protein in mechanically deboned meat was lower and fat content was higher when compared to hand boned meat. Differences were due to bone marrow which was extracted as deboned meat and to connective tissue which was removed from the meat during mechanical deboning. Fluoride content of mechanically deboned meat was higher than hand boned meat but most of the fluoride was discarded as part of the bone residue.

Meat from ram lambs of three different carcass weight groups (29.3, 39.0 and 43.1 kg) and a control group of market weight wethers (23 kg carcass weight) was evaluated. Wethers were more acceptable in tenderness and juiciness than ram lambs in the 39.0 and 43.1 kg weight groups. Flavor and aroma scores for all three ram groups were inferior to the scores for meat from wethers. Within the ram lamb slaughter groups, the youngest and lightest rams were the most acceptable in tenderness.

Fifty wethers and 51 spring-born rams were divided into five groups and slaughtered at different seasons of the year at average ages of 271, 361, 459, 557 or 652 d to determine the age and season at which differences in secondary sex characteristics could be detected. Serum testosterone concentrations and testes weights were low in January when the rams were 271 d of age and again in April at 361 d of age. By July, at 459 d of age, testosterone concentrations and testes weights had peaked and then decreased the following November at 557 d and February at 652 d. In contrast with plasma testosterone concentrations and testes weights, buckiness scores, splenius to semimembranosus or semitendinosus muscle ratios, splenius muscle weights and neck and shoulder percentages were not seasonal. All of these measures increased significantly up to July and continued to increase slowly, but not significantly, thereafter. Muscle color and texture scores and rib eye color scores tended to increase in a linear manner for both rams and wethers as age increased. Subcutaneous fat from rams was yellower and softer than that from wethers over all age groups. Ram fat firmness did not change (P> .05) with age, and the only significant change in ram fat color was between the groups at 271 and 361 d of age. Overall, season of year coupled with higher levels of serum testosterone was related to initial development of secondary sex characteristics in ram lambs.

Fifty-one ewes, 50 wethers and 51 rams of Finn × whiteface or Suffolk × whiteface breeding were slaughtered at an average age of 271, 361, 459, 557 or 652 d to study changes in maturity characteristics with changes in age. When metacarpal epiphyseal cartilage (growth plates) ossifies with age, break joints on the distal end of the metacarpals fuse and the end of the bone then appears as a spool joint rather than as a break joint. This fusion occurs earlier chronologically in ewes than in rams or wethers. Most Finn × whiteface-cross ewes, which normally reach reproductive maturity earlier than Suffolk × whiteface-cross ewes, exhibited ossified metacarpal growth plates by 459 d of age; break joints of Suffolk × whiteface crosses were not fused until 557 d of age. Both breed groups of rams exhibited fused joints by 557 d of age, but only 3 of 10 wethers exhibited spool joints at 652 d of age. Microscopic examination showed that even in these three wethers the epiphyseal growth plate could still be detected. Yearling 2-yr-old classifications of sheep from teeth were not gender-dependent within the discrete age classes of this study. About half the sheep in each gender group were classified as yearlings at 459 d of age and about half in each group were classified as 2-yr-olds by 652 d of age. Stepwise multiple regression equations to estimate age of sheep in days were developed. Overall maturity, lean color and texture and rib bone maturity were the best carcass measures of maturity. Maturity scores for characteristics of the break joint did not enter any of the equations studied. When eye lens weight was included in equations with the best measures of carcass maturity, accuracy of estimates for age of sheep was improved.

Whole cervical and lumbar vertebrae, ribs and femurs from 12 ovine, eight porcine and 14 bovine carcasses and whole cervical vertebrae, ribs, femurs and synsacrums from eight chickens and eight turkeys were removed from animals slaughtered at different chronological ages. Large increases in fat and dry matter with increased age were found in cervical and lumbar vertebrae, ribs and femurs from ovine, porcine and bovine carcasses. In chickens and turkeys, dry matter increased with age but fat in fresh bone remained relatively constant. In all five species dry-fat-free bone decreased in percent nitrogen and increased in ash and calcium as age increased. Percent calcium in bone ash was similar for all age groups of all species except turkeys and for all four bones studied. Calcium to nitrogen ratio increased with age. Significant differences in composition of bones within animals were evident. Rib bones had the lowest fat percentage and femurs had the highest fat and dry matter percentage in cattle and sheep. Ribs, partially because of high ash content, usually contained more dry matter than lumbar and cervical vertebrae. In general, femurs possessed the least nitrogen and the most ash of any of the bones studied. Hydroxyproline content, on a dry-fat-free basis, did not differ significantly according to age or bone in the red meat species. Nutritional value of bone protein from all five species was low when based upon hydroxyproline analysis. Calcium or ash could be useful in studying changes in bone maturity. These bone components could also be used to estimate amount of bone in mechanically deboned meat.

In this trial 63 Western whiteface wether lambs were used in a 2 × 2 factorial design arrangement to study the effects of two dietary protein levels (10.5 and 13.5%) and two dietary energy levels (50:50 and 80:20 ratio of concentrate to roughage) on live traits and carcass composition. All lambs were slaughtered at a constant weight of approximately 60 kilograms.Live traits were affected most by changes in protein and energy levels. Increasing protein levels resulted in higher average daily gains and improved feed efficiencies. As energy content of the diets increased, days on feed increased while feed consumption decreased. Feed efficiency improved as energy levels increased. Preslaughter shrink increased as energy level in the diets decreased. Carcass measurements, quality factors and chemical composition of carcass were not affected by changes in protein and energy levels.Significant interactions between protein and energy levels in the ration were noted for kidney fat weight, percent kidney fat, body wall thickness and yield grade. As percent protein in the diets increased, carcass fat measures increased on the low energy diets but decreased on the high energy diets. As energy level in the diets increased, carcass fat measures increased on the low protein diets but decreased on the high protein diets.

Data were collected on 64 ram and 564 wether and ewe carcasses. Simple carcass measurements were useful in developing equations for estimating percent fat, weight of retail cuts and percent retail cuts. The equation using body wall thickness and fat depth 3.8 cm. from the midline between the 12th and 13th ribs had multiple correlations of 0.72 and 0.87 and standard error of estimates of 2.95 and 3.90 for predicting percent fat in the boneless carcass of ewes and wethers and rams, respectively. Carcass weight, body wall thickness and fat depth 3.8 cm. from the midline between the 12th and 13th ribs had a multiple correlation of 0.84 and a standard error of estimate of 0.34 for estimating kilograms of retail cuts from lamb carcasses. Carcass weight and body wall thickness had a multiple correlation of 0.99 and a standard error of 0.44 for predicting kilograms of retail cuts of ram carcasses. Body wall thickness, kidney weight and fat depth 3.8 cm. from the midline between the 12th and 13th ribs had a multiple correlation of 0.73 and a standard error of 1.47 for estimating percent retail cuts from lamb carcasses. The equations mentioned in this summary indicate that percent fat, percent retail cuts and weight of retail cuts can be estimated without breaking the carcass or by using subjective measurements.

Data were collected on 802 offspring from 58 sire groups. Heritability estimates as calculated by paternal half-sib correlations were generally higher and had lower standard errors than comparable estimates calculated by regression of offspring on sire. Heritability estimates were relatively high for measures of fat, lean and tenderness. Estimates of heritability were relatively low for quality traits. Heritability estimates for wool traits were lower than those reported by previous researchers. The high heritability estimates for traits of carcass merit are encouraging from the standpoint of progress that can be made by selection.

FORTY-THREE wether lambs weighing 50 kg, and 47 wethers and 50 rams weighing 65 and 68 kg, respectively, were used to evaluate the effects of weight and castration on carcass composition, fatty acid composition and palatability. Light wethers (50 kg) were superior in cutability to heavy wethers (65 kg). Heavy rams (68 kg) were superior to heavy wethers (65 kg) in cutability.Percent myristic, palmitic and stearic decreased as weight and age increased and total percent unsaturates increased proportionally. There were no significant differences in intramuscular fatty acids due to castration. Kidney fat from rams contained significantly (P<.05) less 18:0 than that from heavy wethers. Subcutaneous fat from rams contained significantly (P<.05) more myristic and palmitic than that from heavy wethers.Taste panel results indicated that both light wethers and rams were significantly (P<.05) less tender than heavy wethers. However, rams were comparable to light wethers in all palatability traits studied.

Twenty-six ram and wether lambs were used to evaluate effects of testosterone on carcass composition, fatty acid composition, flavor and tenderness.Significant differences (P<.05) were observed between treated rams and untreated wethers in thickness, color and firmness of fat. Testosterone enanthate treated wethers and normal rams were remarkably similar in all carcass traits, especially fat thickness, kidney fat weight, fat color and fat firmness. However, the untreated rams gained significantly (P<.05) faster than the treated wethers.Percent 14:0, 16:0 and 18:0 decreased in all treatments as weight and age increased and total percent unsaturates increased proportionally. Greatest changes in fatty acid composition occurred between 57 and 68 kg live weight when lambs were between 7 and 8½ months of age.At 68 kg, treated rams' fat contained significantly (P<.05) more 15:0 and 17:1 and less 16:0 than other groups. Differences in short chain fatty acids (

Data from 802 lambs representing 58 sire groups were analyzed to determine relationships between live and carcass traits. Genetic correlations indicated some antagonism between fleece growth and body growth (weaning weight and A.D.G. on test) for lambs fed to a relatively constant weight.Negative genetic correlations were also found between fleece weights or staple length and traits related to carcass meatiness (longissimusarea and retail cut weight). Genetic correlations between amount of fat and amount of lean were negative. No serious antagonism was apparent between growth rate and carcass desirability. Consequences of negative relationships between important traits were discussed.

EIGHTY-SIX wether lambs were used to evaluate effects of reduced energy intake on carcass composition, fatty acid composition and palatability.Reduced energy intake had a detrimental effect on slaughter weight, carcass weight, longissimusmuscle area, leg conformation score, carcass grade, marbling score, color of lean and yield of both wholesale and retail cuts. Fat thickness and kidney fat weight of the stressed lambs were also reduced.Only minor differences were observed in fatty acid composition of intramuscular, subcutaneous and kidney fat.The diet-stressed lambs received significantly (P<.05) higher scores for tenderness than the control lambs. No differences between stressed and control lambs were found for flavor, juiciness, overall satisfaction or fat flavor.