Effects of Compudose® implants from birth to slaughter on carcass and meat traits of young bulls and steers

Implanting young bulls with Compudose® three times from birth to slaughter resulted in performance similar to that of nonimplanted bulls, but decreased masculinity development. Implanted bulls tended to have higher marbling scores, more tender meat, more youthful carcasses, and lighter lean color than nonimplanted bulls. Although both implanted and nonimplanted bulls were more efficient and gained faster in the feedlot than implanted steers, the steers showed very little carcass masculinity and had finer-textured lean. Implanted steers had more youthful carcasses and lower Warner-Bratzler shear values than nonimplanted bulls. However, nonimplanted bulls grew faster, were more efficient, had larger ribeyes and lower yield grade numbers than implanted steers. For large-framed cattle, castration and implanting with Compudose® near birth result in the most desirable combination of performance, carcass, and meat quality traits

Effects of Compudose® implants from birth to slaughter on carcass and meat traits of young bulls and steers

Implanting young bulls with Compudose® three times from birth to slaughter resulted in performance similar to that of nonimplanted bulls, but decreased masculinity development. Implanted bulls tended to have higher marbling scores, more tender meat, more youthful carcasses, and lighter lean color than nonimplanted bulls. Although both implanted and nonimplanted bulls were more efficient and gained faster in the feedlot than implanted steers, the steers showed very little carcass masculinity and had finer-textured lean. Implanted steers had more youthful carcasses and lower Warner-Bratzler shear values than nonimplanted bulls. However, nonimplanted bulls grew faster, were more efficient, had larger ribeyes and lower yield grade numbers than implanted steers. For large-framed cattle, castration and implanting with Compudose® near birth result in the most desirable combination of performance, carcass, and meat quality traits

Managing fast- vs. slow-growth genotypes to optimize quality and yield grades

Fast-growth genotype steers placed on a high energy ration a month after weaning were compared to a slow-growth genotype on a growing ration for 155 days, followed by a finishing ration for 62 days. The fast-growth genotype produced heavier, higher quality carcasses in less time than the slow-growth genotype, with similar energy conversion. Using contemporary prices. the fast-growth genotype cattle broke even, and the slow-growth genotype lost $124 per head

Relationship of Warner-Bratzler shear force and trained sensory panel tenderness of strip loin steaks cooked to 131 and 158°F

In a previous study, eighteen strip loins from USDA Select and premium Choice carcasses were cooked on a Magikitch’n® belt grill to determine tenderness at nine different endpoint temperatures. That study revealed that optimum Warner-Bratzler shear force (WBSF) values occurred in strip loin steaks cooked to 131°F, but current WBSF protocol requires steaks to be cooked to 158°F. Therefore, trials employing trained sensory panels (TSP) were conducted to determine the relationship of WBSF with TSP tenderness from steaks cooked to 131 and 158°F on the belt grill. As expected, panelists found steaks cooked to 131°F more tender than those cooked to 158°F. The relationship of WBSF with TSP ratings for tenderness was not significant (P>0.05) when both steaks were cooked to 158°F. When both steaks were cooked to 131°F, however, there was a moderate relationship (r = -0.52) of WBSF with TSP tenderness. The relationship of WBSF from steaks cooked to 131°F with TSP ratings for tenderness from steaks cooked to 158°F was the strongest (r = -0.66). More research is needed to determine the feasibility of cooking steaks to 131°F, rather than 158°F, to improve WBSF determination

Reliability of U.S.D.A. beef carcass yield grades in reflecting differences in retail yields

Retail cut-out and U.S.D.A. yield grade data were obtained on 1,121 carcasses of steers from Hereford and Angus dams mated artificially to Hereford, Angus, Jersey, Limousin, South Devon, Simmental and Charolais bulls. Calves were weaned when approximately 215 days old, conditioned 28 days, fed an average of 218 days after weaning before being slaughtered in a commercial slaughter plant. Carcass cooler data were obtained and the right side of each carcass was cut into closely trimmed, essentially boneless retail cuts at the KSU food service building. Beef yield grades do reflect definite differences in retail yields. Statistical tests indicated less than one chance in 1,000 that such differences occurred by chance and that the yield grade differences were real. The average difference in retail product percentage between yield grades was 4.6 percent. The average difference in fat trim percentage was 5.6 percent. For 700-pound carcasses, that\u27s a difference of 39.2 pounds of waste fat, or 32.2 pounds of retail product. The difference in bone percentage would account for the other 7 pounds

Endpoint temperature, cooking method, and marbling degree have different effects on Warner-Bratzler shear force of beef strip loin, bottom round, and brisket muscles

Our objective was to determine the effects of endpoint temperature, cooking method, and marbling on Warner-Bratzler shear force (WBSF; an objective method for determining tenderness) of three beef muscles. Eighteen subprimals of a muscle containing low content of connective tissue, longissimus lumborum (strip loin), and two muscles containing a high content of connective tissue, biceps femoris (bottom round) and deep pectoralis (brisket), were selected from USDA Select and Choice (Certified Angus Beef) carcasses. After 14 days of aging, subprimals were frozen, fabricated into steaks, and stored frozen until cooking. Steaks were assigned to one of two cooking methods, the Magikitch’n® electric belt grill (a rapid conduction method) or a water bath (a slower, convection method); and one of nine endpoint cooking temperatures, 104, 113, 122, 131, 140, 149, 158, 167, or 176°F. According to WBSF results, optimum tenderness for the strip loin occurred around 131°F. Higher marbling protected tenderness at higher endpoint temperatures. Tenderness increased in bottom round and brisket muscles as endpoint temperature increased from 104 to 140°F, then tenderness decreased as endpoint temperature rose from 149 to 176°F. Endpoint temperature was the only significant factor affecting bottom round tenderness. Steaks cooked in the water bath had higher WBSF and, therefore, were less tender than those cooked on the belt grill. This was true for both the strip loin and brisket. The effect of increasing endpoint temperature on WBSF of the strip loin was different than for the bottom round and brisket

Comparison of feedlot and carcass characteristics of Angus, Hereford, Brahman, Charolais, and Gelbvieh crossbred steers

Feedlot performance of 207 steers with various percentages of Angus, Hereford, Charolais, Brahman, and Gelbvieh breeding were compared at a constant 1) days fed, 2) adjusted carcass backfat, and 3) slaughter weight. As the percentage of Angus, Hereford, or Brahman increased, growth rate decreased, whereas increasing the percentage of Charolais increased growth rate. Increasing the percentage of Gelbvieh increased weaning weight but had little effect on post-weaning gains. Increasing percentage of Charolais increased feed conversion efficiency, whereas the other breeds were similar, except that at a constant slaughter weight, greater percentage of Hereford improved feed conversion efficiency. Increasing the percentage of Charolais increased carcass weight and ribeye area and decreased yield grade, but marbling was not different from that of Angus. An increase in percentage of Hereford caused a decrease in carcass weight, ribeye area, marbling, and quality grade. Increasing percentage of Angus decreased carcass weight and ribeye area but increased marbling and quality grade. Increasing percentage of Brahman caused the greatest reduction of marbling and quality grade of any breed. Increasing the percentage Gelbvieh breeding resulted in increased ribeye area and decreased marbling at constant days fed and slaughter weight

Estimates of parameters between direct and maternal genetic effects for weaning weight and genetic effects for carcass traits in crossbred cattle

Estimates of heritabilities and genetic correlations were obtained from weaning weight records of 23,681 crossbred steers and heifers, and carcass data of 4,094 crossbred steers using REML applied to animal models. Direct and maternal heritabilities for weaning weight were 0.14 and 0.19, respectively. The genetic correlation between direct and maternal weaning weight was negative (-0.18). Heritabilities for carcass traits of steers were moderate to large (0.34 to 0.60). Genetic correlations between direct genetic effects for weaning weight and carcass traits were small, except with hot carcass weight (0.70), ribeye area (0.29) and adjusted fat thickness (0.26). Genetic correlations of maternal genetic effects for weaning weight with direct genetic effects for carcass traits were: hot carcass weight (0.61), retail product percentage (-0.33), fat percentage (0.33), ribeye area (0.29), marbling score (0.28), and adjusted fat thickness (0.25). These results indicate that maternal genetic effects for weaning weight may be correlated with genetics for propensity to fatten in steers. Selection for only direct weaning weight would be expected to increase carcass weight and ribeye area and slightly decrease marbling and retail product percentage. Selection for either increased maternal or direct weaning weight would be expected to result in increased carcass weight, ribeye area, and fat thickness, but would not be expected to affect tenderness

Breeding for Lean Beef (Germ Plasm Evaluation Program)

Historically, when steers were finished on pasture, ability to finish at a young age was desirable, particularly when market requirements for fatness were great. However, ability to fatten became a handicap as we shifted to increased use of concentrate feeds in diets of growing-finishing cattle. Consequently, yield grades were added to the USDA grading system to reflect variation in carcass value associated with differences in yield of retail product. Recently, consumer pressure to reduce caloric and fat content of beef and other red meats has intensified because coronary heart disease is believed to be associated with elevated blood-cholesterol levels. Cholesterol levels are, in turn, associated with dietary intake of saturated fat. Dietary control of the type and amount of fat consumed is strongly recommended by members of the medical profession in an attempt to regulate blood-cholesterol levels. The purpose of this paper is to examine genetic variation among and within breeds in the amount and distribution of fat and lean in beef carcasses and to evaluate opportunities to genetically change fat and caloric content of retail product in cattle

Germ Plasm Evaluation Program- Progress Report No. 12

Breed differences in performance characteristics are an important genetic resource for improving efficiency of beef production. Diverse breeds are required to exploit heterosis and complementarity through crossbreeding and to match genetic potential with diverse markets, feed resources and climates. This report presents preliminary results from an ongoing study at the Roman L. Hruska U.S. Meat Animal Research Center to characterize breeds of cattle representing different biological types for traits that influence quantity and value of production. Experimental Procedure: The Germ Plasm Evaluation (GPE) program has been conducted in four cycles. Table 1 shows the mating plan for cycles I, II, III, and IV. Each cycle was initiated by mating Hereford and Angus cows by artificial insemination (AI) to sires of diverse breeds. Semen from the same Hereford and Angus bulls has been used throughout to produce control Hereford-Angus (original HAx, sires born 1968-70) reciprocal crosses in each cycle. In cycle IV, new samples of Hereford and Angus (current HAx, sires born 1982-84) bulls were added to evaluate genetic trends within these breeds. In cycle IV, semen from 14 original control Angus, 11 original control Hereford, 30 current Angus, 32 current Hereford (14 horned and 18 polled), 29 Longhorn, 24 Piedmontese, 31 Charolais, 29 Salers, 31 Galloway, 22 Nel1ore, and 26 Shorthorn bulls is being used by AI to produce about 200 calves per sire breed in five calf crops (1986-1990). Following an AI period of about 45 days, one or two bulls each of Angus, Hereford, Charolais, Gelbvieh, and Pinzgauer bulls are used each year by natural service in single-sire breeding pastures for about 21 days. These breeds are being used in clean-up matings to increase ties to previous cycles and facilitate eventual pooling of results over all four cycles