|Roeder, Richard - UNIVERSITY OF IDAHO|
|Roader, M - UNIVERSITY OF IDAHO|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 22, 2000
Publication Date: February 1, 2001
Citation: GRINGS, E.E., SHORT, R., MACNEIL, M.D., ROEDER, R.A., ROADER, M.J. INTERACTIONS IN POSTWEANING PRODUCTION OF F1 CATTLE FROM HEREFORD, LIMOUSIN, OR PIEDMONTESE SIRES. JOURNAL OF ANIMAL SCIENCE. 2001. v. 79. p. 317-324. Interpretive Summary: Use of cattle breeds that express various degrees of muscle hypertrophy may be a way to increase production of a lean product. Meat from cattle heterozygous for this major gene may be more tender than that from cattle that do not have this gene. Information is needed on the production characteristics of cattle with the genetic potential for muscular hypertrophy and the interaction with other management strategies. The objective of this study was to evaluate the interactions of castration, dietary protein, and feeding length on growth and carcass characteristics of male cattle of three breeds that vary in degree of muscularity. Sire breed, gender and length of finish all impacted carcass traits, however, numerous interactions among these effects for production traits requires careful evaluation of the growing and finishing strategies used in producing carcasses from various types of cattle. Altering the length of finish had a greater effect than gender for weight characteristics, such as slaughter weight, hot carcass weight, and dressing percentage, whereas gender had more effect on individual carcass components. The interaction of sire breed with length of finish and with gender for several carcass traits, indicates a potential advantage to tailoring postweaning management to animal genotype for the production of meat, even for cattle of similar mature weight.
Technical Abstract: A 2-yr study was conducted to evaluate the interactions of castration, dietary CP, and feeding length on growth and carcass characteristics of male cattle that vary in expression of muscular hypertrophy. Crossbred cows were bred by AI to Hereford, Limousin, or Piedmontese bulls, which represented genotypes with normal, moderate, and hyper muscularity, respectively, but with similar mature weights. Male calves were either castrated at 30 to 60 d of age or left intact. After weaning each year, 131 male calves were placed into pens having individual electronic feeding gates. Calves were fed growing diets until reaching 386 kg BW and then switched to finishing diets for 90 or 132 d. There were many interactions among sire breed, gender, and feeding length on carcass composition. Bulls were more efficient than steers in producing live weight gain. Length of finish accounted for a larger source of variance than gender for weight characteristics, whereas gender was the larger source of variation for carcass composition. Level or degradability of dietary CP influenced rate of gain from weaning to 386 kg but had no effect on growth during the finishing phase or on carcass characteristics. Differences in carcass characteristics among calves of different sire breeds indicate differences in mode of expression of muscularity in various breeds of cattle and that cattle of these breeds may benefit from different management strategies.