Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/25/2009
Publication Date: 1/1/2010
Citation: Casas, E., Thallman, R.M., Kuehn, L.A., Cundiff, L.V. 2010. Postweaning Growth and Carcass Traits in Crossbred Cattle from Hereford, Angus, Brangus, Beefmaster, Bonsmara, and Romosinuano Maternal Grandsires. Journal of Animal Science. 88(1):102-108. Interpretive Summary: The beef industry is under increasing pressure to produce high quality beef. The objective of this project was to evaluate carcass composition traits produced by grand-offspring from tropically adapted Bos taurus breeds, to be used by U.S. producers. Differences in carcass composition were assessed in offspring of crossbred cows mated to Charolais or MARC III sires. Crossbred cows were produced by mating Hereford, Angus, Beefmaster, Brangus, Bonsmara, and Romosinuano sires, to Angus and MARC III cows. Animals with Angus grandsires grew faster than other breeds, had the heaviest carcasses, with the most desirable carcass characteristics. Crossbreeding programs including Romosinuano or Bonsmara may have to incorporate breeds of larger size to compensate for their smaller size. Brangus and Beefmaster are intermediate in fat deposition, and competitive in meat production. The latter breeds contribute considerably to beef production in subtropical regions of the U.S. Grandsire breed effects can be optimized by selection and use of appropriate crossbreeding systems.
Technical Abstract: The objective of this study was to characterize breeds representing diverse biological types for postweaning growth and carcass composition traits in terminal crossbred cattle. Postweaning growth and carcass traits were analyzed on 464 steers and 439 heifers obtained by mating F1 cows to Charolais and MARC III (¼ Hereford, ¼ Angus, ¼ Pinzgauer, and ¼ Red Poll) sires. The F1 cows were obtained from mating Angus and MARC III dams to Hereford, Angus, Beefmaster, Brangus, Bonsmara, and Romosinuano sires. Traits evaluated were postweaning ADG, slaughter weight, HCW, dressing percentage, percentage of carcasses classified as USDA Choice, LM area, marbling score, USDA yield grade, fat thickness, retail product yield (percentage), and retail product weight. Maternal grandsire breed was significant (P < 0.05) for all traits. Animals with Angus grandsires grew faster, had the heaviest carcasses, with the greatest percentage of carcasses classified as USDA Choice and the greatest marbling scores, when compared with other grandsire breeds. Animals with Romosinuano and Bonsmara inheritance grew slower, had the lightest weights at slaughter, the lightest carcass weights, the least percentage of carcasses classified as USDA Choice, and the least amount of marbling and fat thickness. Animals with inheritance from these 2 breeds had a more desirable yield grade with the greatest retail product yield. Maternal granddam breed was significant (P < 0.05) for marbling score, USDA yield grade, fat thickness and retail product yield. Sex class was significant (P < 0.05) for all traits except for retail product yield. Steers grew faster, were heavier, had heavier carcasses, and were leaner than heifers. Heifers had a greater dressing percentage, a greater percentage of carcasses classified as USDA Choice, a greater LM area, and a decreased yield grade when compared with steers. Sire and grandsire breed effects can be optimized by selection and use of appropriate crossbreeding systems.