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An Evaluation of six years of carcass and feedlot performance in Brahman and Brahman influenced steers tested by the American Brahman Breeders Association (ABBA) National Carcass Evaluation Program
The American Brahman association has made concerted efforts to improve the carcass quality and composition of Brahman and Brahman influenced cattle. Thus, the objective of the current study was to evaluate genetic trends for Brahman steer calves that have comprised six years (2004-2010) of the American Brahman Breeders Association (ABBA) National Carcass Evaluation Program. A total of 418 steers were evaluated for growth traits, and carcass quality and composition traits. Steers were fed in Gonzalez TX until a desirable harvest weight was achieved. Steers were then transported to a commercial harvest facility where carcass quality and composition traits were collected. Growth and performance traits collected in the feedlot that were evaluated in the current study consisted of entrance weight into the feedlot (INWT), harvest weight (HRVWT) and average daily gain (ADG). Carcass quality and composition traits that were evaluated included hot carcass weight (HCW), ribeye area (REA), marbling score (MARSC), yield grade (YG), dressing percent, and Warner-Bratzler shear force (WBS) analysis for meat tenderness evaluation. The PROC REG procedure of SAS was utilized to determine the average increase or decrease of performance for each trait over the six year evaluation period. Entrance weights into the feedlot in 2004 averaged 239.47 kg and HRVWT averaged 494.35 kg. Entrance weights and HRVWT in 2010 had increased to 292.11 kg and 579.26 kg respectively. Subsequently, all growth traits evaluated in the current study exhibited a linear increase over the six year evaluation period with INWT increasing 5.5 kg/year, HRVWT increasing 11.1 kg/year and average daily gain increasing 0.17 kg/year. When evaluating carcass quality and composition traits it was revealed that all traits with the exception of MARSC exhibited a linear increase. Marbling score was the only trait observed not to increase over the six year testing period, decreasing at a rate of 3.7 marbling score units per year respectively. The carcass traits that exhibited a linear increase over the six year evaluation period included HCW (7.2 kg/year), REA (0.55 cm/year), YG (0.04 units/year), WBS (0.41 kg/year) and dressing percentage (0.10/year).
Keywords: Bos Indicus, Genetic Trends, Carcass Traits