Carcass and meat quality traits in Brangus steers

The quality grade system used in the United States to identify carcasses with superior eating satisfaction to consumers is based on the amount of marbling within the ribeye and the maturity of the carcass. However, the most important quality attribute for consumers is tenderness. The objective of this study was to investigate the phenotypic correlations between carcass and meat quality traits of strip loin steaks from Brangus steers, particularly the relation between the United States Department of Agriculture (USDA) quality grade and tenderness. Warner-Bratzler shear force (WBSF) values in this study averaged 5.10 +/- 0.96 kg, slightly higher than the national average of 4.55 +/- 1.14 kg. Average WBSF across all quality grades ranged from 4.90 to 5.27 kg with standard deviations ranging from 0.78 to 1.40 kg. In the present Brangus steer population, there was a weak negative (-0.13) but favorable correlation (P < 0.05) between marbling score and tenderness measured through WBSF. The USDA quality grade had a significant (P = 0.02) effect on WBSF. The WBSF least square means were significantly higher in the Select compared with the Choice(-), and Choice(o) quality grades. The Choice(+) and Prime quality grades were not significantly different from any quality grades regarding the WBSF. The standard quality grade did not have significantly different WBSF least square means from any other quality grade. The range of WBSF values was large, especially in the lower quality grade categories, indicating that there is considerable variation in tenderness, even within quality grade. The high level of variation in tenderness within USDA quality grades highlights the limitation of the USDA grading system to predict eating quality or tenderness. Lay Summary The quality grade system used in the United States to identify carcasses with superior eating satisfaction to consumers is based on the amount of marbling within the ribeye and the maturity of the carcass. However, the most important meat quality attribute for consumers is tenderness. In the present study, tenderness varied considerably within quality grade, especially in the lower quality grade categories. Consequently, the United States Department of Agriculture quality grade system, which is intended to predict consumer satisfaction and palatability, may not be an accurate predictor of tenderness or consumer satisfaction. Inaccurate estimation of tenderness can lead to dissatisfied consumers, which could lead to nonrepeat customers and decreased beef demand, negatively impacting all sectors of the beef industry. Improving tenderness through traditional selection is difficult because tenderness has weak to no correlation with easily measured carcass and meat quality traits and collection of tenderness data on a routine basis is difficult and expensive. Genomic selection seems to be the most feasible approach to make significant genetic improvement.