Evaluation of Production Systems for Progeny of Beef Sires with Higher Marbling Expected Progeny Differences

Two experiments evaluated higher-marbling, expected progeny difference (EPD) Angus sires on progeny growth, carcass traits, and meat composition. In trial 1, 40 progeny of sires with either high or low EPD for marbling were evaluated for feedlot performance, disposition score, carcass traits, palatability, and fat composition. Half of the cattle in each marbling group were harvested at an estimated 1.0cm s.c. fat, and the remainder were harvested at an estimated 1.5cm s.c. fat. In trial 2, 20 steers from high-marbling EPD sires were assigned to 1 of 4 treatments prior to entering a feedlot: 1) weaned at 170 d of age and backgrounded for 40 d; 2) weaned at 170 d of age; 3) weaned at 212 d of age and backgrounded for 40 d; or 4) weaned at 212 d of age. All steers were harvested at an estimated 1.25cm s.c. fat. In trial 1, marbling score was significantly different for sire group. Percentage USDA choice carcasses and YG were different for sire and harvest groups (P < 0.05). Final BW, ADG, feed efficiency, disposition score, meat lipid composition, Warner-Bratzler shear value, and consumer scores were not affected by sire group, endpoint, or sex. Early-weaning resulted in reduced marbling scores (P < 0.05) with no difference in other carcass or growth traits in trial 2. Backgrounding across weaning methods resulted in increased marbling score (P < 0.05) with no differences for other carcass and growth traits. Higher genetic potential for marbling may require a strategic weaning and feeding program to optimize carcass quality and yield.