Effects of Optaflexx feeding on animal performance, carcass traits, yields of carcass primals and value cuts, and meat tenderness in ovariectomized heifers
Talton, Clayton Seaborne
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Forty-eight heifers, of predominantly British breeding, were used to investigate the effects of Ractopamine (RAC) supplementation and ovariectomization (OVX) on feedlot performance, carcass yield and quality traits, and subprimal and value-cut yields. Dressing percentage was higher (P < 0.01) in RAC-fed heifers than controls (CTL) and HCW, CCW, and REA tended (P < 0.10) to be increased by RAC feeding. Intact heifers had higher (P < 0.01) DP and larger (P = 0.05) REA and tended to have higher (P = 0.09) bone maturity scores and lower (P = 0.09) YG than OVX heifers. The ribeye roll, shoulder clod, and gooseneck round were heavier (P < 0.05) and the tenderloin and knuckle tended (P < 0.10) to be heavier in RAC-fed heifers compared to CTL. Conversely, OVX decreased (P = 0.04) the yield of the ribeye roll and tended (P = 0.06) to decrease the yields of the brisket and strip loin compared to INT heifers. The interaction of RAC supplementation and gender significantly affected the value cuts shoulder top and top blade weights. These value cut weights were higher (P < 0.05) with RAC feeding in INT heifers, while weights were similar in OVX heifers.