Effect of Energy Supplementation of Stocker Cattle Grazing Smooth Bromegrass Pastures on Grazing and Subsequent Finishing Performance and Carcass Traits1

Grazing and subsequent finishing performance of 117 Angus stocker calves (Bos taurus; BW = 235.5 ± 1.22 kg) supplemented with 0, 0.82, or 1.64 kg/d of grain sorghum (Sorghum bicolor) on a DM basis while grazing smooth bromegrass (Bromus inermis) pastures in 2002, 2003, and 2004 were evaluated. Cattle continuously grazed pastures at a stocking rate of 2 steers/ha from mid-April to early November of each year and were then finished for slaughter and collection of carcass data. Supplementation with 0.82 or 1.64 kg/d of grain sorghum resulted in 11.2% greater (P < 0.05) or 20.4% greater (P < 0.05) grazing ADG, respectively, than feeding no supplement. Energy supplementation during the grazing phase had no effect (P > 0.05) on forage mass, finishing ADG, or DMI during the finishing phase. Cattle supplemented during the grazing phase maintained their weight advantage through the finishing phase, were heavier (P < 0.05) at slaughter, yielded heavier (P < 0.05) carcasses, and had greater (P < 0.05) overall ADG than those that received no supplement. Cattle supplemented with 0.82 kg/d of grain sorghum required less (P < 0.05) feed per unit of gain during the finishing phase than those that were previously supplemented with 1.64 kg/d. Supplementation with 1.64 kg/d of grain sorghum during the grazing phase resulted in a greater (P < 0.05) marbling score than feeding no grazing supplement. Overall ADG from the beginning of the grazing phase through the end of the finishing phase was greater (P < 0.05) for cattle that were supplemented with grain sorghum while grazing.