Effects of stocker-phase grazing system and implantation on performance and carcass characteristics of fall-born steers

Fall-born Angus and Angus × Hereford steers (n = 113; BW = 226 ± 4.5 kg) were used in a 2-yr study evaluating the effects of growth-promoting implants and grazing system during the stocker phase on performance and carcass traits. Steers were assigned to 1 of 4 treatment combinations arranged in a 2 × 2 factorial design. Grazing treatments included 1) late-season grazing of tallgrass native range with protein supplementation from June to December (FG) and 2) FG followed by wheat-pasture grazing from December to March (WP). Implant treatments included 1) stocker-phase implant of Component TE-G (Elanco Animal Health, Greenfield, IN) administered at weaning and 2) no stocker-phase implant (control). Compared with FG, WP increased final BW, finishing-phase ADG, HCW, and rib-eye area (P < 0.02). Grazing-phase implantation increased ADG and final grazing BW during both the fall grazing and wheat pasture periods (P < 0.05). However, grazing system did not influence marbling score or YG (P > 0.13). Carcass weight, DP, fat thickness, and YG were not influenced by grazing-phase implant, although the percentage of cattle grading in the upper 2/3 of the Choice QG was reduced (P < 0.01). Extending the grazing season by using winter-wheat pasture may increase carcass weight without compromising carcass quality. Grazing-phase implantation of cattle increases performance during grazing, although the percentage of cattle grading in the upper 2/3 of the Choice QG may be reduced.