Biological and economic performance of early-weaned Angus steers

Over 2 yr, 45 Angus-sired steer offspring of Angus and Angus crossbred fema les were used to determine the effects of early weaning on feedlot performa nce, carcass characteristics, and economic return to the cow-calf enterpris e. Steers were assigned by birth date to one of two weaning treatments: 1) weaned at an average age of 100 d (early weaned) or 2) weaned at an average age of 200 d (normally weaned). Within 36 d of weaning, steers were given ad libitum access to a high-concentrate diet (90% dry, whole-shelled corn). Steers were harvested when 12th-rib fat thickness averaged 1.27 cm within treatment as estimated by ultrasound. Carcass measurements were taken 48 h postmortem and rib steak tenderness was determined at 14 d postmortem by Wa rner-Bratzler shear force. Early-weaned steers had greater ADG from time of early weaning to normal weaning than suckling normally weaned steers (1.27 vs 0.86 kg/d, respectively; P < 0.001). However, early-weaned steers tende d to have lower ADG for the entire finishing period than did normally weane d steers (1.33 vs 1.39 kg/d, respectively; P = 0.08). Compared with normall y weaned steers, early-weaned steers had lower daily DMI (7.40 vs 5.95 kg/d , respectively; P < 0.001) and lower total DMI for the finishing period (1, 618 vs 1,537 kg, respectively; P < 0.05). Early-weaned steers had greater g ain:feed for the finishing period than normally weaned steers (0.223 vs 0.1 89, respectively; P < 0.001). Carcass weights were lighter for early-weaned steers than for normally weaned steers (277.9 vs 311.2 kg, respectively; P < 0.001). There was no difference in yield grade (3.1 vs 3.2; P < 0.10) be tween treatments. All carcasses graded Low-Choice or greater, and there was no difference in the percentage of carcasses grading Mid-Choice or greater (94.5 vs 83.9% for early- and normally-weaned, respectively; P > 0.10). Wa rner-Bratzler shear force values were similar between treatments. Early-wea ned steers had a lower cost of gain than normally weaned steers ($ 0.82 vs 0.91/kg, respectively; P < 0.001). However, due to lighter carcass weights, early-weaned steers generated less return to the cow-calf enterprise than normally weaned steers ($ 380.89 vs 480.08/steer; P < 0.001). The early wea ning of steers at 100 d of age decreased total DMI, improved gain:feed, and lowered the cost of gain; however, return to the cow-calf enterprise was d ecreased due to lighter carcass weights.