The Effects of Corn Coproduct Supplementation on Primiparous Cow Reproduction and Calf Performance1

An experiment was replicated over 2 yr to determine the effect of additional RUP and dietary fat from dried distillers grains plus solubles (DDGS; n = 2) or wet corn gluten feed (WCGF; n = 2) before breeding on primiparous cow reproduction and calf production. Over 2 yr, 134 postpartum, primiparous cows (429 ± 5 kg initial BW) were fed 1 of 2 isocaloric, approximately isonitrogenous diets in 1 pen/yr (n = 4) providing varying levels of RUP and dietary fat. Treatments were initiated 21 (yr 1) and 60 d (yr 2) postpartum and continued for 56 (yr 1) or 16 d (yr 2) until timed AI. Diet type did not affect (P = 0.78) prebreeding BW; however, WCGF-fed cows had a greater (P = 0.03) ADG before breeding compared with DDGS-fed cows. Percentage of cows resuming estrus, becoming pregnant to AI, and becoming pregnant after bull exposure were similar (P > 0.10) between treatments. Male calf weaning BW, adjusted 205-d BW, and calf value were similar (P > 0.10) between treatments. Female calf weaning BW and calf value were also not different (P > 0.10) between treatments. Female calves from DDGS-fed cows tended to have a greater (P = 0.07) adjusted 205-d BW than calves from WCGF dams. In conclusion, WCGF in postpartum, primiparous beef cow diets improved cow ADG before breeding, and DDGS increased 205-d weaning BW of female offspring. Both DDGS and WCGF are acceptable supplements for primiparous cows and may improve beef production sustainability.