Limit feeding high-energy, by-product-based diets to late-gestation beef cows in confinement

Three experiments using late-gestation, multiparous beef cows (total n = 175; BW = 534 kg; BCS = 5.6) were conducted to determine the efficacy of limit feeding (less than 2.0% of BW) diets consisting of by-products from the sugar and ethanol industries and crop residues to maintain gestating beef cows in confinement. In Exp. 1, no differences in BW, BCS, or calf birth weight were determined (P ≥ 0.53) comparing a blend of wet distillers grains and wheat straw (30:70 ratio, DM basis; DG/STW) with alfalfa hay when fed 8.3 and 9.1 kg of DM, respectively. In Exp. 2, wet distillers grains, sugar beet pulp, and wheat straw (20:20:60 ratio DM basis; 20 PLP) were compared with DG/STW and AH. Cows were fed 8.5 kg/d DG/STW and 20 PLP and 7.8 kg/d AH. Cows fed alfalfa hay gained less BW (30 kg) than cows fed DG/STW and 20 PLP (66.8 and 73.6 kg, respectively; P < 0.0001). Cows fed alfalfa hay also had lower BCS (5.3) compared with cows fed DG/STW and 20 PLP (5.7 and 5.8, respectively; P < 0.0001). Calf birth weight was not different among treatments (P = 0.12). In Exp. 3, cows were fed 8.5 kg 20 PLP compared with 7.0 kg wet distillers grains, sugar beet pulp, and wheat straw (20:45:35 ratio, DM basis; 45 PLP). Calf BW, cow BW, and BCS were not different between treatments (P ≥ 0.39). Crop residues and by-products can be limit fed to gestating beef cows as an alternative to ad libitum hay or forage while maintaining performance.