Comparison of wet and dry distillers grains plus solubles to corn as an energy source in forage-based diets1

Four experiments compared wet or dry distillers grains plus solubles (WDGS or DDGS) to corn as energy sources in forage-based diets. In Exp. 1, 66 individually fed steers (268 kg of initial BW) were fed a 60:40 blend of sorghum silage and alfalfa hay and supplemented at 0, 0.33, 0.67, or 1.0% of BW with either WDGS or DDGS. In Exp. 2, 160 steers (286 kg of initial BW) were fed 25% WDGS or 33.6% dry rolled corn (DRC) in 35% sorghum silage and grass hay diets (DM basis). In Exp. 3, 60 individually fed steers (231 kg of initial BW) were fed DRC at 22.0, 41.0, or 60.0%, or WDGS at 15.0, 25.0, or 35.0% of diet DM in 30% sorghum silage and grass hay diets. In Exp. 4, 120 individually fed steers (282 kg of initial BW) were fed DDGS, WDGS (15 or 30% of diet DM), or DRC (22 or 50% of diet DM) in sorghum silage and grass hay diets. In Exp. 1, 3, and 4, increasing DGS inclusion increased ADG (P < 0.01) in forage-based diets. In Exp. 3, cattle consuming WDGS gained more BW than cattle fed DRC (P < 0.01). Using regression analysis, data from Exp. 2, 3, and 4 were pooled to calculate the energy value of WDGS relative to DRC in forage diets. The energy value of WDGS was 137% and 136% of DRC when fed at 15 and 30% of diet DM, respectively.