Effects of increasing levels of distillers grains in barley-based diets on growing and finishing feedlot performance, carcass traits, and nutrients in manure

Two feedlot trials evaluated increasing levels (0, 12, 24, and 36% DM basis) of dried distillers grains plus solubles (DDGS) in barley-based diets. The DDGS replaced barley and canola meal in both trials. In the growing trial, diets (121 Mcal/kg NEg) were fed to 162 weaned steers (initial weight 284.9 ± 4.41 kg) for 56 d, with 4 pens per treatment. The DMI increased with any level of DDGS (P = 0.07), as did gains (P ≤ 0.01). Feed efficiency was not affected (P = 0.63). Nitrogen in manure increased with DDGS level. The finishing diets (137 Mcal/kg NEg) were fed to 131 yearling steers (initial weight 444.44 ± 6.57 kg) for 90 d before market in 4 pens per treatment. Intake tended to show a positive linear response (P = 0.09) to level of DDGS. Gains were greater (P ≤ 0.01) with DDGS in the diet and improved linearly (P ≤ 0.01) as DDGS increased. Carcass traits reflected increased gain with linear increases in dressing percentage (P ≤ 0.01), fat thickness (P ≤ 0.01), marbling scores (P = 0.02), YG (P < 0.01), and internal fat (KPH, P ≤ 0.01). The percentage of USDA Choice carcasses was 31, 53, 66, and 69%, respectively, for the 0, 12, 24, and 36% DDGS treatments. Performance improved for growing steers fed barley with DDGS at any inclusion level. During finishing, DDGS fed at 24% provided optimum performance and carcass traits for yearling cattle.