Strategic timing of distillers grains supplementation for growing cattle grazing smooth bromegrass pastures1

Two experiments evaluated different strategies for supplementing growing cattle grazing smooth bromegrass (Bromus inermis) pastures with dried distillers grains plus solubles (DDGS). Exp. 1 used 55 yearling steers in each of 2 yr to compare cattle stocked at 6.8 animal-unit-months (AUM)/ha receiving no supplement to cattle receiving 0.6% of BW in DDGS daily and stocked at 9.9 AUM/ha. A third treatment also stocked steers at 9.9 AUM/ha and provided increasing amounts of DDGS as forage quality declined over the grazing season. Both supplementation strategies resulted in the same amount of DDGS fed over the entire grazing season. Exp. 2 used 36 steer calves in each of 5 yr to compare cattle stocked at 8.3 AUM/ha grazing smooth bromegrass pastures and receiving no supplement to cattle receiving DDGS at 0.5% of BW daily or cattle receiving no supplement the first 56 d of the experiment after which they were supplemented at 0.5% of BW daily. Cattle in Exp. 2 were followed through a finishing period with all cattle on a similar diet and the same number of days on feed. In both experiments, supplementing cattle with DDGS improved ADG (P < 0.01), regardless of supplementation amount. Delaying supplementation for the first 56 d did not decrease gains (Exp. 2; P ≥ 0.30), and increasing supplement amounts as forage quality declined did not improve gains (Exp. 1; P ≥ 0.17). Cattle supplemented with DDGS had greater HCW than nonsupplemented cattle (Exp. 2; P < 0.01).