Effects of spoilage of wet distillers grains plus solubles when stored in a bunker on nutrient composition and performance of growing and finishing cattle1

Three experiments evaluated the effect of spoilage of wet distillers grains plus solubles (WDGS) on nutrient composition and cattle performance. In Exp. 1, a 140-d barrel storage study was conducted to simulate bunker storage. An interaction between days of storage and DM, OM, and NDF recovered at the surface in spoiled material was observed. In Exp. 2, a 130-d finishing experiment used 60 individually fed steers fed 3 treatments: a dry-rolled corn-based diet (control) and 2 diets containing 40% WDGS replacing dry-rolled corn. The WDGS was stored in either an uncovered bunker (spoiled) or anaerobically in a silo bag (non-spoiled). Calculations suggest 12% of DM was lost while stored in the bunker. No differences in performance (P ≥ 0.26) were observed between WDGS treatments. However, both WDGS treatments were greater (P ≤ 0.04) in ADG, final BW, and G:F than the dry-rolled-corn diet. In Exp. 3, an 84-d growing experiment used 60 individually fed steers in a 2 × 2 factorial. Treatments were spoiled versus nonspoiled WDGS fed at 15 or 40% (DM basis). Calculations suggest that 6.0% of DM was lost while stored in the bunker. Feeding spoiled WDGS decreased DMI (P < 0.01) across both levels of dietary WDGS compared with nonspoiled WDGS. Diets containing spoiled WDGS had similar ADG and G:F compared with diets with nonspoiled WDGS (P ≥ 0.16). Feeding WDGS containing spoilage did not affect performance of finishing steers. Spoilage did decrease DMI but had little effect on ADG and no effect on G:F when fed to growing steers.