Dry matter loss and nutritional composition of wet brewers grains ensiled with or without covering and with or without soybean hulls and propionic acid

The present study evaluated the variation on nutritional composition of wet brewers grains mixed with soybean hulls or propionic acid and stored from 7 to 63 d. On d 0, treatments were randomly assigned to buckets (24 buckets per treatment) and consisted of wet brewers grains with no addition (NOADD) and added with soy hulls at 15 or 30% of DM (15SH and 30SH) and propionic acid at 0.40% of wet weight (PROP). Effects of mixture × time were detected (P ≤ 0.05) for total DM loss and mean pH. Total DM loss of 15SH and 30SH was greater (P ≤ 0.01) or did not differ (P ≥ 0.48) compared with NOADD, whereas PROP tended (P ≤ 0.09) to lessen total DM loss. Effects of mixture × time were detected (P ≤ 0.0004) for concentrations of TDN, CP, ADF, NDF, and crude fat of nonspoiled DM material. Regardless of treatment, concentrations of TDN, ADF, NDF, CP and crude fat of nonspoiled DM mixture increased with storage days. Effects of mixture × time were detected (P ≤ 0.02) for concentrations of macro and trace minerals. Regardless of treatment, concentrations of Ca, P, Mg, Na, and K decreased, whereas concentrations of S, Cu, Fe, and Zn increased as storage time increased. Overall, adding soy hulls at 15 or 30% of DM resulted in the greatest total DM loss and variation on nutrient composition, whereas adding propionic acid at 0.40% of wet brewers grains wet weight resulted in least DM loss and effect on nutritional composition.