Meta-analysis of the effects of silage additives on high-moisture grain silage quality and performance of dairy cows

Abstract Our objective was to evaluate the effects of applying silage additives to high moisture grain silage (HMGS) on its quality (objective 1) and performance of dairy cows (objective 2). Additionally, this study aimed to investigate the effects of replacing dry grain (DG) with HMGS on performance of lactating dairy cows (objective 3). Silage quality (dataset composed by 8 studies with 32 treatment means), was evaluated by weighted means difference (WMD) between the control (HMGS with no silage additives) and treated-HMGS (HMGS treated with silage additives) groups. The effects of replacing DG with HMGS on performance of lactating dairy cows (dataset composed by 18 studies with 34 treatment means) was evaluated by WMD between the control group (diets with no HMGS) and HMGS group (diets with HMGS replacing DG). Treatment means were weighted by the inverse of the variance. Applying silage additives to HMGS had no effect on silage pH (P = 0.27), DM recovery (P = 0.18), ethanol (P = 0.18) and counts of yeasts (P = 0.86) and molds (P = 0.13). However, increased silage concentrations of N-NH3 (WMD = 0.49 g/kg of total nitrogen; P