Treatment of alfalfa silage with tannin acid at different levels modulates ensiling characteristics, methane mitigation, ruminal fermentation patterns and microbiota

Abstract The objective of this study was to evaluate the potential of tannin acid (TA) derived from Chinese gallnut, with different doses for modulating ensiling characteristics, methane (CH4) emission, ruminal fermentation profile and microbiota of alfalfa silage. Second-cut alfalfa was wilted for 6 h to dry matter (DM) 439 g/kg fresh weight and chopped to 2 cm length. The chopped forage was ensiled with 5 TA levels (0, 10, 20, 40, and 60 g/kg DM), and each treatment was ensiled in triplicate in vacuum-sealed polyethylene plastic bags for 60 d. All TA treatments improved the fermentation quality of alfalfa silage, indicated by lower (P