Ensiling characteristics and utilization of switchgrass preserved as silage

Abstract

Abstract Switchgrass ( Panicum virgatum L.) harvested at several maturities was readily ensiled when either directly cut and stored at a dry matter (DM) concentration of about 250 g kg −1 or wilted and stored at a DM concentration of about 350 g kg −1 . Silage pH ranged from 4.6 to 5.1 for all treatments with acetic and lactic acids predominating. Acetic acid concentrations in the direct cut silage was double the concentrations in the wilted silage while lactic acid concentrations were similar. Forage at ensiling was high in cell walls (694 to 743 g kg −1 ) and low in crude protein (53 to 63 g kg −1 ). Silage was stable when either direct cut or wilted and well preserved when air was excluded. Forage artificially-dried (hay) or when ensiled (direct cut or wilted) did not alter DM intake (kg 100 −1 kg body weight) which averaged 1.48 for the late boot stage and 1.41 when fully mature. Apparent digestion coefficients for DM and cell wall constituents of fully headed switchgrass showed no difference when preserved as hay or silage. Digestion coefficients from wilted silage were lower, however, than from direct cut silage for DM, crude protein, neutral detergent fiber, acid detergent fiber and cellulose. These results indicate that switchgrass can be preserved through fermentation with best results from immediate ensiling and subsequently utilized as silage in animal production systems.