Effects of different silage additives on the nutritional quality and fermentation characteristics of mixed alfalfa

In this study, the effects of different silage additives (Sila-MAX, Sila-MIX, Yaxin Bio, Baiaoming, and Taiwan Freshli) on the nutritional quality and fermentation characteristics of mixed alfalfa were explored, without the use of a control additive. The nutritional qualities dry matter (DM), crude protein (CP), neutral detergent fiber (ADF), acid detergent fiber (ADF), and total digestible nutrients (TDN) and fermentation characteristics ammoniacal nitrogen/total nitrogen (NH₃-N/TN), pH, lactic acid (LA), and acetic acid (AA) of the samples placed in aerobic storage for 0, 24, 48, and 72 h after 60 fermentation days were determined. The results showed that the nutritional quality and fermentation characteristics of silage alfalfa changed after 0, 24, 48, and 72 h of aerobic storage. Compared with the control, the DM and TDN contents increased significantly under the Sila-MIX and Yaxin Bio treatments (P < 0.05). The DM content of each treatment increased with the prolongation of aerobic storage, while the TDN content only increased under the Sila-MIX treatment (P < 0.05). The CP content of each treatment was lower than that of the control, especially for 48 and 72 h of Sila-MIX treatment, which decreased by 2.38% and 2.03%, respectively. After 0, 24, 48, and 72 h of aerobic storage, the LA content of silage alfalfa under each treatment increased with the increase in storage time, but no significant differences were found (P > 0.05). There were no significant differences regarding the pH between treatments (P > 0.05). Compared with the control, the NH₃-N/TN content decreased after 0, 48, and 72 h of aerobic treatment (P > 0.05), showing an obvious reduction under the Sila-Mix and Yaxin Bio treatments. Grey correlation analysis showed that the quality of alfalfa silage treated with different additives was as follows: Yaxin Bio > Sila-Mix > Baiaoming > Sila-Max > Taiwan Freshli. Therefore, Yaxin Bio and Sila-Mix are suitable additives for alfalfa silage and could be popularized and applied in production practice.