Effects of different cutting frequency and additives on silagequality and fermentation characteristics of mixed alfalfa

The purpose of the experiment was to explore the effects of different additives and cutting frequencies on the silage quality of mixed alfalfa. The two alfalfa varieties, ‘Golden queen’ and ‘3010’, mixed in the proportion of 4 ꞉ 1 cutting at different times were used as experimental materials, and five different additives ‘Sila-Max, Sila-Mix, Yaxin-Bio, Baiaomin, Taiwan Xiandeli’ were selected for use in a barrel silage test. Silage made without additives was used as the control (CK). After 60 days, the silage barrels were opened for laboratory evaluation. The results showed that as cutting times increased, the content of silage pH and dry matter (DM) also increased (P < 0.05). Crude protein, lactic acid (LA), and acetic acid (AA) increased at first but then decreased with increased cutting time. The content of acid detergent fiber (ADF), neutral detergent fiber (NDF), and crude ash (Ash) were lowest and water soluble carbohydrates (WSC) and monosaccharides (ESC) highest at the third cutting. Additives also had very significant effects on the contents of soluble protein as a proportion of total protein (SP/CP), DM, ESC (P < 0.01), and other indexes (P < 0.05). The CP, WSC, P, and K contents of the first cutting increased by 1.00%, 32.94%, 2.44%, and 0.99%, respectively, compared to CK, and the LA and AA contents of each cutting were higher than that of any other additives treated with Yaxin-Bio. The CP, SP/CP, and WSC contents of the third cutting increased by 1.37%, 6.39%, and 10.72%, respectively, compared to CK under the treatment of Baiaomin, which also had certain promoting effects on CP, SP/CP, and WSC. Taiwan Xiandeli promoted the increase of neutral detergent insoluble protein (NDIP) and acid detergent insoluble protein (ADIP) (P < 0.05), while Sila-Max and Sila-Mix had no obvious effects on nutrient quality (P > 0.05). In total, according to gray correlation analysis, the quality of MIXed alfalfa silage at the second cutting showed the highest quality, especially when treated with Yaxin-Bio, which could be used in the production practice of alfalfa silage.