Effects of additives on fermentation quality and CNCPS protein fractions of legume–grass silage mixture

Medicago sativa and Bromus inermis with ratios of 1 ꞉ 2 and 2 ꞉ 2 legume–grass mixtures were used as material to study the effects of additives on fermentation quality and CNCPS protein fractions of mixed forage with different mixed sowing proportion. The control, Lactobacillus plantarum and Lactobacillus casei treatment were set, respectively. The LAB inoculant were applied at the rate of 1.0 × 10⁵ cfu·g⁻¹. The protein components and protease activities of the mixed forage were dynamically measured at 0, 1, 3, 7, 15, 30 and 60 d after silage. The fermentation quality, nutrient components, and nitrogen components were measured at 60 d after silage. The results have shown that the additives could reduce the non protein nitrogen, conjugated protein, carboxypeptidases activity, pH, and ammonia nitrogen. In contrast, it increased the lactic acid, therefore, improving the quality of the legume–grass silage mixture. The quality of the ratio of 1 ꞉ 2 legume–grass silage mixture was higher than that of 2 ꞉ 2 legume–grass silage mixtures. The ratio of 1 ꞉ 2 legume–grass silage mixture with Lactobacillus plantarum added had the highest fermentation quality with pH 3.74, lactic acid content of 85.3 g·kg⁻¹, and a DM and V-Score of 90.