Effect of additives on the quality of ryegrass silage with different dry matter content

The effects of different types of inocula on the quality of Italian ryegrass with different dry matter content were investigated. Three additives formic acid (FA), Lactobacillus plantmentum (LP), Lactobacillus buchneri (LB) were used to ensile Italian ryegrass with different dry matter content (20%, 30%, and 40%). The results showed that the pH in the FA-treatment of Italian ryegrass with three levels of dry matter content was below 4.3, and NH3-N/TN was significantly lower than that in the other treatments (P<0.05). However, the content of water soluble carbohydrate was significantly higher than that in the other treatments (P<0.05). Two types of lactic acid bacteria treatments (LP and LB) of Italian ryegrass with dry matter content of 30% and 40% led to better ferment quality. The lactic acid content in the LP treatment was significantly higher than that in the other treatments (P<0.05), whereas the acetic acid content of the LB treatment was significantly higher than that in the other treatments (P<0.05). The ferment quality of Italian ryegrass with 30% and 40% dry matter content was better than that of 20% dry matter content in treatments with the same additive. Particularly, when the dry matter content was 40%, the pH of the control group was less than 4.2, which suggested that at this level of dry matter content, high quality silage can be prepared even without adding any additives. Evidently, wilting Italian ryegrass with a dry matter content of 30%40% treated with lactic acid bacteria can ensure high quality silage production. In unwilted Italian ryegrass, adding formic acid (4 mL·kg-1 FM) can preserve silage quality.