Assessing the Fermentation Quality, Bacterial Composition and Ruminal Degradability of Caragana korshinskii Ensiled with Oat Grass

The purpose of this study was to explore the effects of co-ensiling Caragana korshinskii with different proportions of oat grass on silage fermentation quality, chemical composition, in situ rumen degradability and in vitro rumen fermentation characteristics. C. korshinskii and oat grass were mixed at different ratios of 100:00, 90:1, 80:2, 70:30, 60:40 and 50:50. Each ratio of mixture was ensiled for 7, 14, 30, 45 and 60 days at room temperature (25 °C), with 30 bags per ratio, for a total of 180 bags. We further investigated the dynamic profiles of the bacterial community during ensiling and in vitro rumen fermentation. The results showed that co-ensiling C. korshinskii and oat grass decreased the pH values and increased the content of lactic acid and acetic acid compared with ensiling C. korshinskii alone. C. korshinskii ensiled with oat grass at a ratio of 70:30 (70% C. korshinskii) showed the best fermentation quality, which was related to higher relative abundance of Lactobacillus and Weissella. The silage with the ratio of 70:30 (70% C. korshinskii) showed higher dry matter digestibility and the more production of gas and total volatile fatty acids, compared with fresh C. korshinskii. In conclusion, C. korshinskii co-ensiled with oat grass at a ratio of 70:30 could enhance the fermentation quality and digestibility of C. korshinskii.