Assessing Fermentation Quality, Aerobic Stability, In Vitro Digestibility, and Rumen Degradation Characteristics of Silages Mixed with Sweet Sorghum and Aerial Parts of Licorice

(1) Aim: This study aimed to evaluate the fermentation quality, chemical composition, aerobic stability, in vitro digestibility, and rumen degradation characteristics of silage mixtures with different ratios of sweet sorghum (SS) and aerial parts of licorice (LC). (2) Methods: Five mixtures were produced on a dry matter (DM) basis: (i) 0%SS + 100%LC (0%SS); (ii) 25%SS + 75%LC (25%SS); (iii) 50%SS + 50%LC (50%SS); (iv) 75%SS + 25%LC (75%SS); and (v) 100%SS + 0%LC (100%SS). First, the chemical composition of the silages was measured before and after fermentation. Next, the aerobic stability, dynamic microbial colonization and dynamic volatile fatty acids of the mixed silage after fermentation were determined for 0, 5, 10, 15, 20, and 25 days. Finally, the parameters related to gas production and the characteristics of the gas production were determined. At the same time, the rate of degradation of the chemical composition of the mixed silage in the rumen was studied. (3) Results: (a) As the proportion of SS increased, pH, ammonia, butyric acid, acetate, and aerobic stability showed a decreasing trend, but lactic acid content gradually increased. (b) The content of the fermentation and gas production parameters were significantly higher in 100%SS and 50%SS than others ( p < 0.05). (c) The rate of degradation of DE, ME, Neg, DM, CP, ADF, NDF, and ADL of 50%SS in the rumen of sheep was significantly higher than others ( p < 0.05). (4) Conclusions: In conclusion, ensiling SS and LC mixtures can improve silage quality, especially if the SS and LC are ensiled together at a ratio of 50:50.