Silages processed with gramineous grass and wood feed mixtures may have positive associative effects on silage quality and animal performance when ruminants are fed those silages. The present study was conducted to evaluate the fermentation quality, chemical composition, and in vitro rumen digestion characteristics of silages produced with mixtures of sweet sorghum (SS) and korshinsk pea shrub (KP) in six different ratios of fresh weights: 100:0 (0%KP), 80:20 (20%KP), 60:40 (40%KP), 40:60 (60%KP), 20:80 (80%KP), and 0:100 (100%KP). As the proportion of KP increased in the silages, the contents of lactic acid, acetic acid, starch, total phenolics, hydrolysable tannins, and condensed tannins decreased (p < 0.05), while the pH value and the contents of neutral detergent fiber, acid detergent fiber, ether extract, crude protein, and ash increased (p < 0.05). The silages were evaluated in 48 h incubations with rumen liquor. The in vitro dry matter digestibility, in vitro neutral detergent fiber digestibility, and in vitro gas production decreased as the proportion of KP increased (p < 0.05). This study suggests that ensiling SS-KP at a ratio of 80:20 is a practical method for preserving such low-DM forages (SS) and that these silage mixtures offer an opportunity to optimize the nutrient supply for ruminant production.
Keywords: chemical composition; in vitro gas production; mixed silage; sweet sorghum; volatile fatty acids.
© 2022 Japanese Society of Animal Science.