Effects of Ensiling Duration on Fermentation Quality and Bacterial Communities of Fermented Total Mixed Ration Formulated with Corn Stalk and Broom Sorghum Straw

Fermented total mixed ration (FTMR) is an effective approach to preserve low-quality crop residues. This study investigated the effects of ensiling duration (0, 3, 5, 7, 15 and 30 days) on nutritional dynamics, fermentation quality, in vitro digestibility, and bacterial communities of FTMR containing corn stalk and broom sorghum straw at 50% moisture. After 30 d of ensiling, FTMR had the highest crude protein content, lowest neutral detergent fiber content, peak lactic acid concentration, stable low pH, undetectable butyric acid, and maximum in vitro NDF digestibility. Bacterial alpha diversity declined significantly during ensiling, and the community was dominated by Leuconostoc, Lactiplantibacillus, and Levilactobacillus. These results clarify the microbial regulatory mechanism of mixed-straw FTMR fermentation and support the efficient utilization of crop residues in ruminant production.