Dynamic changes in the quality and microorganisms present in whole-plant corn silage under aerobic exposure

It is critical to enhance the feeding value of whole-plant corn silage, which is a type of high-quality roughage used in the animal husbandry industry. This study explored the changes in the quality and bacterial flora dynamics of whole-plant corn silage under aerobic exposure in a karst region to provide reference for its rational utilization. Whole-plant corn from Guanling and Weining were fermented for 45 days and then unsealed. The aerobic stability, nutrient composition, fermentation quality, and microbial structure of the two groups were analyzed after aerobic exposure for 0, 2, and 5 days. The results showed significantly decreased dry matter, crude protein, soluble carbohydrate, starch, neutral detergent fiber, acid detergent fiber, lactic acid, and acetic acid content in both groups with increasing aerobic exposure (P < 0.05). The pH and propionic acid and ammonia nitrogen contents in both groups increased significantly with increasing aerobic exposure (P < 0.05). Butyric acid was not detected in either group. The numbers of operational taxonomic units (OTUs) in the two groups significantly lower after aerobic exposure for 5 days compared to those at 0 days (P < 0.05). The Chao, abundance-based coverage estimator (ACE), Shannon, and Simpson values in the Guanling group were significantly lower after 5 days than at 0 day (P < 0.05) but did not differ in the Weining group (P > 0.05). The dominant floras at the phylum and genus levels of the two groups after 5 days of aerobic exposure were Proteobacteria and Acetobacter, respectively. In conclusion, the quality, bacterial abundance, and bacterial diversity of whole-plant corn silage in the two groups showed decreasing trends during aerobic exposure. These findings suggest that whole-plant corn silage on the surface should be fed within 2 days in warm and humid environments.