Quality of re-ensiled sorghum silages after prolonged periods of environmental exposure

Abstract

The aim of this study was to evaluate the effect of re-ensiling on the fermentability coefficient (FC), chemical composition and fermentation profile of untreated whole-crop sorghum silage after prolonged periods of environmental exposure. Treatments comprised eight times of exposure to the environment (0, 6, 12, 24, 48, 72, 96, and 120 h) and two procedures for conservation (conventional and re-ensiling) in a completely randomized design with two factors and three replicates. Experimental silos made of 12-L plastic buckets were used in trials. Silage nutritive value, fermentation profile, and dry mass (DM) losses were analyzed before and 90 days after re-ensiling. Regression analyses were performed, and ANOVA was used to compare means. The FC was higher than 45 even when the silage was exposed to air for 120 h before re-ensiling (59.2±2.54). Regression equations were fitted to the data with low accuracy (R2 < 0.47). Moreover, we observed that the main effect occurred between before and after re-ensiling, decreasing the contents of DM (42 to 37 %) and water-soluble carbohydrates (7.0 to 5.8 % DM), neutral detergent fiber (60.4 to 55.4 % DM), and acid detergent fiber (49.5 to 33.5 % DM), but increasing those of lactic acid (0.52 to 0.96 % DM) and ammoniacal nitrogen (1.58 to 2.51 % total N). The DM losses were linear with increasing times of air exposure; however, silage nutritive value and fermentation profile showed no disturbing changes for silage conservation and animal feeding.