The use of crude glycerin as an alternative to reduce fermentation losses and enhance the nutritional value of Piatã grass silage

ABSTRACT The objective of this study was to evaluate fermentation losses and the nutritional value of silage of Brachiaria brizantha cv BRS Piatã ensiled with different levels of crude glycerin. The experiment followed a 4 × 2 completely randomized factorial design with four doses of crude glycerin (0, 100, 200, and 300 g kg–1 of DM silage) and two cutting ages (45 and 60 days) with four replicates per treatment (silos). The parameters of dry matter losses, effluents losses, gas losses, pH, microbial population, and nutritional value of the silage were evaluated. There was no difference in pH among the tested doses of crude glycerin. However, reductions in dry matter and gas losses were observed as a function of crude glycerin doses. Bacterial populations of lactic acid and facultative mesophilic anaerobes also increased as a function of crude glycerin inclusion. Crude glycerin increased ether extract levels and reduced neutral detergent fiber and acid detergent fiber concentrations (dilution effect), improving chemical composition of the silage. Crude glycerin can be used in the ensiling of Piatã grass and the dose of 300 g kg–1 of DM yields the best results.