Nutritional composition and ruminal degradability of corn silage (Zea mays L.) with addition of glycerin in silage Composição nutricional e degradabilidade ruminal da silagem de milho (Zea mays L.) com adição de glicerina na ensilagem

The objective was to study the corn silage with addition of 0, 5, 10, 15 and 20% glycerin, ensiled in experimental silos of PVC. At the opening of the silos there were evaluated the chemical composition, in vitro digestibility of dry matter (IVDDM) and cell wall (IVDCW) and aerobic stability through measures of temperature and pH of silage at 0, 24, 48, 72, 96 and 120 hours. In situ degradability of dry matter, crude protein and neutral detergent fiber of silages were evaluated in fistulated cattle using samples incubated at 0, 2, 4, 6, 12, 24, 48 and 96 hours. The experimental design was completely randomized design and statistical analyzes were performed using Bayesian inference. Increases were observed in DM, mineral matter (MM), non-fibrous carbohydrates (NFC) and reductions for neutral detergent fiber (NDF), acid detergent fiber (ADF), crude protein (CP) and ether extract (EE) as the inclusion of glycerin was higher. The content of total digestible nutrients (TDN) estimated in treatments with 5, 10, 15 and 20% glycerin, were superior to the control (P<0,05) range of 2.13, 8.95, 10.33 and 13.13% respectively. The temperature and pH of the silage with 10 and 15 and 20% glycerin remained lower than those levels (P<0.05) measured during silage and 20% glycerin showed high stability after 120hours. The IVDDM and IVDCW in corn silages with 15 and 20% were higher than the other (P<0,05). The effective degradability of DM fractions in passage rates of 2, 5 and 8% / h was better in silage with 15% and 20% glycerin. Glycerin has proved to be a great additive for corn silage being able to enrich the energy density, improving the degradability of DM and maintaining the aerobic stability of silage.