Produção, qualidade, estabilidade oxidativa do leite e parâmetros nutricionais de vacas suplementadas com grãos de soja peletizados e monensina

Abstract

This study aimed to evaluate the pelleting effect of concentrated based on corn and soybean ground and monensin sodium on nutritional and metabolic parameters and on production, composition, fatty acid profile and oxidative stability of milk from Holstein cows. A total of twelve Holstein cows, multiparous, with an average weight ± standard deviation of 549.2 ± 84.8 kg, were distributed in a triple Latin square design with four experimental periods of 21 days each. The diets were: concentrated based on grinded soybeans and corn (GS); pelleted (GSP); grinded with monensina (GSM) and pelleted with monensina (GSPM). Diets did not affect DM intake, however, the apparent digestibility of CP and EE were significantly higher for pelleted diets and for the interaction between monensin and pelletizing. The NDF digestibility was significantly reduced in the pelleted diets. Different diets did not change statistically blood parameters. Ruminal parameters were unaffected by the diets, except for the ratio C2: C3 lower for treatments GSP and GSPM and for the interaction between monensin and pelletizing. There was no difference (P> 0.05) for milk production corrected for 3.5% of fat, protein and lactose, however, a significant reduction in fat and total solids for pelleted diets were observed. Urea concentration was significantly high for pelleted diet, aswell as for monensin and the interaction between them. Pelleted diets increased C10:0, C18:3 and C20:0 n3 and decrease C14:0; C14:1; C20:3 n6 and C20:5 n3 content. Furthermore, the interaction between monensin and pelletizing resulted in significant decrease of C14:0, C16:0 and C20:3 n6. Concentrations and ratios of fatty acids remained unchanged. The content of polyphenol, flavonoids and power reducing of milk was not significant (P> 0.05). The variable analyzed for diene conjugates, which measures the oxidative activity of Milk, was positively affected by pelleted diets.