Bagaço de cana-de-açúcar como volumoso exclusivo para vacas em lactação

Abstract

Sugarcane bagasse is a food that is widely used in ruminant feeding, but there are few studies that use this ingredient as exclusive roughage for the dairy cattle. However, the objective of this study was to evaluate intakes of dry matter and nutrients, intake behavior, milk production, microbial protein synthesis, fatty acid profile and nutritional quality indexes of milk fat of cows fed sugarcane bagasse as exclusive roughage. Ten lactating Girolando cows were distributed into a 5 × 5 double Latin squares design and fed five different diets: four increasing levels of sugarcane bagasse [30, 38, 46, and 54% of dry matter (DM)] and the control diet, based on spineless cactus, sugarcane bagasse, and concentrate. The DM intake and digestibility decreased linearly with sugarcane bagasse increasing levels. The time spent with rumination was higher for cows fed 54% sugarcane bagasse level in the diet. There was no effect of sugarcane bagasse levels on the efficiency of microbial protein synthesis. The 54% sugarcane and control diets provided a higher concentration of CLA cis-9 trans-11. The atherogenicity and the thrombogenicity index showed quadratic behavior; and the Omega 6:Omega 3 and hypo:hypercholesterolemic fatty acids ratios decreased linearly with sugarcane bagasse inclusion. In conclusion, the sugarcane bagasse inclusion in diets of crossbred dairy cows decreases milk production. However, sugarcane bagasse can be used associated to concentrate feed, being the level of inclusion dependent on expected performance. The utilization of diets with 30% sugarcane bagasse and 70% concentrate indicates the potential for production of milk with a better quality fat.