Enzimas fibrolíticas em dietas de novilhas leiteiras

Abstract

This work aims to evaluate the effect of the fibrolytic enzyme on the use of sugarcane silage and corn silage in ruminal and blood parameters, nutrient consumption and degradability with or without inclusion of fibrolytic enzyme in sugarcane silage and corn silage offered to the animals to establish the inclusion or not of this enzyme in the diet and its use with sugarcane silage or corn silage in the diet of dairy heifers. The experiment was conducted in the Animal Science sector of the Federal University of Grande Dourados (UFGD), with a total experimental period of 84 days. Eight heifers of the Jersey breed, 8 ± 2.5 months old, with an average weight of 160 ± 15 kg were used. The animals were randomly divided into 2 latin squares 4X4, balanced and contemporary, in a 2X2 factorial arrangement. The experimental period was 21 days, 14 for the adaptation of the experimental diets and 7 for the data collection. The experimental diets were: 1 - Cane Silage without Fibrozyme®; 2 - Cane Silage with Fibrozyme®; 3 - Corn Silage without Fibrozyme®; 4 - Corn Silage with Fibrozyme®. Animals received 20g of Fibrozyme®/day. The supply of enzyme increased the digestibility of DM in both diets with different forage sources and increased digestibility of NDF was more evident when the enzyme was supplied to heifers fed with sugarcane silage. The addition of fibrolytic enzyme in silages increased the ratio of acetate to propionate. The animals fed with sugarcane silage presented a lower microbial protein synthesis than those fed corn silage. The lowest values of nitrogen and urinary nitrogen intake were observed in heifers fed with sugarcane silage with addition of enzyme, while the other treatments showed similar nitrogen intake and urinary production. Enzyme addition treatments demonstrated a decrease in urea excretion. The addition of enzyme increased the time spent with feeding and, consequently, tended to decrease the idleness of the animals. Fibrolytic enzyme significantly increased digestibility of NDF in cows fed sugarcane silage or corn silage, with similar NDF results in cows fed corn silage without enzyme supplementation. The enzymatic product altered the ingestive behavior of cows, increasing the efficiency of chewing and feeding. The enzymatic product altered the ingestive behavior of cows, increasing the efficiency of chewing and feeding.