Silagens e fenos em associação à palma forrageira para vacas em lactação e ovinos

Abstract

This study was conducted to determine the performance of lactating Holstein/zebu cows fed diets based on spineless cactus with different fiber sources, namely sorghum silage, sunflower silage, guandu hay, leucena hay and elephant-grass hay. Five cows (body weight 500 kg and average milk production 12kg) were used in 5 x 5 Latin square design with 12-day periods (7 days for adaptation and 5 days for data collection). Intakes of dry matter, organic matter, crude protein, total and nonfiber carbohydates were similar for all dietary treatments. However, cows fed the hay diets consumed more neutral detergent fiber than cows fed the sunflower silage diet. Fiber source had no effect on milk production or milk composition. However, 4% fat corrected milk and feed efficiency were higher for cows fed sunflower silage than for those fed the hay diets. Digestibility coefficients of dry matter, crude protein and nonfiber carbohydrates were not influenced by forage source. No significant differences among treatments were observed for the purine derivatives excretions, microbial nitrogen synthesis and microbial protein synthesis. The microbial protein synthesis efficiency (104.48 g / kgNDT) was not significantly changed across diets, as well as the urea excretion in the urine and plasmatic and milk concentration of urea and N-urea. It was concluded that sunflower silage was a superior source of fiber for lactating cows fed spineless cactus-based diets; does not change the microbial protein synthesis, concentrations of purine derivatives and urea.