Digestibilidade dos nutrientes e desempenho produtivo de vacas em lactação alimentadas com torta de amendoim no concentrado

Abstract

The substitution of the soybean meal by the groundnut cake was evaluated in diets for lactating cows on pasture for nutrients intake and digestibility, and productive performance. Eight crossbred cows (Holstein x Zebu), grazing Panicum maximum cv. Tanzania, weighing 507 ± 35 kg, from 45 to 90 days in lactation, were used. Animals were distributed in two Latin Squares 4X4, and fed, daily, 3 kg of concentrate according to levels of groundnut cake in substitution of soybean meal: 0.00; 33.33; 66.67 and 100% on the dry matter of the concentrate ration. Dry matter, organic matter, crude protein, neutral detergent fiber, non-fibrous carbohydrates and total digestible nutrients intakes were not affected by the substitution. The ether extract intake increased as the substitution levels by groundnut cake increased. It was not observed any effect on the digestibility coefficients of dry matter and the nutritional fractions. Daily milk production and corrected for 3.5% of fat, and feed efficient were not influenced by the treatments. Levels of plasma and milk urea nitrogen were similar among the levels of substitution of soybean meal by groundnut cake (17.88 and 16.12 mg/dL, respectively). Plasma urea nitrogen was affected by the time of the collection, which the highest concentration occurred from four to six hours after feeding. The groundnut cake can substitute the soybean meal in diets for lactating cows on pasture, because the dry matter intake and milk production were not altered.