Bagaço de cana de açúcar in natura em substituição parcial à silagem de milho na dieta de ovinos

Abstract

Two experiments were conducted in the Sheep section of the Experimental Farm of the Federal University of Mato Grosso, to evaluate the effect of partial replacement of corn silage by sugar cane bagasse in natura (BIN) on intake, apparent digestibility of components nutritious, ruminal parameters, synthesis of microbial nitrogen, nitrogen balance, performance and economic viability. The diets were composed of 40 % forage and 60 % concentrate. Corn silage was replaced by BCIN on 0; 17.5; 35.0; 52.5 and 70 %, corresponding to 0, 7, 14, 21 and 28% inclusion in the diet. In the first experiment 40 lambs mixed breed, neutered males, aged approximately 105 days and an average initial weight of 20.16 ± 0.59 kg were divided into 20 pens of 4.06 m² each were used. The experiment was conducted in a randomized block design with five treatments and four repetições.The intake of dry matter (DM) was not altered in treatments evaluated, whereas the intake of neutral detergent fiber (NDF) and neutral detergent fiber corrected for ash and protein (NDF) as well as the digestibility of DM, CP and NDF increased linearly (P < 0.05) as a result of increased participation in the BCIN diets. The increasing inclusion of BIN reduced average daily gain, and the best cost benefit was observed with the substitution of BIN 7%. In the second experiment, five male sheep, adults, cannulated in the rumen with an average initial weight of 65 ± 2.07 kg, allotted to a 5 x 5 Latin square were used. BIN The inclusions did not influence (P < 0.05) DM digestibility, but apparent digestibility of NDF, NDF and total carboidatos descresceram linearly. The NAR and ruminal pH were not affected (P < 0.05) by the addition of BIN, with averages of 6.16 and 8.03 mg/dL, respectively. Excretion of purine derivatives were not affected, with excretion of total purine 29.67 mmol/day, resulting in 25.68 g/day of microbial N. Consumption and nitrogen losses varied with quantities greater than 14% of the BIN diet. Given the nutritional and animal performance, the substitution of corn silage BIN by up to 7% reduces costs and improves gross margin in lamb finishing.