Concentrate and crude protein levels in growing Nelore bulls diet. Intake and digestibility

It was aimed to evaluated the nutrients intake and digestibility of growing and finish Nellore bulls diets. It were used 32 non-castrated Nellore bulls, with 240 kg, confined in individual stalls, in the growing phase, and 16 animals with 360 kg in the finishing phase. The treatments were four concentrate levels (20, 40, 60, and 80%) and two percentages of crude protein (15 and 18%) in the diets. It was used an experimental design randomized, with four replicates, in the growing, phase and two, in the finish phase. It was used Tifton 85' bermudagrass hay as roughage. In growing phase, the maximum dry matter (BM), organic matter (OM), crude protein (CP) and total carbohydrates (TCHO) intakes of 7.60, 7.23, 1.30, and 5.77 kg/day were estimated for 45.94, 46.94, 40.91, and 48.18% of concentrate, respectively. The fiber intake presented linear reduction with the increase of the concentrate level in the diet, while the NDF digestibility did not differ. The TND maximum, 72.33%, was estimated with 40.4% of concentrate and the crude protein content did not effect the nutrient digestibility in the growing phase. In the growing phase, maximum DM, OM, CP and TCHO intakes of 7.60, 7.23, 1.30, and 5.77 kg/day were estimated for 45.94, 46.94, 40.91, and 48.18% of concentrate, respectively. The NDF intake linear by reducted as concentrate level in the diet incresead, while the NDF digestibility did not differ. In the finishing phase, the DM, CP, NDF and ADF intakes were linearly reduced was the concentrate levels increased, while the OM, TCHO and TDN intakes were not affected. The DM and TCHO digestibility linearly increased, while the CP and EE were not affected by the concentrate levels in the diets.