Forty five crossbreed F1 Limousin x Nellore young bulls, averaging 14 months of age and initial 330 kg LW, were used to evaluate the effects of different concentrate levels (25.0, 37.5, 50.0, 62.5 and 75.0% as DM basis) and two diet balance methods (one, almost isoprotein and the second, changing protein as energy of the diet change) on the intakes of dry matter (DMI) and neutral detergent fiber (NDFI), feed: gain ratio (FG), daily gains of live weight (ALWDG) empty body weight (EBWDG) and carcass weight (CARG). Five animals were slaughtered in the beginning of the experiment as reference, to estimate the initial empty body weight of animals that remained in feedlot. The animals were full fed up to the slaughter weight of 500 kg. The coast-cross grass hay was used as forage source in the diet. A completely randomised design in a 2 x 5 factorial arrangement, with four replicates was used. The two diet balance methods resulted on equal animal performances. The dry matter intake showed a quadratic response, and a maximum values of 8.04 kg DM, 1.99% LW, and 89.22g DM/kg0.75 for the concentrate levels of 41.42, 36.71, and 37.96%, respectively were estimated. The feed: gain ratio, NDFI and days in fed decreased and ALWDG linearly increased as the concentrate levels in the diet increase. The ALWDG and CARG showed quadratic response, with maximum of 1.16 and 0.81 for 61.11 and 64,47% of concentrate level in the diet.
performance; F1 Limousin x Nellore; concentrate level
