The effects of different dietary concentrate levels on the intakes of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), ether extract (EE), total carbohydrates (TC), total digestible nutrients (TDN), calcium (Ca), phosphorus (P), magnesium (Mg), sodium (Na) and potassium (K) were evaluated. The live weight (LWG) and the empty body gains (EBG), feed:gain ratio (F:G), carcass gain (CG) and the carcass productivity in relation to live weight (LWCP) and to empty body weight (EBW) were also evaluated. Twenty nine F1 Simental x Nelore bulls, averaging 17 months of age and initial live weight of 354 kg, were used. In the beginning of the experiment, five animals were slaughtered, as reference, to estimate the initial empty body weight (IVBW). The remaining animals were allotted to a completely randomized design according to the concentrate level in the diets: 25, 37.5, 50, 62.5, and 75%. Animals were fed full until a pre-established slaughter weight of 500 kg. As forage, the coast-cross (Cynodon dactylon) and brachiaria (Brachiaria decumbens) hays were used. The intakes of DM, CP, EE and TDN increased while that of NDF reduced linearly with the concentrate increase in the diets. The intakes of P, Mg and K were influenced linearly and that of Ca on a quadratic way by the dietary concentrate levels. LWG, VBG and CG increased and FC decreased linearly as a function of the dietary concentrate levels, whereas LWCP and VBCP were not affected by the dietary concentrate levels. The animal performance was improved with the use of higher concentrate contents in the diets
crossbred bovines; performance; concentrate
