The objective of this work was to evaluate the effects of the forage to concentrate ratio in the nutrient intake by 25 crossbred steers with initial 310 kg LW. Five full fed diets based on tanzaniagrass hay and concentrate, with different forage to concentrate ratio (85:15, 70:30, 55:45; 40:60; and 25:75) were used. A quadratic effect was observed for the concentrate level in the diet on the intake of dry matter (DM), organic matter (OM), crude protein (CP) and, gross energy (GE), with a maximum intake for DM, 2.87% PV; OM, 118 g/w0,75 e 2.7% PV; CP, 1.52 kg/day; 18.2 g/w0,75; and 0.42% PV e GE, 536 Kcal/ w0,75, for the levels of 39; 44, 42; 43; 39, e 38 e 46% of concentrate, respectively. A quadratic effect was observed for the digestible dry matter (DDM), digestible organic matter (DOM), digestible protein (DP) and digestible energy (ED), with a maximum intake for DDM of 7.07; 83.8; and 1.91; DOM, 6.91; 81.4, and 1.86; and DP, 1.13; 13.4; e 0.31, in kg/day, g/w0,75 and %LW, respectively, for the levels of 52, 49, 48, 54, 51, 50, 41, 28 e 37% of concentrate. For DE, the maximum intake were 30.6 Mcal/day and 356 kcal/ w0,75 , for the levels of 62.0 and 57.0% of concentrate, respectively. The maximization of the digestible nutrient intake for the maximum efficiency of nutrient utilization occurred with the intake of NDF ranged from 1.25 to 1.02% LW for crossbred steers
beef cattle; concentrate level; intake; nutrient
