This work was conducted aiming to evaluate the effect of different forage levels in the diet on the average daily dry matter intake (DMI), average weight gain (AWG), feed:gain ratio and carcass yield. Thirty-six pure Holstein bull calves, 60 days old with initial average live weight (LW) of 78 kg, were allotted in a completely randomized experimental design. The animals were ad libitum fed with diets contained 10, 25, 40, and 55% of forage, on the DM basis, using chopped coast-cross (Cynodon dactylon) grass, ground corn and soybean meal, which constitute diets with approximately 16% CP. Animals were weighed at each 28 days period, with more frequent weighing for the animals near to the pre stabilized slaughtering weights of 190 ± 10 and 300 ± 10 kg, for the groups 1 and 2, respectively. Forage levels of the diet for both groups did not affect the dry matter intake. There was increased linear effect of forage level on feed:gain ratio expressed as LW or empty body weight (EBW). The average weight gain expressed in LW and EBW decreased linearly in function of the levels of forage in the diet. The hot carcass weight and hot carcass dressing for animals in group 2 were not affected, while the hot carcass dressing of animals from group 1 decreased linearly with the level of forage in the diet. The average daily gain at 28 and 56 days for group 1 and at 28, 56, 84 and 112 days for group 2, reduced linearly with the increasing of forage levels in the diets. The animal performance for both groups was higher with the use of low levels of forage in the diets, but above five months of age, the use of higher forage levels was not harmful to the performance of the animals.
Holstein calf; feed:gain ratio; performance; hay