This work was to evaluate the effect of different forage levels in the diet on the intake and apparent digestibility of dry matter (DM), organic matter (OM), crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), total carbohydrate (CHO), gross energy (GE) and total digestible nutrients (TDN). Thirty five pure Holstein bull calves, 60 days old with initial average live weight (LW) of 78 kg, were allotted in a completely randomized experimental design with nine replications per diet, except for the 10% forage diet, with eight replicates. 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. The chromium oxide was used to obtain the fecal DM excretion estimates. The total carbohydrate was calculated as 100 - (%CP + %EE + % ash). The TDN was calculated as (cCP - fCP) + 2.25 (cEE - fEE) + (cCHO - fCHO), where c means intake and f fecal excretion. There were no effects of forage level in the diet on DM and OM intakes (kg/day, % LW and g/kg.75) and CP and CHO (kg/day and % LW). The NDF intake (kg/day, % LW and g/kg.75) increased while the EE and TDN intake decreased linearly, in function of the increased forage level in the diet. The apparent digesitibilities of DM, OM, CP, EE, CHO and GE decreased linearly in function of increased level of forage in the diet, while the NDF apparent digestibility was not affected. The intakes of EE, NDF and TDN and the apparent digestibility coefficients of DM, OM, EE, CP, CHO and GE were affected by forage level in the diet.
Holstein calf; digestibility; feed intake; forage level