This study was to evaluate the effects of different levels of forage in the diet on the intake and apparent absorption of calcium (Ca), phosphorus (P), magnesium (Mg), potassium (K) and sodium (Na). 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 replicates per diet, except for the 10% forage diet, with eight replications. 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 constitutes diets with approximately 16% CP. The apparent absorption coefficients were obtained by means of digestibility trials, carried out at 120 and 180 days of the animals age, being used the chromium oxide as a marker to estimate the fecal excretion. The maximum daily intake of 10.96 g of P was estimated with 42.40% of forage in the diet. The intakes of Mg and K increased, while the Na decreased linearly and the Ca was not affected by the forage level in the diet. The apparent absorption of Ca, P, Mg and Na were not affected, while the K decreased linearly with the forage levels in the diets. The intakes of P, Mg, K and Na and apparent absorption of the K were affected by the forage levels in the diets.
apparent absorption; Holstein calf; intake; mineral; forage level