PROTEIC-ENERGETIC SUPPLEMENTATION FOR CROSSBRED DAIRY HEIFERS SUBMITTED TO ALIMENTARY RESTRICTION BEFORE DRY SEASON

Daily weight gain, costs and nutritional aspects were evaluated in two groups of 11 dairy heifers (Holstein/zebu) weighing 177.6 +/- 6kg and with 15.7 +/- 4 months of age. In the preexperimental period, for 49 days (April 7 to May 26), 11 heifers were kept in a stall and submitted to forced restriction in their daily dry matter intake, which resulted in weight loss of 2.9kg, related to their initial weight. Eleven other heifers were maintained free on the pasture, where they gained 30.2kg during the period. After this pre-experimental period, both groups were kept on the same grazing area and received a proteic-energetic supplement containing 30% urea, 30% NaCl and 40% of wheat middlings. Both groups were weighed every 21 days; on the same data, only the group of forced alimentary restriction was evaluated for its body condition score (BCS). The animals under alimentary restriction had higher daily weight gain throughout the dry season. At the end of the experimental period, the difference between the two groups was 15.6kg and the values of the BCS were different in the period of body weight loss and in the re-growth phase; i.e. for a loss of 14.3kg of body weight the heifers had -0.68 units in their BCS. For a gain of 48.2kg of body weight, during the proteic-energetic supplementary phase, the same heifers had a surplus of 0.31 units of BCS.