EFFECT OF NUTRITION ON THE PERFORMANCE, B ODY CONDITION AND FERTILITYOF POSTPARTUM CROSSBRED DAIRY-COWS

The objective of this work was to evaluate the effect of nutritional v ariation upon ponderal performance and the fertility of postpartum cro ssbred dairy cows, with a good body condition (scores greater than or equal to 3.0) at parturition. Animals were divided into two groups of 24 each and fed on two levels of energy, restricted and normal (respec tively, 70% and 100% of the National Research Council, requirements), 22 days after parturition. Body weight and body condition scores of th e cows at artificial insemination were reduced (P < .01), by the level of restriction. The daily milk production was reduced in the cows wit h restricted diets (P < .01). The intervals from parturition to first estrus and to artificial insemination for cows fed on the restricted a nd normal levels (34.8 and 34.1 days and 54.8 and 57.3 days), respecti vely, were similar (P > .05). Pregnancy rates of cows fed on the restr icted level was reduced (37.5 vs 87.5%) compared with cows fed on the normal diet.