Performance and feeding behavior of dairy heifers submitted to grazing in frequêncy and levels of suplementation

Abstract

This study aimed to evaluate the effect of supplementation frequency and levels in the dry season of the year, on body development and feeding behavior of crossbred Gir x Holstein. The heifers were grazing on Brachiaria brizantha cv. Marandu, in a randomized block design with a 2 x 2 factorial arrangement, with seven replicates per treatment. We used the daily supply additional or alternate mixing the trough considering 0.5% and 1.0% of body weight (BW) per day. At the end of each grazing cycle (42 days) the animals were weighed and measured as the height at withers, heart girth, rump length and body condition. The considered behavioral variables were grazing time, ruminating time, idle time, trough time. It was found that the productive performance of heifers that were submitted to the supplementation of 1.0% BW/day had higher average daily gain (0.643 kg/animal/day) than those undergoing supplementation of 0.5% of the BW/day (0.513 kg/animal/day). There were no differences in weight gain among the different supplementation daily or alternate averaging 0.561 and 0.595 kg/day, respectively. The animals supplemented on alternate days showed more trough time (P<0.05). All the behavioral variables had been influenced by the hour of the day (P<0.01), strengthening the importance of the knowledge about the distribution of the seeding behavior throughout the day, in order to identify the best schedules for supplementation. The reduction in the frequency of supplementation did not affect the animals performance, but the animals supplemented on alternate days spent longer in the trough.