EFFECT OF BODY CONDITION, BIOSTIMUIATION AND TEMPORAL WEANING ON THE ANESTROUS POSTPARTUM INTERVAL AND THE RATE OF PREGNANCY IN SIMMENTAL BEEF COWS

Abstract

Seventy three Simmental beef cows were used to evaluate the effect of body condition al parturition, high (HBC) or low (LBC) and biostimulation with bull (B) or without bull (O) over anestrous postpartum interval. Besides these, temporal weaning (W) or without it (o) were included to evaluate also the effect on rate of pregnancy due to fírst service of artificial insemination (AI), under synchronized estrous. Cows were assigned to treatments completely random. in 2 x 2 factorial arrangement with covariate, utilizing X² test for analysis of rate of pregnancy at first AI service. Considering progesterone (P₄) concentration and first corpus luteum (CL.) detection, ovarian cyclical activity started on 6,8,11, and 15 weeks postpartum (P< 0,01). for cows HBC-B. HBC-O, LBC-B and LBC-0, respetively. Rate of pregnancy at first Al service were 70, 56, 30, 30, 33, 22, 25, and 13%,for cows HBC-B-W, HBC-B-o, HBC-O-W. HBC-O-o, LBC-B-W, LBC-B-o, LBC-O-W, and LBC-O-o, respectively. Conclusion: anestrous postpartum interval could be reduced in cows with moderate body condition (BC> 5,5) and biostimulated with bull soon after parturition, and the rate of pregnancy improved due to both factors together.