The economic effects of an estrus synchronization protocol using prostaglandin in beef heifers

We estimated the effect of estrus synchronization on reproduction, production and economic outcomes in 272 beef heifers randomly allocated to a synchronized Test group or an unsynchronized Control group. The Test group received A1 upon estrus detection for 6 days followed by PGF2 treatment of heifers that had not shown estrus by day 6 (PGF/6). In both groups A1 was continued for 50 days, followed by a 42-day bull breeding-period. Heifers were followed through their second breeding season and until they had weaned their first calves. Sychronization resulted in a reduction in median days to first insemination (8 vs. 11 in the Test and Control groups, respectively, P < 0.0 1) and niedian days to calving of calves born to Al (14 vs. 20, P = 0.04). There was no significant difference in pregnancy rate to the A1 period (60.0% vs. 51.8%. P = 0.18), final pre-nancy rate (82.2% vs. 83.2%, P = 0.87) or pregnancy rate to the subsequent breeding season (96.0% vs. 95.0%, P = 1.00). Although mean calf weaning mass was not significantly, different (207.0 kg vs. 201.4 kg P = 0.32). the total mass of calves weaned in this study was 14,843 kg vs. 13.060 kg and the benefit: cost ratio for synchronization was 2.8. It was therefore concluded that a PGF/6 protocol may affect the total mass of calves weaned by changing days to calving, weaning rate, the ratio of male: female calves born and/or the birth mass of calves. (c) 2008 Elsevier Inc. All rights reserved.