Reproductive performance evaluation of different prostaglandins for repeated synchronization program in postpartum dairy cows: preliminary results

This trial evaluates reproductive performance in a early-routine estrus synchronization program using two different PGF2? . Cows were administered D(+)cloprostenol sodium (n=88; Group A) or dinoprost (n=78; Group B) between 35-42d postpartum. Pedometers were used to detect estrus. Evaluation of secondary signs of estrus and evaluation of vaginal mucus quality was made prior to AI. When estrus was not detected by day14 following PGF2? , the treatment was repeated, up to a maximum of 3 time. Progesterone were analysed by RIA in blood samples collected on the day of treatment. There was no difference in the estrus detection to both PGF2? treatments (A=79.7 vs B=75.6%). No treatment-related variation was recorded in respect of estrus signs (A=90.2 vs B=94.9%) nor good mucus quality (A=95.08 vs B=88.13%). First-service conception rate and conception rate at 200d were 45.9 and 65.2% in group A, and 22.0 and 67.9% in group B, respectively. There was no difference for the interval from parturition to first-AI; however, group A showed a significantly shorter interval from parturition to conception and services than group B (101.5 vs 122.6; 1.9 vs 2.6). Progesterone levels were lower in cows that needed 2 or 3 repeated treatment. In those individuals estrous response and conception rates were also lower. D(+)cloprostenol proved to be as efficacious for estrus response as dinoprost, but better fertility results were reported with D(+)cloprostenol. Introduction The use of postpartum estrus induction and synchronization programs to shorten the calving interval and thus increase the economic profitability of the herd has been widely studied. In order to optimise the calving interval, it is essential to restore postpartum reproductive status as soon as possible; this is dictated largely by the resumption of hormonal cycling and uterine involution, both of which are in turn governed by the negative energy balance characteristic of