Synchronization of estrus in ewes from the Synthetic bulgarian dairy population by progestagen and different follow-up treatments

The aim of the present study was to induce estrus synchronization in ewes after administration of progestagen for 12 days and various subsequent treatments (with FFA, GnRH analogue or no treatment) after cessation of its action. The experiment was conducted in August, 2022, with 27 sheep from the Synthetic Bulgarian Dairy Population. All ewes were treated with vaginal sponges, containing 30 mg FGA (duration of stay - 12 days) and the formation of experimental groups was according to follow-up treatment after sponge removal: I group - experimental animals were treated with 400 UI of PMSG at the time of removal of sponges. II group - the sheep were treated with 1 ml of GnRH analogue, containing busorelin acetate 0.004 mg/ml, 24 hours after sponge removal. III group – no treatment after sponge removal. The next parameters were studied: estrus synchronization rate, fertility and fecundity were studied. The estrus synchronization rate was the highest for I group - 100% and the lowest for II group - 66.67%. Fertility was highest in III group - 87.50%, and lowest in II group - 50.0%. Fecundity was highest in I group - 171.43%, while in other groups it was 133.33% and 128.57%, respectively, for II group and III group. Based on the obtained results, it could be concluded that GnRH analogue treatment, given solely 24 hours after sponge removal, didn’t have the synchronization effect as the classical follow- up treatment with PMSG. No follow-up treatment after sponge removal was better alternative that GnRH treatment.