The experiment was conducted on 20 Marwari mares of age between 4-10 years, during transitional period (January - March). They were randomly divided into two groups. In group 1 (control group; n=10) ovarian ultrasonography was done using linear array transducer to detect dominant follicle (≥30mm) on any of the ovaries in mares showing estrus signs. Mares were covered twice after 36 hours interval. | Synchronization of estrus using prostaglandins and HcG in indigenous mares during transitional period