Manipulation of the time and ovulation rate and improvement of lambing rate in Zandi ewe via progesterone and melatonin hormones

The aim of this study was to determine the effects of Progesterone and Melatonin hormones on ovulation synchronization and improvement of pregnancy rate of Zandi ewes. In this study out of breeding season, 156 ewes were selected and divided into four groups. The first group (control) received no hormone injections. On ear of second group (Melatonin) were implanted a piece of Regulin contained Melatonin hormone and after 35 days, the rams released into the ewes. The ewes of third group (Progesterone) were received cidr for 12 days and 600 IU eCG intramuscularly and 48 hours after cidr removal the rams were released into the ewes. The fourth group (Melatonin and Progesterone) at first received a piece of Regulin and after 22 days received 600 IU eCG intramuscularly and 48 hours after cidr removal the rams were released into the ewes. Reproductive parameters including parity rate, lambing rate, twinning rate, litter size, weight and number of lambs were investigated. The results of this study showed that using of cidr and eCG could improve reproductive parameters compared the other groups (P< 0.05).