The effect of melatonin implants on the reproductive performance of ewes in out of breeding season

The objective of this study was to determine the efficacy of melatonin implants in initiating the breeding season and improving reproductive performance in sheep around of urmia. For this purpose, 116 lactating ewes at around of 3-4 months of postpartum were selected. Females were randomly divided into two groups considering their age, weight and postpartum period. Females in group1 (n=60) received an implant of melatonin (18 mg) melatonin acetate on out surface ear for 40 days. Females in group 2 (n=56) did not received further treatment and were considered as control. After the termination of treatment a few fertile rams were introduced into the flock. Melatonin-treated ewes had their first estrus after ram introduction significantly earlier than did untreated ewes (p<0.05). Fertility or lambing rate for treatment and control groups were 73/3 and 63/3 percent, respectively (p<0.05).The prolificacy and fecundity rate for Melatonin- treated and control groups were 1/34, 1/05 and 1/15, 0/73 respectively (p<0.05).These results revealed that melatonin implant could be useful tool to improved the reproductive performance of ewes in seasonal anoestrus and prior to the normal breeding season.