Oestrus synchronization in ewes with use of norgestomet and PMSG during non breeding season

In this study efficacy use of norgestomet alone or with using of PMSG in oestrus synchronization during nonbreeding season (late winter) in Urmia suburb were evaluated. For this purpose, 170 healthy Ghezel ewes more than 50 days after partutition, between and 2-6years of age were selected and based on age and weight allocated in to four groups. Groups 1 (n=42) a half of cattle-implant of norgestomet (1/5 mg) was inserted subcutaneously in outer ear of ewes for 12 days. (group 2) (n=40), received norgestomet implant (1/5 mg) for 12 days along with an intramuscular injection of 500 IU PMSG on day 12day of implant insertion. Group 3, (n=40) received same dose of norgestomet in conjucationof 750 IU PMSG on day 12 of implant insertion. Group 4 (n=48) was considered as control. All experiment groups, were given PG on day 10 and implant were removed onday 12 of experiment. About twelve hours after removal of implants, ewes were monitoried for oestrus detetction by use of rams for 10days and served by intact males. Pregnancy was diagnosed by measuring of blood progesterone level on day 30 after mating. The percentage of ewes in the groups I,Ⅱ,Ⅲ and control that showed oesteus within 30 days after end of experiment was 0, 10, 72.5, 0, respectively. In groupsⅡand Ⅲ oestrus wasobserved at 54.3± 2.4 and 57.5±5.9 hours after removal of implants, respectively (p>0/05). Pregnancy rate was 2.5% in the group Ⅱ (norgestomet 500 IU PMSG) vs 25% in the group III (norgestomet 750 IU PMSG) (p