اثر استراديول بر همزمان كردن فحلي به روش درمان كوتاه مدت با سيدر و گنادوتروپين سرم ماديان آبستن )PMSG( و عملكرد توليد مثل خارج از فصل ميش‌هاي تالشي‌

The effect of estradiol in short-term treatment with CIDR and PMSG on reproductive performance of Taleshi ewes in

The objective of. this study was to determine the effect of estradiol in short-term treatment with Controlled Internal Drug Release (CIDR) and Pregnant Mareʹs Serum Gonadotropin (PMSG) on estrus induction, estrus synchronization, observation period between CIDR withdrawal and estrus, lambing efficiency, prolificacy and lambing rate. Thirty six nonlactating and nonpregnant Taleshi ewes (2-4 years old) were randomly allocated to three groups (n=12/group). Estrus was synchronized with intravaginal insertion of CIDR devices containing 0.3g of progesterone for 7 days. At the time of CIDR removal, PMSG (360 IU) was injected (i.m) to all ewes. The Control ewes (Con) did not receive estradiol benzoate (EB) and others were injected EB (1.5mg) on days 7 (EB7) and 8 (EB8) of the experiment, respectively. A higher number of estrus detected in ewes received EB on days 7 and 8 compared to the control group (P<0.05). Observation period between CIDR withdrawal and estrus in EB7 treatments was significantly lower than Con and EB8 treatments (p<0.05). Estrus in EB7 and EB8 ewes was synchronized better than the control group. Lambing efficiency, prolificacy and lambing rate did not statistically change between the treatment groups. It was concluded that injection of EB, 24 hours after CIDR removal (EB8), without reducing reproductive performance, is an effective method of estrus synchronization.