مرکز منطقه ای اطلاع رساني علوم و فناوري - مقايسه سه روش همزماني فحلي گوسفند با استفاده از پروژستاژن ها در فصل توليد مثل

چكيده لاتين :

The objective of this study was to compare three estrus synchronization protocols in sheep during the breeding season using progestagens (CIDR, norgestomet and sponge). Fifty-nine ewes were divided into three groups considering their weight, age and breed including Norgestomet (n=21; age: 31.3±8.4 months; weight: 57±2.8 kg), CIDR (n=20; age: 31.2±8.4 months; weight: 59.1±3.04.kg) and Sponge (n=18; age: 30.6±8.4 months; weight: 58.9±2.64 kg).Ewes in norgestomet group received a half implant of norgestomet (1.5 mg)used in cattle. Ewes in CIDR and sponge groups received an intravaginal device of CIDR (330 natural progesterone) and sponge (40 mg flugestone acetate).All progestagen treatments were considered for 14 days. At the termination of treatments, ewes were given an intramuscualar injection of 250 IU PMSG. At the time of progestagen removal, the appearance of vaginal discharge was investigated. Twenty-four hours after the termination of treatment, harnessed ram was used to detect estrus and at the same time continous observation was carried out to identify standing estrus. Ewes were mated 12 hours after standing estrus by fertile ram. Pregnancy was diagnosed on Day 30 after mating via ultrasonography. Frequency of vaginal discharge, fertility, lambing rates and prolificacy were analyzed using Chi-square test. The majority of ewes that received CIDR (17/19) and sponge (14/14) had a vaginal discharge at the time of device removal; whereas, none of the ewes treated with norgestomet had vaginal discharge. Estrus was detected within 6 hours after ram introduction in 90.5, 89.5 and 78.6 percent of ewes treated with norgestomet, CIDR and sponge, respectively (P>0.05). Fertility of norgestomet, CIDR and sponge Groups were 66.7, 52.6 and 71.4 percent, respectively (P>0.05). Lambing rate were 110.5, 72.2 and 100 percent in norgestomet, CIDR and sponge Group, respectively (P>0.05). The prolificacy of norgestomet, CIDR and sponge Groups were 1.5, 1.3 and 1.4, respectively (P>0.05). In conclusion, all three estrus synchronization protocols used in this study had similar result concerning reproductive indices. However, due to the speed of implantation, lower cost and lack of vaginal discharge, the use of norgestomet for synchronizing estrus cycle in ewes is recommended.