Comparison reproductive performance in kermani ewes treated with two synchronization methods and subsequent ecg treatment out of the breeding season
Authors:Int J Biol Med Res. 2012; 3(2): 1485-1489
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A completely randomized design experiment was carried out using seventy eight multiparous kermani ewes during out of season breeding to compare flourogestone acetate (FGA) sponges and controlled internal drug release (CIDR) dispensers to synchronize estrous. Intravaginal progestagen was administered for a 13-day period. Upon progestagen withdrawal, doses received 350, 500 and 650 IU equine chorionic gonadotrophin (eCG) intramuscularly. Teaser rams (1/10 ewes) were introduced 1 d after treatment removal to detect estrus. Ewes were subjected to fertile rams 48-60 h after FGA and CIDR removal. Twenty one days after mating, blood samples were taken from jugular vein in 10-ml vacuum tubes (venoject) for pregnancy diagnosis. The results of this experiment showed that both types of pessaries were effective when used with eCG. Although two progestagen treatments had significant effect on estrus response (92.89 in FGA vs 82.45 in SIDR), time to the onset of estrus did not differ significantly (32.65 vs 31.1h). Enhancing the level of eCG administration in sponge treated ewes led to a decrease in percentage of ewes in estrus, however non significant changes was observed in SIDR treated groups. Results indicated that the use of FGA and CIDR intravaginal progestagen treatments could be efficient in synchronization of estrus in sheep under warm arid area. The CIDR device is comparable to the FGA sponge for estrus synchrony during the out-of- season breeding and reasonable response can be achieved with the use of eCG.