2012, Cilt 28, Sayı 3, Sayfa(lar) 149-153
The effect of gonadotropin-releasing hormone or human chorionic gonadotropin administration at mating on lambing performance in Konya Merino yearling ewes
Mehmet Köse1,2, Ahmet Hamdi Aktaş2, Mesut Kırbaş2, Bülent Bülbül2
1Dicle Üniversitesi, Veteriner Fakültesi, Doğum ve Jinekoloji Anabilim Dalı, Diyarbakır, Türkiye
2Bahri Dağdaş Uluslararası Tarımsal Araştırma Enstitüsü, Konya, Türkiye
Keywords: Konya Merino, yearling ewes, GnRH, hCG, lambing performance
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Aim: In this study, it was aimed to determine the effects of the exogenous gonadotropin-releasing hormone (GnRH) or human chorionic gonadotropin (hCG) application at mating on lambing performance in synchronization and following cycle in Konya Merino yearling ewes.

Materials and Methods: Thirty six yearling Merino ewes, aging 16-20 months, were used as material. Estrus of ewes was synchronized with 4 μg GnRH on d 0 and 150 μg prostaglandinF2α (PGF2α) on day 5, intramuscularly. After PGF2α injection, the ewes detected to be in estrus were mated with a ram, whose fertility was known previously, and they were divided into three groups. Group I (n=14) were injected 200 IU hCG, Group II (n=12) were injected 4 μg GnRH, and Group III (control group, n=10) were injected 1 mL placebo at mating. Pregnancy was diagnosed on day 30 by using transrectal ultrasonography.

Results: In the present study, pregnancy, birth, twinning rate and lambing performance were 85.71%, 85.71%, 33.3% and 1.14 in hCG group, 75.0%, 66.67%, 12.5%, and 0.75 in GnRH group, and 100%, 80%, 37.5% and 1.10 in control group, respectively. There was no significant difference among groups for lambing performance and studied reproductive parameters (p>0.05).

Conclusion: In conclusion, the injection of GnRH or hCG in Merino ewes at mating was not effective on lambing performance.