İneklerde Ovsynch Protokolünde İkinci Gonadotropin- Releasing Hormon (GnRH) Enjeksiyonu Yerine Human Chorionic Gonadotropin (hCG) Kullanımının Etkinliğinin Araştırılması

Bu çalışma, laktasyondaki ineklerde klasik ovsynch protokolünde ikinci Gonadotropin-Releasing Hormon (GnRH) uygulaması yerine human Chorionic Gonadotropin (hCG) uygulamasının plazma progesteron düzeyi ve gebelik oranı üzerine etkinliğinin belirlenmesi amacıyla yapıldı. Çalışmanın başlangıcında 36 baş sağmal inek rastgele iki uygulama grubuna ayrıldı: OV-GnRH (n=20) ve OV-hCG (n=16) grubu. Bütün ineklere 0. gün GnRH ve 7. gün PGF2? enjeksiyonu yapıldı. Dokuzuncu gün OV-GnRH grubundaki ineklere GnRH enjekte edilirken, OV-hCG grubundakilere ikinci GnRH yerine hCG enjekte edildi. Son enjeksiyon (9. gün) ve tohumlama günü preovulatör folliküllerin büyüklükleri 7,5 MHz transrektal prob kullanılarak ultrason ile ölçüldü. Bütün inekler ikinci GnRH ya da hCG enjeksiyonundan 16-18 saat sonra tohumlandı. Plazma progesteron (P4) düzeyinin tespiti için tohumlama günü (ST) ve sonrasındaki 5 ve 12. günlerde heparinize tüplere kan örnekleri toplandı. Tohumlamadan 24 saat sonra ovulasyon, 30 gün sonra ise gebelik kontrolü ultrasonla gerçekleştirildi. Son enjeksiyon ve tohumlama günü yapılan ultrasonografik muayenede pre-ovulatör folliküllerin ortalama büyüklükleri (±S.E.M.) OV-GnRH grubunda 1,41±0,06 ve 1,53±0,06 cm, OV-hCG grubunda ise 1,56±0,08 ve 1,67±0,06 cm olarak belirlendi. Ovulasyon ve gebelik oranları sırasıyla OV-GnRH grubunda %90 ve %40, OV-hCG grubunda ise %93,75 ve %56,25 olarak tespit edildi. Gruplarda pre-ovulatör folliküllerin ortalama büyüklükleri, ovulasyon ve gebelik oranları arasındaki farklar istatistiki açıdan önemli bulunmadı (P>0,05). Sunulan çalışmada elde edilen verilere dayanarak, ineklerde ovsynch protokolünde ikinci GnRH yerine hCG uygulamasının da yapılabileceği kanısına varıldı.

INVESTIGATION OF EFFICACY OF HUMAN CHORIONIC GONADOTROPIN (HCG) INSTEAD OF SECOND GONADOTROPIN-RELEASING HORMON INJECTION (GNRH) AT OVSYNCH PROTOCOL IN COWS

This study was carried out to determine the efficacy of replacing the second Gonadotropin-Releasing Hormone (GnRH) with human Chorionic Gonadotropin (hCG) on pregnancy rate and plasma progesterone level in ovsynch protocol in cows. Thirty-six cows were randomly divided into two treatment groups: OV-GnRH (n=20) and OV-hCG (n=16) groups. All cows were treated with GnRH on day 0 and PGF2? on day 7. On day 9, cows in OV-GnRH group.were injected with GnRH while those in OV-hCG group were injected with hCG. Pre-ovulatory follicle sizes (±S.E.M.) were examined by ultrasonography on 9 and 10 days. All cows were inseminated 16-18 h after the last injection. Ovulation and pregnancy examinations were performed by ultrasonography at 24 h and on 30 day after the insemination, respectively. Blood samples were collected on artificial insemination day and then at 5 and 12 days for progesterone assay. Mean pre-ovulatory follicle sizes on last injection and insemination days were determined 1.41±0.06 and 1.53±0.06 cm in OV- GnRH group, 1.56±0.08 and 1.67±0.06 cm in OV-hCG group. Ovulation and pregnancy rates were 90% and 40% for OV-GnRH group and 93.75% and 56.25% for OV-hCG group. Pre-ovulatory follicle sizes and ovulation and pregnancy rates did not differ significantly between groups (P>0.05). It is concluded that hCG can be used instead of the second GnRH injection in ovsynch protocol in cows according to the results obtained from this study.

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