Çağatay TEK, Ahmet SABUNCU, Alper BARAN, Mithat EVECEN

Postpartum sütçü ineklerde GnRH+$PGF_{2 alpha}$ ve hCG+ $PGF_{2 alpha}$ uygulamalarının, östrus senkronizasyonu ve fertilite üzerine etkileri

Çalışmada, sütçü ineklerde postpartum 35-45. günlerde GnRH+PGF2a ve hCG+PGF2a uygulamalarının östrus gösterme ve fertilite üzerine etkilerinin araştırılması amaçlandı. Materyal olarak; aynı işletmede, eşit bakım ve beslenme şartları altında tutulan, sağlıklı, 3-7 yaş arasında bulunan ve postpartum 35-45. günler arasındaki 117 baş Holstein ırkı sütçü inek kullanıldı, inekler rastgele üç eşit gruba ayrıldılar. Birinci gruba (n=39): 0. gün 2000 IU hCG İM (Pregnyl®, Organon), 7. gün 500 pg Cloprostenol Na İM (Estrumate®, DİF) ve 9. gün 12,6 ug Buserelin acetate İM (Receptal®, Hoechst), ikinci gruba (n=39): 0. gün 12,6 ug Buserelin acetate İM (Receptal®, Hoechst), 7. gün 500 pg Cloprostenol Na İM (Estrumate®, DİF) ve 9. gün 2000 IU hCG İM (Pregnyl®, Organon ) verilirken, üçüncü gruba ise (n=39): 11 gün ara ile iki kez 500 mg Cloprostenol Na İM (Estrumate®, DİF) uygulandı. Birinci ve ikinci grupta bulunan ineklere 9. gün, üçüncü gruptakilere ise ikinci Cloprostenol Na uygulamasını takiben 48 saat sonra, transrektal ultrasonografik muayene yapılarak ovaryumlarinda bulunan folliküllerin çapları ölçüldü. Birinci ve ikinci gruptaki ineklere 9. gün ilaç uygulamalarını takiben 12. ve 24. saatlerde, üçüncü grupta ise ikinci Cloprostenol Na (Estrumate®, DİF) uygulamasından sonra 60. ve 84. saatlerde suni tohumlama uygulandı. Tohumlama sonrası 28. ve 55. günlerde uygulanan transrektal ultrasonografik muayene ile gebelik teşhisi yapıldı. Dominant folliküle sahip olma, 28. ve 55. günlerdeki gebelik ve embriyonik ölüm oranları yönünden birinci grup ile ikinci grup ve ikinci grup ile üçüncü gruptaki inekler arasında istatistiksel olarak herhangi bir fark bulunmazken (p>0.01), birinci grup ile üçüncü grup arasındaki 28. günlerde ve aynı gruplardaki dominant folliküle sahip olanların 28. ve 55. günlerinde elde edilen gebelik oranları arasındaki farklar istatistiksel anlamda birinci grup lehine önemli bulundu (p0.01). Çalışmada her üç grupta östrus gösterme oranları bakımından istatiksel bir fark bulunmadığı, tohumlama öncesi ovulasyonu ve gebeliği garanti altına almak amacıyla yapılan Gonadotropin Releasing Hormon uygulamalarının hCG hormonuna benzer sonuçlar verdiği saptandı. Ancak birinci grupta, tohumlama öncesi hormon uygulanmayan üçüncü gruba göre istatistiksel olarak daha yüksek gebelik oranları elde edilmesi, ineklerde tohumlama öncesi Gonadotropin Releasing Hormon kullanılmasının gebelik oranlarının artırılması yönünden yararlı olduğu sonucunu ortaya çıkardı.

The effects of GnRH+$PGF_{2 alpha}$ and hCG + $PGF_{2alpha}$ applications in postpartum dairy cows on oestrus syncronization and fertility

The aim of this study was to determine the effect of GnRH + $PGF_{2 alpha}$ and hCG + $PGF_{2 alpha}$ applications on oestrus and fertility in dairy cows postpartum between days 35 and 45. In this study, 117 healthy, 3-7-year-old Holstein dairy cows from the same farm under similar husbandry conditions were used and they were in postpartum days between 35 and 45. Cows were divided equally into three groups randomly. Group I (n = 39): on day 0, 2000 IU hCG IM (PregnylR, Organon) was given, on day 7, 500 mg Cloprostenol Na IM (EstrumateR, DİF), and on day 9, 12.6 mg Buserelin acetate IM (ReceptalR, Hoechst). Group II (n = 39): on day 0, 12.6 mg Buserelin acetate IM (ReceptalR, Hoechst) was given, on day 7, 500 mg Cloprostenol Na IM (EstrumateR, DİF), and on day 9, 2000 IU hCG IM (PregnylR, Organon). Group III (n = 39): they received 500 $mu$g Cloprostenol IM (EstrumateR, DİF) twice, at 11-d intervals. The diameters of the follicules in ovaria were measured in the cows in groups I and II on day 9, and in the cows in group III 48 h after the second Cloprostenol Na application, using transrectal ultrasonography. The cows in groups I and II were artificially inseminated 12 and 24 h after applications on day 9. The cows in group III were artificially inseminated 60 and 84 h after the second Cloprostenol application. On day 28 and day 55 after insemination, pregnancy was diagnosed using transrectal ultrasonography. No statistical differences were found between the cows in groups I and II and the cows in groups II and III in terms of dominant follicule, pregnancy and embryonic death on day 28 and day 55 (p > 0.01). The rates of pregnancy between groups I and III on day 28 and the cows in the same groups which have dominant follicule on day 28 and day 55 differ statistically, being positive for group I (p < 0.01). No statistical differences were found between groups I and III for parameters of dominant follicule, pregnancy and embryonic death on day 55 (p > 0.01). In this study it was found that there were no statistical differences among the three groups in terms of showing oestrus and it was also found that application of GnRH, to stimulate ovulation, before insemination and pregnancy resulted in similar findings as hCG application. However, group I had higher pregnancy rates (statistically significant) than group III, which did not receive hormones before insemination. These results indicate that it will be useful to apply GnRH before insemination to increase pregnancy rates.

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