Folliküler gelişimin farklı aşamalarında bulunan östrustaki kısraklarda hCG uygulamalarının ovulasyona etkisi

Bu çalışma üreme mevsiminde ve östrusta olan kısraklarda gerçekleştirildi. Ovulasyonun uyarılması amacıyla optimal hCG uygulama zamanı belirlenmeye çalışıldı ve folliküler gelişim takip edilerek belirli follikül büyüklüğüne ulaşmış kısraklara hCG uygulandı. Araştırmanın materyalini yaşlan 7 ile 14 arasında değişen 39 kısrak oluşturdu. Östrüs belirtileri gösteren kısrakların dominant follikül çaplan ölçüldü. Daha sonra kısraklar follikül büyüklüğüne göre; 30-34 mm (Grup I, n=9), 35-39 mm (Grup II, n=l 1), 40-44 mm (Grup III, n=10) ve >44 mm (Grup IV, n=9) olmak üzere dört gruba aynldı. Follikülün çapı ölçüldükten hemen sonra kas içi yolla 3000 IU hCG (Pregnyl®) enjekte edildi. Enjeksiyon-ovulasyon aralığı (saat), östrüs süresi (saat) ve enjeksiyon sonrası 48 saat içinde ovulasyon oranı (%) sırasıyla; I. grupta 106.7+18.4, 179.1±32.8 ve 22.2, II. grupta 58.9+9.4, 130.9+16.0 ve 72.7, III. grupta 48.0+8.0, 96.0+7.2 ve 70.0 ve IV. grupta ise 50.7+10.2, 98.7+10.9 ve 77.8 olarak tespit edildi. Enjeksiyon-ovulasyon aralığı ve 48 saat içinde ovulasyon oranlan bakımından I. grup ile diğer gruplar arasında istatistiki olarak önemli derecede fark bulundu (p

Anahtar Kelimeler:

at, ovulasyon, yumurtalık follikülleri, kızgınlık, kısrak, üreme mevsimi, HCG

The effect of hCG administration on ovulation in different follicular stage in mares in estrus

This study was conducted in mares in estrus during breeding season. The optimum time of hCG injection was investigated and hCG was administered to mares that have certain follicle diameter. Thirty-nine mares, between 7 and 14 years of age, were used in the present study. The dominant follicle diameters were measured in mares which showed signs of estrus. Then, mares were divided into four groups according to size of follicle; 30-34 mm (Group I, n=9), 35-39 mm (Group II, n=ll), 40-44 mm (Group III, n=10) and >44 mm (Group IV, n=9). Mares were intramuscularly injected 3000 IU of hCG (Pregnyl®) immediately after measurement of follicle diameter. It has been found that the injection-ovulation interval (hr), oestrus duration (hr) and percentage of ovulation within 48 hours after treatment (%) were 106.7+18.4, 179.1±32.8 and 22.2 in group I, 58.9+9.4, 130.9+16.0 and 72.7 in group II, 48.0+8.0, 96.0+7.2 and 70.0 in group III and 50.7+10.2, 98.7+10.9 and 77.8 in group IV, respectively. There was a significant difference between the groups I and other groups in point of the injection-ovulation interval and the rate of ovulation within 48 hours after hCG administration (p<0.05). In addition, it was showed that the duration of estrus was longer in group I than those of group III and group IV. In conclusion, it is determined that the administration of hCG could induce ovulations within 48 h in mares which showed estrus and had a follicle of at least 35 mm during breeding season. However, it was observed that the follicle size had no influence on ovulation induction when the follicles reached a diameter of 35 mm or larger.

Keywords:

horses, ovulation, ovarian follicles, oestrus, mares, breeding season, HCG,

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