Reproductive Performance After hCG or GnRH Administration of Long-Term Progestagen Treatment of Fat Tailed Ewes During Seasonal Anoestrus

Öz

This research was carried out to evaluate the effect of hCG or GnRH two days after long-term progestagen treatment on the reproductive performance of Mehraban ewe during seasonal anoestrus under field conditions. A total of 75 ewes pretreated with intravaginal progestagen sponges left in situ for 14 days and all ewes were treated with Pregnant Mare Serum Gonadotrophin at the time of sponge removal. Two days after removal of sponge, the ewes in two groups were injected (im), either with hCG (hCG group) or with GnRH analogue (GnRH group) and the other group remained untreated and served as control. Blood samples were collected on day 19 after sponge removal from all animals to measure serum concentration of progesterone in order to pregnancy diagnosis. The reproductive performance of the Mehraban ewes in all groups was assessed by lambing data. The pregnancy rate of ewes was highest in the hCG group (86.4%), compared to the control (60%; P<0.05) and GnRH (69.2%; P>0.05) groups, respectively. The percentage of lambing rate of the ewes which lambed from mating at the induced oestrus was highest in the hCG group (85.7%), when compared to the control (58.3%; P<0.05) and GnRH (66.7%; P>0.05) groups. The highest proportion of twin lamb birth rate was recorded in the hCG group (61.1%), compared to the control (57.1%; P>0.05) and GnRH (31.3%; P<0.05) groups. The hCG group recorded significantly greater mean single and twin lamb birth weight compared to the control group (P<0.05). It can be concluded that hCG injection, two days after sponge removal, increases prolificacy and can improve reproductive performance of Mehraban ewes outside the breeding season, which is in high importance for sheep holders from economical point of view.

Key Words: Ewe, anoestrus, progestagen, hCG, GnRH, prolificacy

Anahtar Kelimeler

• Ewe, anoestrus, progestagen, hCG, GnRH, prolificacy

ANÖSTRUS DÖNEMİNDE YAĞLI KUYRUK KOYUNLARA UZUN SÜRELİ PROGESTAGEN UYGULAMASINI TAKİBEN YAPILAN hCG VEYA GnRH ENJEKSİYONUNUN REPRODÜKTİF PERFORMANS ÜZERİNE ETKİSİ

Öz

Bu çalışmada saha şartlarında bakılan Mehraban ırkı koyunlara anöstrus döneminde uzun süreli progesteron uygulamasının bitiminden iki gün sonra uygulanan hCG veya GnRH hormonlarının reprodüktif performans üzerine etkinliğini araştırıldı. Kullanılan 75 adet koyunun vajinasına progestagen emdirilmiş süngerler yerleştirildikten sonra 14 gün beklendi, süngerlerin çıkarıldığı günde tüm koyunlara gebe kısrak serum gonadotropin hormonu uygulandı. Sünger çıkarılmasından iki gün sonra çalışma koyunlarından ilk gruba hCG (im) enjeksiyonu yapıldı (hCG grup) ve diğer gruba GnRH analoğu enjekte edildi (GnRH grup), çalışma grupları dışında kalan koyunlar kontrol grubu olarak ayrıldı. Sünger çıkarılmasından 19 gün sonra serum progesteron konsantrasyon tayini ile gebelik kontrolü yapılması için tüm hayvanlardan kan alındı. Tüm gruplarda yer alan Mehraban koyunlarının reprodüktif performansları kuzulama oranları değerlendirilerek belirlendi. Gebelik oranında gruplar içinde en yüksek değer hCG grubunda (%86,4) tespit edilirken bunu sırasıyla kontrol (%60; P<0,05) ve GnRH (%69,2; P>0,05) grubu takip etmektedir. Östrusu uyarılan ve çiftleştirilen koyunlardan hCG grubunun (%85,7) kuzulama oranı, GnRH grubu (%66,7; P>0.05) ve kontrol grubu (%58,3; P<0,05) ile karşılaştırıldığında daha yüksek bulunmuştur. Grupların ikiz doğurma oranları karşılaştırıldığında en yüksek oran hCG grubunda (%61,1) tespit edilirken, kontrol grubunda (%57,1; P>0,05) ve GnRH grubunda (%31,3; P<0,05) daha düşük oranlar tespit edildi. Tek ve ikiz kuzuların doğum ağırlıkları karşılaştırıldığında hCG grubunda doğan yavruların doğum ağırlıkları kontrol grubundan belirgin şekilde yüksek olduğu gözlenmiştir (P<0,05). Sonuç olarak sezon dışı dönemde Mehraban ırkı koyunlara sünger çıkarılmasından 2 gün sonra uygulanan hCG enjeksiyonunun elde edilen yavru sayısını ve üreme performansını arttırıcı etkisi bulunmuştur, elde edilen bu artışlar koyun yetiştiricileri için ekonomik açıdan çok önemli bir noktadır.

Anahtar Kelimeler: Koyun, anöstrus, progestagen, hCG, GnRH, verimlilik

Anahtar Kelimeler

• Koyun, anöstrus, progestagen, hCG, GnRH, verimlilik

Kaynakça

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