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ABSTRACT:The efficiency of medroxyprogesterone acetate (MAP) sponges in combination with either pregnant mare serum gonadotrophin (PMSG) or cloprostenol (PGF 2α ) for inducing and synchronizing the estrous cycle in non-lactating Kivircik ewes was investigated during the natural non-breeding season. All ewes (n = 69) were treated with 60 mg MAP sponges for 12 days. In addition, each ewe received an intramuscular injection of either 1.5 ml sterile saline solution (n = 18); 125 µg PGF 2α (n = 14); 500 IU PMSG (n = 18) or 500 IU PMSG and 125 µg PGF 2α (n = 19), 48 h before the sponge removal. Cervical artificial insemination (AI) with diluted fresh semen was performed at a fixed time (48 and 60 h) following progestagen withdrawal. The different groups estrous response for the first 24 ± 6 h and within 120 h, time to onset and duration of the induced estrous, and pregnancy rate was found to be 36.2%, 81.6%, 41.7 ± 2.3 h, 29.6 ± 1.5 h, and 54.5%, respectively. There were significant differences between groups MAP and MAP/PGF 2α and their with the two latter groups (MAP/PMSG, MAP/PMSG/PGF 2α ) in terms of the onset of induced estrous (P < 0.05) and between groups MAP and MAP/PGF 2α in terms of the duration of induced estrous (P < 0.05) and between the first two groups (MAP, MAP/PGF 2α ) and the latter two groups (MAP/PMSG, MAP/PMSG/PGF 2α ) in terms of estrous response at the first 24 ± 6 h (P < 0.05). These results indicate that, the use of MAP/PMSG, rather than MAP or MAP/PGF 2α , was effective in the attainment of early and compact induction and synchronization of estrous in non-lactating Kivircik ewes during the natural non-breeding season.

Synchronization of oestrus has been used to increase reproductive effi ciency in most animals, including ewes. The aim of the present study was to compare the effect of the length of a progestagen treatment (12 d vs. 6 d) on synchronization effi ciency (oestrus response, time to onset of oestrus and duration of oestrus) and fertility rate using fl uorogestone acetate (FGA) progestagen sponge treatment with pregnant mare serum gonadotropin (PMSG) administration applied at different times of sponge removal. Ewes (n = 68) were divided into two groups; long term (LT, n = 33) and short term (ST, n = 35) groups treated with FGA progestagen sponges. At the end of intravaginal sponge treatment period the animals of each group were divided into the 3 subgroups in relation to time of PMSG (300 IU) treatment. PMSG treatment was applied 24 h before sponge removal, at sponge removal and 24 h after sponge removal for LT1 and ST1, LT2 and ST2, and LT3 and ST3, respectively. Each ewe was inseminated intra-cervically twice with skim cow milk-diluted semen (1000 × 10 6 motile cells/ml) 40 h and 60 h after sponge removal. Non-return rates (NRR-30) were monitored from 12 day after sponge removal to 30 day with the aid of teaser rams. Onsets of oestrus response and oestrus cessation were signifi cantly different (P < 0.05) between the ST and LT treatment groups. Synchronization of oestrus was tighter in LT than ST group. Except for oestrus cessation, other indicators studied were not different in the ST subgroups. In the ST subgroups the oestrus cessation of the ST1 (88.7 ± 15.4 h) was the shortest and differed from ST3 (120.0 ± 14.2 h) (P < 0.05). No statistical difference was observed among all studied indicators for LT groups according to application time of PMSG (P > 0.05). The NRR-30 and lambing rate of the ST and LT after timed AI were 35.7% and 31.0% and 32.1% and 28.6%, respectively (P > 0.05).

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The aim of the current study was to evaluate the effect of egg yolk and different soybean lecithin concentrations on the efficiency of ram semen cryopreservation and to test the fertilizing ability of frozen-thawed ram semen. Ejaculates with a thick consistency, rapid wave motion (3-5), and >70% initial motility were pooled. Pooled semen were then divided into four groups and diluted at 1/5 (semen/extender) with 1%, 3%, 6% lecithin (L1, L3 and L6) or 20% egg yolk (EY20) using the two-step dilution method. As expected, the results of the current study showed that both motility and the rates of defective acrosomes in sperm were negatively affected by the cryopreservation procedure (P<0.001). The motility values of at 5°C and post-thawed semen in the EY20 group were significantly higher than those in the L1, L3 and L6 groups (P<0.05). There were no differences in motility rates among the lecithin groups at the dilution, cooling, equilibration or post thawing stages (P>0.05). The results of in vitro fertilization, as assessed by the rate of blastocyst formation, were more successful in the EY20 group than those noted in different lecithin groups. In conclusion, freezing ram semen with an extender containing egg yolk could yield better post-thaw sperm parameters and embryonic development compared to lecithin containing extenders. Keywords: Cryopreservation, Lecithin, Egg yolk, Ram semen, IVF Tris-Bazlı Sulandırıcılarda Yumurta Sarısı ve Soya Lesitininin Eritme Sonrası Koç Spermasının Kalitesi ve in vitro Fertilite Üzerine Etkisi ÖzetBu çalışmanın amacı, yumurta sarısı ve farklı lesitin konsantrasyonlarının koç spermasının dondurulabilirliği üzerine etkisini değerlendirmek ve dondurup çözdürülen koç spermasının fertilizasyon yeteneğini tespit etmektir. Kitle hareketi (3-5) ve >%70 motiliteye sahip ejakülatlar birleştirildi (pooling). Pooling yapılan sperma dört gruba bölündü ve %1, %3, %6 (L1, L3 ve L6) lesitin veya %20 yumurta sarısı (EY20) içeren sulandırıcılar ile 1/5 (sperma/sulandırıcı) oranında iki aşamalı sulandırma yöntemi kullanılarak sulandırıldı. Bu çalışmanın sonucunda; motilite ve akrozomal bozukluk oranlarının dondurma prosedüründen olumsuz yönde etkilendiği tespit edildi (P<0.001). EY20 grubunun 5°C'de ve eritme sonrası motilite değerleri L1, L3 ve L6 gruplarına göre yüksek bulundu (P<0.05). Sulandırma, soğutma, ekilibrasyon ve eritme sonrası aşamalarda motilite oranları bakımından lesitin grupları arasında farklılık saptanmadı (P>0.05). Blastosist oranları bakımından değerlendirilen in vitro fertilizasyon sonuçlarına göre, EY20 grubunun farklı lesitin gruplarından daha başarılı olduğu tespit edildi. Sonuç olarak, yumurta sarısı içeren sulandırıcı ile dondurulan koç spermasının lesitin gruplarına göre eritme sonrası spermatolojik özellikler ve embriyonik gelişim bakımından daha üstün olduğu tespit edildi.