Steroid hormone profile and ovulatory response in buffaloes superovulated with Ovagen.

摘要

16 buffaloes were injection with Ovagen (a sheep pituitary preparation) in 8 decreasing doses over 4 days (total dose, 1.6 units) starting on day 13-15 of an oestrous cycle and Lutalyse (PGF2alpha; 2 doses each of 25 mg given 48 and 60 h respectively after starting the Ovagen treatment). Eight of the buffaloes were also treated with 250 mug gonadorelin (GnRH) 48 h after the 1st injection of Lutalyse; the remaining buffaloes were not given GnRH (control group). The buffaloes were inseminated 48, 60 and 72 h after the 1st injection of Lutalyse. Five or 6 days after oestrus, the numbers of corpora lutea and unovulated follicles were recorded. Blood samples were collected daily from all animals from 1 day before until 14 days after treatment. Oestrus was detected in 50 and 62.5% of GnRH-treated and control animals respectively. The onset of oestrus and its duration after Lutalyse treatment did not vary between groups. Mean ovulation rate (number of corpora lutea) was low in both groups (1.25+-0.25 after GnRH and 1.50+-0.38 in controls). Five buffaloes in each group had 0 or 1 corpora lutea. No significant differences were observed between progesterone concentration in the blood between groups at the start of treatment; values declined to <1 ng/ml afterLutalyse treatment. Peak oestradiol concentration did not differ between the groups and was not related to ovulation rate. It was concluded that Ovagen alone or in combination with GnRH failed to induce a superovulatory response.