A simple superovulation method of a single injection of follicle-stimulating hormone combined with equine chorionic gonadotropin for superovulation of Suffolk ewes during the breeding season: 2. The ovarian response and the embryo qualities.

摘要

Two trials were conducted to investigate the effects of the simple superovulation method on ovarian responses and embryo traits. The ewes were treated with a vaginal sponge containing synthetic progestogen for 12 days in both trials. In Trial 1 (conducted in 1995), 18 ewes received a single injection (F1) or multiple injections (F6) of a total of 20 mg porcine FSH, in combination with an injection of 500 IU equine chorionic gonadotropin (F1+P, F6+P). The injections were given on day -2 (day 0, wasthe day of sponge removal). In trial 2 (conducted in 1996), 24 ewes were given single injections of porcine FSH and equine chorionic gonadotropin at different times: (i) both hormones on day -2 (F-2/P-2), (ii) porcine FSH on day -2 and equine chorionic gonadotropin on day -1 (F-2/P-1), and (iii) both hormones on day -1 (F-1/P-1). A dose of 100 鎔 of an analogue of GnRH was administered on day 1 in Trial 1, and at detection of oestrus in trial 2. Frozen-thawed semen was inseminated in utero using a laparoscope, at 30 and 38 h after sponge removal in trial 1 and at 18 h after detection of oestrus in trial 2. Embryos were recovered on day 7 or day 8. In Trial 1, the mean number of ovulations and the percentage of normal embryos were 6.8 and 16.7 respectively for F1, 15.0 and 36.0 for F1+P, 15.5 and 27.0 for F6, and 20.3 and 44.2 for F6+P. The F1+P group showed results similar to those of F6 and F6+P. In Trial 2, the mean number of ovulations were 17.8 for F-2/P-1, 13.1 for F-2/P-2, and 12.4 for F-1/P-1.The percentage of normal embryos in F-2/P-1 (63.0) was significantly higher than in F-2/P-2 (41.1), and tended to be higher than in F-1/P-1 (43.6). The percentage of freezable embryos in F-2/P-1 (56.2) was higher than in F-2/P-2 (39.3) and in F-1/P-1 (38.5). It was concluded that the simple superovulation method was as effective as multiple injections of porcine FSH and equine chorionic gonadotropin for superovulating Suffolk ewes during the breeding season. [For Pt. I see pp.169-176 of the same numberof the journal.]