Superovulation in nonseasonal Japanese native goats, with special reference to the developmental progression of embryos

Treatment for superovulation with pregnant mare serum gonadotropin (PMSG) and follicle stimulating hormone (FSH) was carried out in nonseasonal breeder Japanese goats which are widely used as a substitute model for cattle in various studies in Japan. The proportion of females that came into estrus (93 and 99%) and the interval between PGF(2) administration and estrus (1.5 to 2.0 days) did not differ between females treated with PMSG and those treated with FSH. The number of normal embryos recovered was significantly higher (P<0.01) in FSH-treated (9.4 +/- 5.6) femals than in PMSG-treated females (5.7 +/- 4.4). The developmental stage of embryos recovered from 1.0 to 8.5 at 0.5-d intervals after mating is also described. The development to the two-cell, four-cell, eight-cell, morula, blastocyst and zona-free blastocyst stage was first observed 1.5, 2.5, 5.0 to 5.5, 6.0 and 6.5 d, respectively, after human chorionic gonadotropin (hCG) injection.