The results showed that it can achieve a better result that the mean number of viable embryo was 11.50~18.91 when donors were superovulated from the day of 12th to 17th in estrus period.

• 结果表明；在供体发情周期12~17天中任一天开始超排均能取得较好的超排效果；可用胚平均数为11.；50~18