Abstract: Yunnan Piebold rabbit is an endangered species, which calls for urgent measures to strengthen efficient breeding as well as the collection and preservation of its genetic materials. Compared with natural estrus control （GroupⅠ）, five different doses of pregnant mare serum gonadotropin （PMSG） （30 g body weight/IU, 35 g body weight/IU, 40 g body weight/IU, 45 g body weight/IU and 70 g body weight/IU, i.e. Groups Ⅱ~Ⅵ） were designed for subcutaneous injection to perform superovulation treatment on Yunnan Piebold rabbit for observing the estrus response and the superovulation effect. The results showed that the high-dose PMSG groups maintained a higher E₂ level at 60~72 h of post-copulation to collect embryo, which reached （44.18±8.97）pg/mL for group Ⅱ and （41.45±13.39）pg/mL for group Ⅲ in serum respectively, significantly higher than those of the other four groups （P<0.05）. The P₄ level was highest in group Ⅳ, significantly higher than the corresponding values for groups Ⅰ and Ⅲ （P<0.05）, while there was no significant difference among the other five groups （P>0.05）. The high-dose PMSG treatment groups were also prone to inducing follicular congestion in rabbits, showing the numbers of congestive follicles increase for group Ⅱ, which are significantly higher than those of the other four treatment groups （P<0.05）. The optimal superovulation effect is achieved for group Ⅴ, with effective embryos of 14.90. It is recommended to use PMSG at a dose of 45 g body weight/IU+5 μg luteinizing hormone releasing hormone A3 for superovulation in practice to obtain premium effect.

Key words: Yunnan Piebold rabbit, PMSG, superovulation, embryo