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体细胞克隆牛生产效率受实验室环节和胚胎移植环节等多种因素的影响。依据前期试验结果，重点分析了胚胎移植数量、季节变化和胚胎移植受体牛生理状态等因素对体细胞克隆牛生产效率的影响。结果表明：移植2枚胚胎比移植1枚胚胎和3枚胚胎能获得较高的妊娠率和产犊率及较低的流产率；在春、夏和秋季（5～9月）进行胚胎移植的效果显著优于冬季（12～1月）；A、B级黄体受体牛的妊娠率显著高于C级黄体受体牛的妊娠率。胚胎移植数量、移植季节和受体牛生理状况均能显著影响克隆牛的生产效率。“,”The production of cloned cattle by somatic cell nuclear transfer ( SCNT ) is affected by many factors both in laboratory and embryo transfer. Based on our experimental data in recent years, factors affecting the production of cloned cattle by SCNT such as embryo transfer numbers, season changes and physiological conditions of surrogate cattle, etc, were analyzed in this study. The results showed that: ( 1 ) Compared with one?or three?embryo transfer, two?embryo transfer could obtain relatively higher pregnancy rate, lower abortion rate and higher calving rate. (2) The efficiency of embryo transfer in spring, summer and autumn ( from May to September) was significantly better than that of winter (from December to January). (3) The pregnancy rate of surrogate cattle with A and B rank corpus luteum is significantly higher than that with C rank. The results indicate that num?ber of transferred embryos, seasonal changes and physiological conditions of surrogate cattle have acritical impact on the production of cloned cattle by SCNT. This study will provide theoretical and experimental basis for further optimization of cloned cattle production program by SCNT, and then improve the efficiency of cloned cattle production.