[目的]动物的繁殖启动都以促性腺激素释放激素（GnRH）为基础,奶牛等非季节性发情动物的GnRH释放受黄体酮（孕酮）的负反馈控制,即奶牛的发情周期变化受孕酮水平的调节。孕酮不仅控制奶牛发情,还影响优势卵泡期内卵母细胞质量、优势卵泡体积大小、排卵、受孕、双胎率及促进子宫内膜发育、抑制宫缩、妊娠维持等生理变化。出于食品安全考虑,生产中注射用黄体酮制剂已在奶牛的泌乳期被禁用。在国内泌乳牛允许使用的孕酮制剂为黄体酮阴道缓释栓。目前使用的该类产品主要是进口孕酮栓产品。为支持我国奶业发展,降低用药成本,国内开始研发生产该类产品。2019年6月,开展试验对比了国产黄体酮硅胶缓释栓（喜达）与同类进口原研产品差异。[方法]通过检测试验组（喜达栓）与对照组（原研孕酮栓）奶牛在放栓前、放栓后48 h、放栓后7 天（撤栓时）血中孕酮水平变化,使用后硅胶栓内孕酮残留比例。同时对比了旧栓第2次使用时上述各时间点的血药浓度变化及输精后受胎情况。[结果]两种产品各自使用后的血中孕酮浓度变化和栓内孕酮残留比例均无差异（P>0.05）,两组产品在首次使用及二次重复利用时的受胎率对比均差异不显著（P>0.05）。[结论]喜达栓在奶牛体内使用效果稳定,可在生产当中替代原研孕酮栓,且不建议二次使用。
[Objective] Reproductive initiation in animals is based on gonadotropin-releasing hormone （GnRH）,the release of GnRH in non seasonal estrous animals such as cows is controlled by negative feedback from progesterone,meaning that changes in the estrus cycle of cows are regulated by progesterone levels. Progesterone not only controlled estrus of dairy cows,but also affected oocyte quality,dominant follicle size,ovulation,conception,twin rate and promoting endometrial development,inhibiting contraction,pregnancy maintenance and other physiological changes during the dominant follicle period.Due to food safety concerns,progesterone preparations for injection in production have been banned during the lactation period of cows. The progesterone preparations allowed for lactating cows in China are intravaginal progesterone insert. At present,the products used are mainly imported progesterone suppository products. In order to support the development of China's dairy industry and reduce medication costs, domestic research and development have begun to produce this type of product. In June 2019,a trial was conducted to compare the differences between domestic intravaginal progesterone insert（Xida）and similar imported original research products. [Method] By detecting the changes in progesterone levels in the blood of cows in the experimental group （Xida Suppository） and the control group （original research progesterone Suppository） before,48 h after and 7 days after suppository withdrawal. The proportion of progesterone residue in the silicone plug after use was detected. Also compare the changes in blood drug concentration at the above time points during the second use of the old suppository and the situation of pregnancy after insemination. [Result] There was no difference in the changes in blood progesterone concentration and the proportion of progesterone residue in the suppository between the two products after use （P>0.05）. There was no significant difference in the pregnancy rate between the two groups when the products were used for the first time and reused for the second time （P>0.05）. [Conclusion] The use of Xida Suppository in cows has a stable effect and can replace the original progesterone suppository in production,and it is not recommended to use it again.
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