目的 研究长效黄体酮优化同期发情-定时输精程序技术在规模化奶牛场中的优化应用方案，提高母牛产后配种妊娠率。 方法 选取荷斯坦奶牛与荷弗杂交牛混养试验场，设置6个试验组，产后45 d同期发情-定时输精的荷弗牛（A组）和荷斯坦奶牛（B组）在0-7-9同期发情-定时输精程序技术的基础上，采用第0天增加长效黄体酮、第7天增加孕马血清处理方法优化程序，比较同一输精程序下不同品种的妊娠率；产后自然发情配种的荷弗牛（C组）和荷斯坦奶牛（D组），比较自然发情条件下不同品种的妊娠率；试验场荷斯坦奶牛（E组）用长效黄体酮优化同期发情-定时输精程序配种，对照场荷斯坦奶牛（F组）用基础程序配种，比较同品种不同处理方法的妊娠率。 结果 试验A组、B组长效黄体酮优化同期发情-定时输精程序妊娠率荷弗杂交牛比荷斯坦奶牛提高2.17百分点；C组、D组产后母牛自然发情受胎率荷弗杂交牛比荷斯坦奶牛提高17.31百分点；E组、F组荷斯坦牛受胎率长效黄体酮优化同期发情-定时输精程序比基础程序提高17.35百分点。 结论 在同期发情-定时输精程序技术基础上应用长效黄体酮，能有效提高产后奶牛的受胎率。

Objectives The optimized scheme of applying long-acting progesterone in the program technology of synchronized estrus-timed insemination in large-scale farms was studied to increase the pregnancy rate of mating postpartum dairy cows. Method The mixed farming of Holstein dairy cows and Holstein-Friesian hybrid cattle was selected to set up 6 experimental groups. The 45th day postpartum Holstein cows (Group A) and Holstein cows (Group B) were used to optimize the program by adding long-acting progesterone on day 0 and pregnant horse serum on day 7 based on the program technology of 0-7-9 synchronized estrus-timed insemination. The pregnancy rate of different breeds under the same insemination procedure was compared. The pregnancy rate of different breeds of Holstein cows (Group C) and Holstein cows (Group D) under natural estrus conditions was compared. The experimental Holstein cows (Group E) were farmed with an optimized program of applying long-acting progesterone in synchronized estrus-timed insemination, while the control Holstein cows (Group F) were farmed with a basic program. The pregnancy rate of the same breed under different treatments was compared. Results The optimized program of applying long-acting progesterone in synchronized estrus-timed insemination in experimental groups A and B resulted in a 2.17 percent increase in pregnancy rate in Holstein-Friesian hybrid cattle compared to that in Holstein dairy cows. The pregnancy rate of postpartum Holstein-Friesian hybrid cattle in groups C and D under natural estrus increased by 17.31 percent compared to that in Holstein dairy cows. The pregnancy rate of the Holstein-Friesian hybrid cattle in the E and F groups with optimized program of applying long-acting progesterone in synchronized estrus-timed insemination was 17.35 percent higher than that with the basic program. Conclusions The application of long-acting progesterone on the basis of program technology of applying long-acting progesterone in synchronized estrus-timed insemination can effectively improve the pregnancy rate of postpartum dairy cows.