[目的]为了解内蒙古奶牛昏睡嗜血杆菌（Hs）的感染状况。[方法]调查12 个盟（市）23 个旗（县）的65 个奶牛场,包括大型规模化奶牛场20 个、小型规模化奶牛场21 个、家庭牧场24 个。采集2 650 份阴道拭子样品,用荧光PCR方法检测Hs。[结果]除乌海市以外,其余11 个盟（市）均出现Hs阳性场。在23 个旗（县）中,只有7 个未检出阳性场,其余16 个均检出阳性场,阳性旗（县）比例高达69.6%。大型规模化奶牛场、小型规模化奶牛场和家庭牧场个体阳性率分别为：18.2%（182/1 000）、22.9%（240/1 050）和21.2%（127/600）;农区、牧区、半农半牧区、阳性率分别为：15.6%（109/700）、13.5%（135/1 000）和32.1%（305/950）,平均个体阳性率为20.7%（549/2 650）。[结论]内蒙古奶牛场Hs感染普遍,应加大防控力度。

[Objective] To understand the infectious status of Histophillus somni（Hs）in cows in Inner Mongolia.[Method] 65 dairy farms in 23 counties of 12 prefecture-level cities were investigated,including 20 large-scale dairy farms,21 small-scale dairy farms and 24 family farms. 2 650 vaginal swabs were collected to detect Hs DNA by fluorescent PCR. [Result] The results showed that 11 cities had positive cases of Hs except for Wuhai City. Moreover,16 of 23 counties have been detected positive cases except for 7 negative counties and the proportion of positive counties was as high as 69.6%. The individual positive rates of large-scale dairy farms,small-scale dairy farms and family farms were 18.2%（182/1 000）,22.9%（240/1 050） and 21.2%（127/600）,respectively,and the positive rates of agricultural areas,pastoral areas and farming-pastoral areas were 15.6%（109/700）,13.5%（135/1 000） and 32.1%（305/950）, respectively. The average individual positive rate was 20.7%（549/2 650）. [Conclusion] This study indicatd that Hs infection was very common in dairy farms in Inner Mongolia,prevention and control should be strengthened.