Abstract: [Objective] To explore selenium level of livestock milk in Inner Mongolia. [Method] A total of 48 mixed milk representative samples that involves 188 individual animals of Bactrian camel, Mongolian horse, Saanen goat and Holstein cow, were collected from 8 banners/counties from the northeast to the west part of Inner Mongolia Autonomous Region. Selenium was determined by atomic fluorescence spectrometry, and statistical analysis and comparison were conducted. [Result] There were extremely significant regional differences on selenium content among each of the four livestock milk in Inner Mongolia: selenium in Bactrian camel milk from Alagxa Left Banner[（5.96±0.41） μg/kg] was twice higher than that of Ewenki Autonomous Banner [（2.89±0.12） μg/kg], selenium in Holstein cow milk from suburb of Hohhot City [（8.74±0.22） μg/kg] was about 3.8 times higher than that of Ewenki Autonomous Banner [（2.26±0.41） μg/kg], while, selenium in Mongolian horse milk from Zhenglan Banner[（6.65±0.57）μg/kg] was 6.5 times higher than that of Ewenki Autonomous Banner[（1.02±0.42） μg/kg]. In the west part of Inner Mongolia, selenium of goat milk from Hanggin Banner[（8.95±1.32） μg/kg] slightly higher than Wuyuan County [（6.28±0.80） μg/kg] but without significant differences （P>0.05）. Selenium in different animal milk also were significantly different. Generally, Bactrian camel, Saanen goat and Holstein cow had higher milk selenium level. Selenium level of Saanen goat milk was significantly higher than that of Mongolian horse milk （P<0.05）. Selenium data were all very much dispersed, implies that the selenium in milk not only has west to east regional differences, but also has local geographical abundance effect, may also influenced by foreign feed and forage, and salt blocks as well. [Conclusion] In Inner Mongolia, selenium level of livestock milk is generally lower, and milk selenium of northeastern part was significantly lower than that in central and western part. Selenium-rich feeding is an effective way to high quality development for the dairy livestock farming and dairy processing industry as well.

Key words: selenium, milk, Bactrian camel, Mongolian horse, goat, Holstein cow