Abstract: The number of donkey reared in China has reached to the first place in the world. The eco-geographic distribution is concentrated in 35-44°N latitudes with the Yangtze River as the south boundary and 46°50′N latitude as the north boundary. In the west, it can extend to the Qinghai-Tibet plateau with an altitude of 4000-4500m above sea level. China’s donkey breeds can be classified into three groups in terms of their natural distribution, ecological conditions and body types. Group 1: the small-type donkeys in pastoral areas of western and northern China with body height below 110cm, such as Xinjiang donkeys,Liangzhou donkeys,Xiji donkeys, Mongolian donkeys, and northeast donkeys. Group 2.the large and medium-type donkeys in plain and hilly agriculture areas of central China with body height of 110-130cm and over 130cm such as Guanzhong donkeys, Qingyang donkeys, Jiami donkeys, Dezhou donkeys etc. Group 3: the small type donkeys in plateau and mountain areas of southwestern China such as Sichuan donkeys, Tibet donkeys and Yunan donkeys.

Key words: Brassica chinensis, Protective enzymes, Lead, Cadmium, Chromium