Abstract: Objective: To investigate the difference of renal function among yak, migrated cattle on Qinghai-tibetan plateau and lowland cattle, and to further explore the characteristics of renal to adapt chronic hypoxia.Methods: The serum samples of yak(n=84) were collected at 3 000 m,3 500 m,4 000 m and 4 300 m respectively,meanwhile the serum samples of migrated cattle on plateau (n=22) and lowland cattle (n=39) were also collected.The levels of blood urea nitrogen(BUN), creatinine(Crea), blood urea nitrogen/creatinine(BUN/Cr), uric acid(UA), carbon dioxide binding rate(CO₂cp), glucose(GLU) in serum were measured by using fully automatic blood biochemical analyzer. We analysed the differences among the above renal functions.Results: With the altitudeincreased, the results showed the levels of UA and CO₂cp of yak were increased significantly, as compared to cattle, the levels of BUN and BUN/Cr were increased significantly compared with migrated cattle on plateau and lowland cattle, thelevels of CO₂cp and GLU were decreased significantly compared with lowland cattle. As compared to migrated cattle on plateau, the levels of BUN and BUN/Cr of lowland cattle were decreased significantly, the levels of UA and CO₂cp were increased significantly.Conclusion: The results indicated that theyak were adaptedto the plateau hypoxia environment and migrated cattle maybe not adapt to the low oxygen environment, they were under the stress situation.

Key words: chronic hypoxia, yak, migrated cattle, renal function