Mycoplasma bovis is a multi-disease producing pathogen in domestic animals causing mastitis, arthritis, and pneumonia. Seroprevalence of antibodies to M. bovis in yaks from Tibet and Hongyuan area of Sichuan Province in China were investigated by a commercial enzyme-linked immunosorbent assay kits. Results showed that in 2012, 44.3 and 50.8% serum samples were found positive to M. bovis in Tibet and Hongyuan area; and 44.5 and 55.3% positive serum samples in 2013, respectively. The investigation indicates an increasing trend in M. bovis infection in Chinese yaks in Tibet and Hongyuan area of Sichuan Province. These observations raise a serious public concern considering a significant loss due to such infection in yaks.

Key words: ELISA, Hongyuan, Mycoplasma bovis, Seroprevalence, Tibet, Yak