Bovine mastitis in subtropical dairy farms, 2005-2009

The purpose of this study was to investigate the incidence of Clinical Mastitis (CM) and Subclinical Mastitis (SCM), isolation and identification of the major pathogens and test the antimicrobial resistance of milk bacterial isolates in subtropical dairy farms in Guangxi region (south of China) between 2005 and 2009. The average percentages of blind quarter(s) at cow and quarter region (south of China) between 2005 and 2009. The average percentage of blind quarter(s) at cow and quarter level were 11.5 and 3.7%, respectively. The incidence of CM at cow and quarter level were 807 and 3.7%, respectively while that of SCM at cow and quarter level were 48.8 and 19%, respectively. A total of 105 and 56 microorganisms were isolated from the 109 CM and 67 SCM samples, respectively. The most common bacterial isolates from CM cases were S. aureus (29.5%), E. St. agalactiae (17.9%). The antimicrobial sensitivity test indicated that all the antimicrobial agents (except for ampicillin) showed lower proportion of resistant isolates of all isolated bacteria (except for C. neoformans), among the employed antimicrobials, Ruyanxiao showed the lowest proportion of resistant isolates.