Abstract: Through the isolation and identification of the main pathogens of dairy cowmastitis and the drug sensitivity test in Liangshan area, it provides theoretical guidance forguiding the clinical rational use of antibiotics in Liangshan dairy farms and improving theeffect of antibiotics on the prevention and treatment of dairy cow mastitis. Methods are sampling, enrichment culture, bacterial identification, drug sensitivity test, statistical analysis of data. The results show that 134 of 193 mastitis milk samples are isolated from 12 pathogens, among which two and two types of bacteria account for 48.5%; a total of 234 non-duplicate strains are isolated. The top five isolation rates are: 63 strains of Staphylococcus (26.9%), 56 strains of Escherichia coli (23.8%), 42 strains of Klebsiella pneumoniae (17.9%), 24 strains of Enterococcus (10.3%), 13 strains of Streptococcus Strain (5.6%). The results of the susceptibility test of 10 bacteria out of 12 bacteria, including Escherichia coli, Staphylococcus, and Klebsiella pneumoniae isolated in this test, indicate that both Gram-positive and Gram-negative bacteria show varying degrees of resistance to the 17 common antibiotics selected in the test, some strains show severe multi-drug resistance and some strains are resistant to some kind of drugs up to 100%.

Key words: cow mastitis in Liangshan area, pathogen identification, drug sensitivity test