Prevalence of major bacteria causing subclinical mastitis in dairy cows in Northeastern Algeria

Bacterial analyses of 235 milk samples of dairy cattle distributed over 10 farms in Northeastern Algeria, affected by subclinical mastitis diagnosed by the California mastitis test, were carried out over a two-year period (2008-10). Bacterial isolation concerned 80% of the samples. Among the pathogenic agents detected, Gram-positive cocci were the most frequently found, particularly coagulase-negative staphylococci (43%) and Staphylococcus aureus (30%). Escherichia coli was isolated in 14% of the samples. The other bacteria isolated were Streptococcus uberis (4%), Streptococcus agalactiae (3%), Streptococcus dysgalactiae (3%), and more rarely Klebsiella sp. (2%)