Prevalence, Risk Factors and Distribution of Major Bacterial Species Causing Clinical and Subclinical Mastitis in Buffaloes

A cross-sectional study with 423 dairy-lactating buffaloes was carried out (n=213 clinical and n=210 from subclinical mastitis animals) to determine major bacterial pathogens involved in causing clinical and subclinical mastitis. The major bacterial species isolated from clinical mastitis were Staphylococcus aureus (33.59%) followed by Escherichia coli, (18.26%), Streptococcus dysgalactiae (11.45%), Micrococcus luteus (10.83%) Streptococcus agalactiae (9.59%), Bacillus cereus (6.34%), Staphylococcus epidermidis (4.02%), Pseudomonas aeruginosa, Streptococcus uberis (1.85%), Bacillus subtilis (1.7%) and Streptococcus pyrogenes (0.46%) respectively. A number of other harmful bacterial species were identified from clinical and subclinical mastitis cases during the study. On the other hand, Staphylococcus aureus (27.97%), Escherichia coli (17.95%), Streptococcus agalactia (13.77%), Bacillus cereus, Streptococcus dysgalactiae (10.43%), Streptococcus uberis (9.18%), Micrococcus luteus (7.39%) and Pseudomonas aeruginosa (2.29%) showed their incidences in subclinical mastitis milk samples respectively. In both clinical and subclinical mastitis cases, these bacterial species displayed a remarkably similar distribution tendency across all three regions. A total 646 quarters were examined from clinical cases, while 479 quarters were from subclinical mastitis. Staphylococcus aureus was the predominant pathogen in all quarters, and hind right quarters were more prone to infection than forequarters in both conditions. In addition, seasonal prevalence was higher in summer months. Furthermore, it is also observed that the above mentioned bacterial species remained persistent in quarters of animals during dry periods.