Prevalence, Risk Factors, and Antibiogram Analysis of Bovine Mastitis in Northern Bangladesh

Mastitis remains a major constraint to dairy production in Bangladesh, particularly in high-demand regions. This study investigated the prevalence, risk factors, and antimicrobial resistance patterns of major pathogens associated with bovine mastitis in Northern Bangladesh. A total of 488 milk samples from 122 randomly selected milking cows were tested through clinical inspection and the California Mastitis Test (CMT). Positive samples were subjected to bacterial culture and antimicrobial susceptibility testing using the disc diffusion method. The overall cow-level prevalence was 35.24%, with 27.86% sub-clinical and 7.37% clinical cases. At the quarter level, prevalence was 21.72%. Among 166 bacterial isolates, Staphylococcus spp. (41.56%) was predominant, followed by Streptococcus spp. (23.49%), E. coli (17.47%), Klebsiella spp. (12.65%) and Bacillus spp. (4.82%). Gentamicin (100%) and Streptomycin (92.20%) were the most effective antibiotics, whereas Cefixime (100%) and Amoxicillin (87.40%) showed the highest resistance rates. Major risk factors included late lactation stage, high milk yield, previous mastitis history, and poor hygiene. In contrast, breed, age, and parity were not significant. These findings highlight a high prevalence of mastitis, predominance of Staphylococcus spp., and rising antimicrobial resistance, identify associated risk factors, and rising antimicrobial resistance profiles in Northern Bangladesh.