Buffaloes, like cattle and goats, play a major part in the subsistance economy of rural people in Bangladesh. These livestock species are prone to the intramammary infections (IMI), which are associated with a lot of economic impact to the farmers. The prevalence and importance of clinical and sub-clinical mastitis (SCM) have been reported in cows and goats from Bangladesh and this study was undertaken to evaluate the indirect tests and bacteriological methods for the prevalence of SCM associated with host risk factors and antibiotic sensitivity profiles of bacterial isolates recovered from milk samples of apparently healthy mammary quarters of lactating buffaloes of an organized farm in Bangladesh during the period from June to November 2010. A total of 120 quarters milk samples from 30 available apparently healthy lactating cross-bred (Nili-Ravi x Murrah and Nili-Ravi x local) buffaloes were subjected to the Whiteside test (WST), the surf field mastitis test (SFMT) and the California mastitis test (CMT); those positive by the WST, SFMT and CMT were 35 (29.16%), 32 (26.66%) and 39 (32.50%) with an overall 56.66% prevalence of SCM in lactating buffaloes. The test with the highest diagnostic performance, for both animal-wise and quarter-wise prevalence of SCM was the CMT (56.66% and 32.50%), followed by the WST (53.30% and 29.16%), and the lowest was SFMT (50.00 and 26.66%), respectively. The highest prevalence of SCM was recorded at > 9 to 12 years of age (23.33%), 4th parity (16.67%) and late lactation (30.0%). The daily average milk production was insignificantly (p > 0.05) decreased in buffaloes (4.5 +/- 0.72 liter / day) that had IMI (SCM) in comparison to buffaloes (4.8 +/- 0.88 liter / day) without IMI. The CMT positive milk samples (n = 39) were subjected to bacterial culture isolation (the gold standard test for comparison of indirect mastitis test). Among the bacterial isolates of IMI, Staphylococcus spp. (30.77%) showed the highest frequency, followed by Streptococcus spp. (20.51%), Bacillus spp. (15.39%) and Escherichia coli (12.82%) as a single infection, and also recorded as mixed infection (12.82%) and 7.69% remained as unclassified bacterial growth. Moderate to high antibiotic sensitivity of Staphylococcus spp., Streptococcus spp., Bacillus spp. and E. coli was obtained with gentamicin, ciprofloxacin, enrofloxacin and chloramphenicol, but these organisms were found mostly resistant or less sensitive to ampicillin, amoxicillin and streptomycin. It may be concluded from these results that there is a high prevalence (56.66%) of SCM in buffaloes in Bangladesh and that the associated pathogens have already developed resistance due to indiscriminate use of antibiotics and accordingly, there is a need for proper attention to control of mastitis in buffaloes.
