Comparative Efficiency of Some Indirect Diagnostic Tests for the Detection of Sub-clinical Mastitis in Cows and Buffaloes

The present study was undertaken to compare five laboratory diagnostic tests for sub-clinical mastitis in cattle and buffaloes and to compute cost, time taken by each test and its ranking for availability, adoptability, interpretability and sensitivity. There were 352 cases with each test type viz. California Mastitis Test (CMT), White Side Test (WST), White Side + Dye (WSTD), Surf Test and Surf + Dye, and 880 cases with each species type (cattle and buffaloes). Result scores (1760 ) for sub-clinical mastitis in each category of negative, trace, single positive, double positive and triple positive by species, and laboratory tests, were analyzed using nonparametric tests. Chi-square statistics showed that CMT was equally effective at both locations (farm vs. laboratory). Correlation further suggested that the association was highly significant. Moreover, cases in category of negative, trace and single positive strongly differed (P<0.05) amongst the laboratory tests. But differences were found vague in double and triple positive categories. However, Chi-square statistics of overall sub-clinical mastitis cases showed that the laboratory tests were significantly different for detecting various categories of sub-clinical mastitis of a crosstabulation. The present findings uncovered stronger (P<0.05) positive correlation of both the WST and WSTD with CMT, while of Surf Test and Surf + Dye with CMT. Results also suggested that WSTD and Surf + Dye were equally associated with CMT in strength and direction as their counterpart tests WST and Surf Test with CMT and thus its response in efficacy to added dye was not distinct. Species effect on result scores was found negligible (P>0.05). The study further suggested that CMT was the most sensitive test, followed by WST/WSTD and Surf/Surf + Dye. Although, the five tests showed slight discrepancy in the trace category reaction, a strong relationship of Surf Test to CMT, its low cost, easy availability and readily adoptable qualities should spur the relevant authorities to recommend the use of Surf test as a routine practice in dairy farming and add this test in the curriculum of diploma and degree programmes.