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CMT is one of the most common diagnostic tests in detection of
sub clinical mastitis in dairy cows. In this test, there are four
degrees: tract 1, 2 and 3. Grade 3 CMT is equivalent to about 4 to
8 million scc/ml in milk. The previous reports have determined
that blood table especially WBC and Neutrophils are changed in
clinical mastitis caused by Escherchia coli, and Streptococcus
agalactiae, However, there was not such data for sub clinical
inastitis in the leaterature. In this study CMT was performed in 833
dairy cows belonged to 5 herds in the province suburb of Tehran.
Milk samples were taken for culture from all quarters with grade 3
(DMT and 115 blood samples were randomly taken from 94 cows
with sub clinical mastitis (grade 3 CMT) and 21 cows without any
sign of disease and negative CMT. The results was statistically
tested using ANOVA test. There were no significant correlation
between sub clinical mastitis and changes in WBC/Neutrophils.