Quarter milk bacteriology results of samples
collected within the first week of calving were
used to calculate the test characteristics of the
California Mastitis Test (CMT) that estimate the
udder health status of fresh dairy cows. Over
1,200 quarters were both cultured and had a
CMT performed. The overall sensitivity and
specificity of the CMT was 68.8% and 71.5%,
respectively. Using a cutpoint of any CMT
reaction as a positive test and examining the
results by various days in milk, the highest
sensitivity and specificity occurred at day four
(82.4% and 80.6%, respectively). The CMT has
the potential to be a useful tool for monitoring
udder health in fresh cows.
