G81-556 Using the California Mastitis Test (CMT) to Detect Subclinical Mastitis

Apparently healthy cows can harbor subclinical mastitis, which creates tremendous loss in milk production. This NebGuide offers a method for detecting this disease. The dairyman is generally aware of clinical mastitis because it can be seen as changes in the milk, swollen udder and other signs exhibited by the cow. Compared with subclinical mastitis, clinical mastitis is much less costly, is of short duration, tends to be an individual cow problem, and is detected without special tests. Unfortunately, the apparently healthy cow can harbor subclinical mastitis, which creates tremendous loss in milk production. A cow with subclinical mastitis does not have a swollen, painful udder or abnormal looking milk. Infection is present, however, creating an elevation of the somatic cell (white blood cells and epithelial cells) count in the milk. These unseen infections are detected by several methods, including the direct microscopic somatic cell count (DMSCC), the Wisconsin Mastitis Test (WMT), and the California Mastitis Test (CMT). The DMSCC and WMT are laboratory tests but, fortunately for dairymen, the CMT is a cowside test that can be a valuable tool, yielding rapid results