Date of this Version



© 1990, The Board of Regents of the University of Nebraska on behalf of the University of Nebraska–Lincoln Extension. All rights reserved.


The ProStaph 1TMMastitis costs U.S. dairy producers almost two billion dollars per year in lost milk production and treatment costs.

Mastitis is the major health problem of dairy cattle. The actual lost income for each mastitis infection is more than $400. Over 70 percent of the economic loss in mastitis is due to lost milk production from subclinically infected cows (those without apparent symptoms).

Subclinical forms of mastitis may not be observed by the milkers or other individuals in the dairy operation. Since there may be little or no visible change in the udder or milk, a laboratory test is needed to identify infected animals. Since subclinical cows may not be observed as infected, these animals carry great potential to transmit disease and infection to healthy cattle and thus put the entire herd at risk. Test can identify cows which are infected with mastitis but have no visible symptoms. This NebGuide explains how to interpret and use the test.