SOTA: Treatment of Subclinical Mastitis

Subclinical mastitis occurs when intramammary infection results in an inflammatory response that is recognized only by use of a diagnostic test such as enumeration of somatic cells in milk.  Milk from cow affected with subclinical mastitis can be sold for human consumption as long as it is diluted with milk from healthy cows.  Thus, treatment during lactation is generally not recommended due to considerable economic losses related to discard of saleable milk.  For decades, use of longer acting intramammary antimicrobials given at dry off has been the basis of treatment of subclinical mastitis.  As concerns about antimicrobial resistance have increased, reducing unnecessary antimicrobial suage in animal agriculture has become a priority.  This session will review etiologies and presentation of subclinical mastitis in dairy cows and present evidence about when and how to implement selective treatment protocols at dry off.