Somatic Cell Counts of Cows with Recurrent Cases of Clinical Mastitis

Introduction Mastitis continues to be the most frequent and costly disease of dairy cattle. Financial losses due to mastitis occur for both subclinical and clinical stages of the disease. Losses caused by subclinical mastitis are well documented. Each doubling of SCC above 50,000 cells/ml results in a loss of 0.4 kg and 0.6 kg of milk per day in first lactation and older cows, respectively (Hortet and Seegers, 1998). Losses caused by clinical mastitis include discarded milk, transient reductions in milk yield and premature culling (Fetrow, 2000). Perceived financial losses for clinical mastitis vary widely. In 2002-2003, farmers participating in milk quality programs in Wisconsin (n = 117) estimated that each clinical case of mastitis cost approximately $97.00 USD, but estimates ranged from zero to $260 per case. Discarded milk accounted for more than half of the cost ($54.00 USD).