Assessing the Risk of Subclinical Infections in Cows with Clinical Mastitis

摘要

Clinical mastitis (CM) is an expensive disease, with an estimated cost of $400 (Rollin, 2015) per case. A common approach to treatment and management of cows with CM is to focus efforts on the quarter(s) with abnormal milk and signs of inflammation, disregarding quarters with visibly normal milk. Current recommendations for pathogen based mastitis treatment protocols result in a decrease in antibiotic use and increase in saleable milk. However, when we compare the estimated percentages of CM (Barkema, 1998) to all infected quarters in a herd (Eberhart, et al, 1982) based on bulk tank SCC, we observe that CM infections can be "the tip of the iceberg." Subclinical mastitis (SCM) can negatively impact milk quality and production (Huijps, et al., 2008)and may go undiagnosed in cows with clinically normal quarters. Previous research has reported that 67% of cows with CM also had SCM in a nonclinical quarter (Lago and Silva-del-Rio, 2014). This research continued to report that sampling nonclinical quarters increased the percentage of cows with identifiable intramammary pathogens from 52% to 82%.