Evaluating the ability of quarter and cow-level somatic cell count to diagnose intramammary infections with non-aureus staphylococci (NAS) and Corynebacterium species
The ability to readily and dependably identify high cell-count quarters in dairy cattle that may have intramammary infections is key before any steps can be made to improve bulk-tank milk (BTSCC) quality. Prior work evaluating quarter-level somatic cell count (SCC) showed it can be a poor predictor of intramammary infection (IMI), but this work focused on a high SCC herd and broad categories of pathogens. The objective of this project is to establish how well quarterand cow-level SCC corresponds to culture data for diagnosis of IMI in 10 herds with a low BTSCC, specifically evaluating 2 minor mastitis pathogens of increasing importance, non-aureus staphylococci (NAS) and Corynebacterium species. We will also explore if either composite or quarter SCC before and after sampling dates may predict a change in IMI status.