Somatic cell count as a decision tool for selective dry cow therapy in Italy

The application of selective dry cow therapy is one of the measures currently suggested to reduce the use of antibiotics in dairy herds. However, the application of selective dry cow therapy will have a profound impact on Italian dairy herds, very likely affecting both milk yield and quality. Identifying cows to be treated at drying off is crucial for farmers and health authorities, therefore it is necessary the definition of a consistent and certified procedure. This article reports the results of a study aiming to identify which SCC threshold would be the most appropriate to identify cows to be treated and the potential consequences of different selection protocols on udder health after calving under field condition. Last milk test record before drying off and the average of lactation milk test records were considered on a database including 45,682 cow from 709 herd. Five different threshold were considered (50,000; 100,000; 150,000; 200,000; and 250,000 cells/mL). The statistical analysis of the database and a rational evaluation of the results suggest to define thresholds of 100,000 cells/mL for primiparous cows and 200,000 cells/mL for pluriparous cows measured either before drying-off or as the average of all the milk tests of the lactation. The criteria proposed will be useful to manage herd health and, specifically, dry-cows in an efficient and sustainable way, decreasing the use of antimicrobials without increasing the risk of affecting milk yield and quality after calving.