Mastitis is the most costly and most welfare-significant disease in dairy farming, requiring comprehensive prevention programs to reduce its enormous welfare impact.
Mastitis causes significant acute welfare harm through the pain of inflamed udder tissue, the systemic illness associated with endotoxemia in severe E. coli mastitis, and the distress of being in pain during the twice-daily milking process. Chronic subclinical mastitis causes ongoing udder discomfort and immune activation. The welfare burden of mastitis in dairy herds is enormous: even at 30% annual incidence, a 100-cow herd has 30 mastitis cases per year, each causing days to weeks of discomfort. Prevention through teat hygiene, appropriate milking equipment function, dry cow management, and housing hygiene significantly reduces welfare harm more effectively than treatment alone. Transitioning to selective dry cow therapy reduces unnecessary antibiotic use while maintaining protection for cows at risk.