The most common and costly disease in dairy cattle — and a major welfare problem
Mastitis — infection and inflammation of the udder — is the most common and economically costly disease in dairy cattle worldwide. It causes significant animal suffering ranging from mild discomfort (subclinical mastitis) to severe systemic illness and death (toxic mastitis). Despite decades of research, mastitis remains a major welfare challenge in intensive dairy production, with prevalence remaining stubbornly high in many systems.
Mastitis causes pain through multiple mechanisms: tissue inflammation, increased intra-udder pressure, systemic endotoxemia in severe cases, and physical manipulation during treatment. Pain assessment using behavioral and physiological indicators confirms that clinical mastitis is painful — cows with mastitis show altered gait, reduced activity, reduced feed intake, and elevated pain biomarkers. Despite this, analgesic use in mastitis remains inconsistent globally.