Caseous lymphadenitis (CL) is a chronic bacterial disease causing abscessing of lymph nodes in sheep and goats, reducing welfare through ongoing infection, weight loss, and in internal forms, organ damage.
CL causes welfare harm that is often underappreciated because affected animals may appear relatively normal despite chronic infection. External abscesses cause localised discomfort, especially during rupture; the cheesy caseous pus released is infectious and causes pain at the site. Animals with internal CL suffer more significantly — respiratory compromise from mediastinal abscess enlargement, weight loss from chronic infection, and eventually organ failure in severe cases. The chronic nature of the disease means that welfare harm accumulates over months to years rather than presenting as acute crisis. A welfare-focused approach to CL management combines vaccination to prevent new cases, prompt culling of heavily affected animals to reduce their ongoing welfare deterioration, and strict biosecurity to prevent farm-to-farm spread.