Mud fever (pastern dermatitis) is a painful skin condition caused by Dermatophilus congolensis and other organisms in wet muddy conditions, causing welfare suffering that is largely preventable through paddock management.
Mud fever causes pain from skin inflammation, ulceration, and deep tissue infection that is worst when scabs are removed during treatment. Horses with active mud fever are often reluctant to have their legs handled and may show lameness from swelling and pain below the fetlock. The condition is largely preventable through paddock management that reduces prolonged contact with wet ground, and through regular leg inspection that allows early treatment before deep infection establishes. Leaving mud fever untreated because treatment is uncomfortable is a welfare failure — the condition worsens progressively without management. Providing dry standing areas in paddocks, particularly through winter, is the most welfare-effective paddock management intervention.