Equine thrush is a bacterial infection of the frog and sulci of the hoof causing foul-smelling necrosis and lameness, closely associated with poor management conditions and preventable through good husbandry.
Mild thrush may be asymptomatic, but advanced cases cause significant pain when the horse bears weight on the affected foot. The characteristic black discharge and penetrating odour indicate active tissue necrosis — a condition that is both painful and represents ongoing tissue damage. Horses kept in poor environmental conditions experience chronic low-grade thrush that impairs comfort and may affect performance subtly before causing obvious lameness. The condition is almost entirely preventable through basic husbandry: daily hoof picking removes the packed debris that creates anaerobic conditions; clean, dry bedding prevents the prolonged moisture that allows Fusobacterium to proliferate. Owner education and regular farriery are the most impactful welfare interventions.