Ovine and Caprine Footrot Study Guide

Overview and Clinical Importance

Footrot is a highly contagious, debilitating bacterial disease affecting the interdigital skin and hoof matrix of sheep and goats. It is one of the most economically significant diseases in small ruminant production worldwide, causing substantial losses due to reduced weight gain, decreased wool and milk production, lameness-associated reproductive failure, treatment costs, and premature culling. Over 90% of lameness cases in sheep are attributed to footrot.

Footrot represents a major animal welfare concern due to the severe pain and chronic suffering it causes. The disease is caused by a synergistic infection requiring two anaerobic bacteria: Dichelobacter nodosus (primary causative agent) and Fusobacterium necrophorum (secondary invader). Understanding the pathogenesis, clinical presentation, diagnosis, and treatment options is essential for the NAVLE.

Etiology

Primary Causative Agent: Dichelobacter nodosus

Dichelobacter nodosus is a large, Gram-negative, anaerobic rod (0.6-0.8 µm wide by 3-10 µm long) with rounded ends that may have terminal swellings, giving it a characteristic "barbell" appearance on Gram stain. It belongs to the family Cardiobacteriaceae and is an obligate pathogen of the hoof.