Lameness is the third most significant welfare problem in sheep (after gastrointestinal parasitism and reproductive failure), affecting approximately 10% of sheep in UK flocks at any given time. Understanding the causes and implementing systematic management reduces both the incidence and severity of ovine lameness.
Footrot (caused by Dichelobacter nodosus interacting with Fusobacterium necrophorum) is the most common cause of severe sheep lameness. It begins as foot scald — infection of the interdigital skin — and progresses to underrunning of the horn as D. nodosus produces proteases that digest horn tissue. Severely affected sheep are acutely and chronically lame, lose body condition, and have significantly impaired welfare. Footrot spreads readily between animals in wet conditions (wet soil and grass softens horn and maintains bacterial survival).
CODD, caused by treponemes (similar to those causing bovine digital dermatitis), was first identified in UK sheep in 1997 and has spread extensively. It causes distinctive ulcerative lesions at the skin-horn junction, with severe separation of the wall and underrunning of the horn. CODD causes intense acute pain — affected sheep may bear no weight on affected feet. It is more resistant to treatment than conventional footrot and requires aggressive antibiotic treatment and management measures for herd control.
Systematic lameness scoring — using validated 0-3 locomotion scoring scales applied at regular intervals (monthly minimum, more frequently in high-risk periods) — identifies affected animals requiring treatment. Scoring from a distance (watching sheep move without disturbance) provides welfare information without the additional stress of individual handling. Tracking lameness prevalence over time measures the effectiveness of management interventions and enables benchmarking against industry standards (target <5% lame).
Treatment of lame sheep should be: Prompt — treating within 3 days of becoming lame significantly improves cure rates (sheep treated early have 80%+ cure rates; treatment delayed to >7 days reduces success substantially); Appropriate — correct diagnosis determines correct treatment (CODD requires antibiotics; sole abscesses require drainage; foot scald may respond to foot bathing); Pain-relieving — NSAID administration improves welfare and treatment outcomes; Recorded — treatment records enable assessment of herd management effectiveness.
Footbathing with zinc sulphate (10%) or formalin (3-5% — increasingly restricted due to health and safety concerns) is used for treatment of foot scald and footrot prevention. Effective footbathing requires: appropriate concentration, adequate bath length and depth, sufficient contact time, clean bath solution (replace when contaminated), and appropriate timing (after driving sheep through — not at entry). Footbathing is an adjunct to individual treatment, not a substitute for prompt treatment of lame individuals.
Prevention of ovine lameness requires an integrated approach: selecting low-risk replacement sheep (avoid introduction of CODD and footrot), biosecurity for incoming animals (quarantine + treatment), genetic selection for foot conformation and foot health (using EBVs for lameness traits where available), maintaining appropriate stocking density (reduces wet soil conditions favouring infection), ensuring adequate zinc nutrition, and vaccination against footrot (D. nodosus vaccine — effective for footrot reduction but not CODD). Eradication of footrot from closed flocks is achievable with systematic treatment and culling of persistently infected individuals.