What is the treatment protocol for contagious ovine foot rot caused by Dichelobacter nodosus?

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The core treatment protocol for ovine footrot combines careful claw trimming, footbathing with zinc sulphate, and isolation or culling of non-responders, with complete elimination of virulent Dichelobacter nodosus achievable in 6–19 weeks. 3 Claw trimming is the essential first step before any topical treatment. Loose and severely overgrown horn must be carefully removed prior to footbathing or spray application; trimming without causing bleeding is the recommended technique. 23 Trimming instruments are a significant transmission vector — knives, hands, and removed horn material all test positive for viable D. nodosus after use, so wiping the knife with a disinfection towel and wearing and changing gloves after every sheep is required to prevent iatrogenic spread. 4 Footbathing with 10% zinc sulphate is the primary flock-level treatment. The established protocol is weekly stand-in footbaths for 10 minutes per sheep. 3 This regimen achieved 100% elimination of virulent D. nodosus (aprV2) across all 28 treated flocks, with time to elimination ranging from 6 to 19 weeks depending on within-flock prevalence at the start of treatment. 3 Weekly walkthrough zinc sulphate footbathing restricts footrot prevalence to 2% (97% effective) compared with 76% in untreated animals; footbathing every 3 weeks with a 1-hour stand-in Footrite® protocol achieves 6.5% prevalence (91% effective), which is significantly less effective than weekly bathing. 5 Glutaraldehyde-based footbaths (2% Digicur) are ineffective at reducing D. nodosus load when applied as a one-off or weekly footbath and are not recommended as a primary treatment. 6 An antibiotic-free hoof spray (Intra Repiderma) is a validated alternative to footbathing, particularly for small flocks where footbathing is logistically impractical. The protocol begins with claw trimming at the first visit, followed by spray application three times within the first week, then continued until all sheep in the flock test PCR-negative for vi