Ovine lameness in Ireland: a survey-based investigation of farmer reported prevalence, recognition, and treatment of lameness conditions

Abstract

Background: Ovine lameness represents a significant production and welfare challenge to farmers and comprises two main categories, infectious and non-infectious lameness. The leading infectious lameness conditions are interdigital dermatitis (ID), footrot (FR) and contagious ovine digital dermatitis (CODD). The predominant types of non-infectious foot conditions include toe granulomas (TG) and shelly hoof (white line disease; SH). There is a paucity of information available as to how Irish farmers treat infectious foot lesions in sheep. This study aimed to i) Establish farmer-reported prevalence of lameness in Irish sheep flocks, ii) Assess farmers’ ability to identify infectious and non-infectious lameness types, iii) Examine the treatment methods employed by farmers for managing and treating infectious lameness in sheep. Results: The survey was conducted opportunistically and non-randomly. Three hundred and sixty-three valid responses were gathered. The median overall farm lameness prevalence reported was 6.0% (IQR: 4.0%–10.0%). Respondents reported ID as the most common lameness condition with a median estimated prevalence of 10.0% (IQR: 4.0 – 15.0). Respondents identified 77.9%, 76.6%, 61.7%, 67.3% and 67.0% of ID, FR, CODD, TG and SH lesions correctly, respectively. Where the respective lesion was correctly identified 95.1%, 90.2%, 49.2%, 59.7% and 68.4% reported to have seen ID, FR, CODD, TG and SH lesions, respectively on their farm previously. Antibiotic aerosol was the most frequently utilised treatment for ID (71.3% [95% CI:65.2, 76.8%]) reported by survey respondents. Antibiotic injection was reported by respondents as the most used treatment for FR (72.2% [95% CI: 65.8,78.0%]) and CODD (85.1% [95% CI: 75.8, 91.8%]). Therapeutic foot trimming was practiced by 52.9% (95% CI:46.1,59.6%) of respondents for the treatment of FR. Conclusions: Interdigital dermatitis (ID) posed the greatest burden to Irish farmers, with a median farm prevalence of 10.0%, while footrot affected 90.2% of flocks (median 4.0%). Contagious ovine digital dermatitis, previously considered rare, was reported in 47% of flocks (median 3%). Farmers’ ability to correctly identify lesions varied from 79.9% for ID to 62.4% for CODD. Therapeutic foot-trimming, remain widely used within Irish flocks and was reported by 52.9% of respondents for the treatment of FR.