Utilising on-farm risk assessment data for the management of Johne’s disease in dairy cattle in Northern Ireland

Johne’s disease (JD) causes weight loss, diarrhoea, and reduced milk yields in clinically infected cattle. In 2020, Animal Health and Welfare Northern Ireland (AHWNI) launched a voluntary JD control programme (JDCP) which focuses on bio-exclusion, biocontainment and market reassurance. Authorised veterinary practitioners (AVPs) conduct a Veterinary Risk Assessment and Management Plan (VRAMP) and use this information to make up to three recommendations. Between August 2022 and January 2024, 2274 herds enrolled in the NI JDCP and conducted up to three VRAMPs. This study characterised the JD-related risks and veterinary recommendations, identified the risks related to confirmed cases of JD and assessed if farmers changed their practices in response to AVP recommendations. AVPs assigned risk scores to management practices. Practices related to the calving area, particularly an absence of or delayed snatch calving, demonstrated the highest average risk score. Thematic analysis highlighted five main themes within AVP recommendations, including the use of diagnostic testing and management of calving areas. Multivariable binomial logistic regression identified five management practices which significantly increased the likelihood of herds having had a confirmed case of JD, including the segregation of clinically infected or test-positive cows from the rest of the herd in the calving area. Analysis of the risk scores and responses to closed questions from 278 herds which conducted first and second VRAMPs suggested that farmers had not changed their JD-related management practices in response to AVP recommendations. These findings simultaneously outline the challenges in JD control, reinforce the use of VRAMPs in identifying JD-related risks, demonstrate the harmonisation in AVP recommendation themes and provide data which can be considered by industry and policy makers.