Johne’s disease in Irish dairy herds: considerations for an effective national control programme

Abstract

The Irish dairy industry has established a reputation for the production of safe and healthy dairy products and is seeking to further expand its export market for high value dairy products. To support its reputation, stakeholders aim to control Johne's disease. To assist decision-makers determine the most appropriate design for an Irish programme, a narrative review of the scientific literature on the epidemiology of Johne's disease, and selected control programmes throughout the world was undertaken. Two modelling studies specifically commissioned by Animal Health Ireland to assess testing methods used to demonstrate confidence of freedom in herds and to evaluate a range of possible surveillance strategies provided additional information. The majority of control programmes tend to be voluntary, because of the unique epidemiology of Johne's disease and limited support for traditional regulatory approaches. While acknowledging that test performance and sub-clinical sero-negative shedders contributes to the spread of infection, a range of socio-political issues also exist that influence programme activities. The paper provides a rationale for the inclusion of a Veterinary Risk Assessment and Management Plan (VRAMP), including voluntary whole herd testing to identify infected herds and to support assurance-based trading through repeated rounds of negative testing, national surveillance for herd-level case-detection, and improved understanding of biosecurity management practices. Identification and promotion of drivers for industry and producer engagement in Ireland is likely to guide the future evolution of the Irish Johne's Control Programme (IJCP) and further enhance its success. The provision of training, education and extension activities may encourage farmers to adopt relevant farm management practices and help them recognize that they are ultimately responsible for their herd's health and biosecurity.

The Irish Johne's Control Programme

“…This case study describes the implementation of a control programme for Johne's disease (JD, paratuberculosis) in Ireland based on recommendations of Jordan et al ( 1 ), some issues that arose during the initial stages of the programme, and ways in which these could be managed as the programme matures.…”

“…To ensure the relevance and technical robustness of a future Irish Johne's Control Programme (IJCP), AHI commissioned an evaluation of testing strategies to determine the most appropriate approach ( 15 ) and a review of alternative surveillance methods for a national programme ( 16 ). A third paper ( 1 ) considered the elements required to effectively address the objectives of an Irish national control programme.…”

Alternatives to antibiotics in veterinary medicine: considerations for the management of Johne's disease

“…As a result of more targeted efforts at reducing the impact of JD, test-based culling has become the standard, with newly bought calves and heifers undergoing testing for MAP infection. A negative result allows the new purchase to be integrated into the wider herd, while a positive result leads to culling (Jordan et al ., 2020). An inherent issue with test-and-cull methods is that no testing method is both 100% specific and 100% sensitive and existing programs are expensive and limited by the ability of farmers and veterinarians to recognize JD (Windsor and Whittington, 2010).…”

Ruminant health research – progress to date and future prospects, with an emphasis on Irish research

“…The IJCP is a voluntary national programme and is managed by AHI under the guidance of the JD IG (Animal Health Ireland, 2021c). The objectives of the programme are addressed through a combination of risk assessment, voluntary assurance and national surveillance (Jordan et al, 2020). The IJCP enables participating herd owners to have increasing confidence in the absence of infection in their herds and to achieve significant control or elimination, and it underpins the quality of Irish dairy and beef produce in the international marketplace.…”