Welcome to the Action Group on Johne's
The Action Group on Johne’s initiative called The National Johne’s Management Plan (NJMP) seeks to manage and then reduce the incidence of Johne’s disease on dairy farms in England, Wales and Scotland through implementation of one of the six control strategies, and monitored on each farm by BCVA Accredited Johne’s Veterinary Advisors.
New research confirms an association between SICCT and Johne’s antibody results
A study of 800,000 cows published in October 2022 demonstrates that conducting a Johne’s antibody test soon after a TB skin test (SICCT) can impact the Johne’s result. This result differs depending on whether the cow is infected with Johne’s.
In a Johne’s-infected cow (i.e. a J5 Red cow), there is an immediate increase in the Johne’s antibody result, indicating increased test sensitivity. In a non-infected cow (i.e. a cow that does not meet the J5 Red cow criteria), this increase is both significantly smaller and delayed peaking at 15–28 days after SICCT, indicating reduced test specificity.
While we now know that SICCT has an impact on Johne’s milk antibody results, further research is needed to determine how we should best use this information in the management of Johne’s disease.
There may be circumstances where it is beneficial to schedule your Johne’s test shortly after SICCT, but the following must be considered:
- To get the best advantage out of the increased test sensitivity, you should conduct your Johne’s test within 14 days of SICCT. If you test between 15–28 days after your SICCT, you may see an increase in false positives
- The impact in herds with <5% Johne’s prevalence is unclear. If you have a low-prevalence herd, take care when interpreting results
- We do not fully understand what a positive Johne’s result post-SICCT means compared with a standard positive. A positive result post-SICCT should be a prompt to manage the animal appropriately, not to cull her
Current recommendations to leave a minimum interval of 42 days (milk) and 90 days (blood) between a SICCT and Johne’s test remain and should be followed, unless directed otherwise by your veterinary surgeon.
Red Tractor Standards
Since October 2019 the Red Tractor dairy standards now include a requirement that all Red Tractor approved members have a signed NJMP declaration.
This website is designed to be an information portal on Johne’s, providing relevant technical documents and links that will aid Johne’s engagement and control. Please note that the Group is not in a position to advise farmers on their specific Johne’s control plans. These should be discussed with the farm vet.