The CHECS board have announced changes to the CHECS Johne’s programme that are due to come into effect from 1st July 2021. The changes mean that follow up testing using dung samples will no longer be allowed if more than 2% of animals test positive on blood samples at the annual herd test. This is a change from the current rules, which allow follow up dung testing regardless of the number of blood positives. Dung testing shows whether an animal is shedding MAP, the agent that causes Johne’s disease; it does not confirm if the animal is infected or not. Animals which test blood positive and dung negative are likely to be incubating disease, which is why the current CHECS rules stipulate that these cannot be sold as breeding animals. The new rules will extend this stipulation to include the calves of blood positive animals. Follow up blood testing of blood positive animals will still be permitted to help to identify false positive results.
Bovine tuberculosis (bTB) and bTB testing and exposure to other mycobacteria can cause cross-reactivity with the Johne’s blood test. The dung test is specific for the Johne’s organism; there is no cross-reactivity with the dung test. The CHECS board have yet to clarify whether there will be any exemption from the new 2% rule for herds that have recently had a bTB test. With the introduction of the new rule, it is anticipated that some herds may fall from having risk level 1 or 2 status and others may not be able to progress beyond level 3 or 4 due to the issue of cross reactivity and the removal of the ability to follow up with dung testing. A revision of the technical document detailing these changes has not yet been produced although CHECS have given assurance that this will be available after 01 June 2021.
Why not keep it as it was as it was working at reducing johnes on many hard working farms. Farms that are benefiting from the higher health from doing such tests. Could they not have come up with another level say “level 1* ” for farms that have had consecutive years of negative blood results without any dung samples needed . So level1*¹ for 1st year clear with no dung then level1*² for having two years clear on bloods only and so on. Johnes is such a hard disease to get rid of and takes years to get any where with. To take all the hard work and the cost for doing these tests it feels like a good kick in the teeth if they go ahead with this plan.
Dear David,
Thank you for your comment and concern about the change in CHECS rules. The rule change has been decided by the CHECS board against the strong advice of 2 of the 3 cattle health schemes that accredit significant numbers of cattle in the UK. We believe this change will have significant negative consequences on members and fails to recognise the substantial issue of false positive Johne’s blood and milk tests due to cross reactions with related bacteria. While it will mean that Level 1 status will provide greater assurance to buyers, it will also mean that many herds with little or no Johne’s will not be able to rise above Level 4 or Level 3 due to the cross reaction issue. This may be a substantial disincentive to continue testing as part of a CHECS programme. We would suggest that you take any concerns you have to your breed society who will be able to take them to the CHECS board as a matter of urgency.
Kind regards,
Paul Burr
Director