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Johne’s, housing and veterinary action

by
01 October 2016, at 1:00am

Richard Gard looks at current and planned future activity and the strategies being promoted to help farms control the disease.

MANY MATTERS ARE CHANGING IN THE COUNTRYSIDE and the potential impact of Brexit does not seem to be a particular topic of conversation locally. More a case of whatever will be will be. However, a relatively small planning change has led to increasing levels of mutterings. 

Farmers with redundant barns were given the right to convert them into dwellings. The use of the dwelling thereafter was not specified and holiday lets have arisen as well as properties sold, either finished or under development. This was seen as a bonanza for those farmers with outdated buildings. There was also no limitation on erecting a new barn to replace the redundant barn.

Money for the farmer and a home for others was the targeted policy. It appears that living next to a farm has not been found to be idyllic for some residents. The sign on a farm gate (top right) rather sums up the situation.

There appear to be a few unintended consequences with one disease control initiative. It is a little over a year ago that the National Johne’s Management Plan was launched and the response from farmers and veterinary practices has been very encouraging with 80% of dairy farmers in Great Britain engaging in “robust Johne’s management activities”, accessed by Sophie Throup on behalf of the delivery team.

The first phase of the programme is now over and an analysis of the participation data will be available at the end of the year.

Initial indications are that over 80% of the herds surveyed show evidence of infection with the majority of herds having fewer than 5% of high- risk cows, but a level of 20% is not unusual.

Although clinical cases are likely to be few, the impact of the infection on herd performance is increasingly being recognised. Establishing herd disease status is being promoted, with the strategy that the more frequent the testing the better the understanding of the disease. Slap bang in the middle of the strategy is the veterinary surgeon, but only veterinary surgeons who are certified.

Establishing facts and figures

Cartoon cows and drawings outline that 80% of Johne’s infections occur within the first month of life. The Johne’s Action lea et also explains that calves ingest faeces through contaminated bedding, udders, teats or on dirty buckets of colostrum or milk. Less commonly the disease can be acquired in the womb or in later life. 

The website www.actionjohnesuk.org encourages the farmer to engage with the farm vet to establish an ongoing strategy for the disease and its control. As various strategies are available it is recognised that the farmer needs the vet to review the technical information and agree the best way forward. One size does not t all.

Screening

Six strategies are promoted arising from disease screening. The “targeted cow screen” is assessed from blood or milk samples of cows with histories of poor yield, weight loss or high somatic cell counts. Bulk milk monitoring does not detect the early stages of infection.

From the results of repeated whole herd screens, whole herd individual samples, targeted cows and bulk milk ELISA the vet and the farmer commence a strategy. If the infection is absent, monitor and manage to keep the herd disease-free.

Risk and prevalence are key. Low R and P – manage the cows to prevent transmission from cow to calf. Higher P – increased testing, biosecurity and biocontainment. Low P but infected – utilise culling as well as other measures. High R and high P – do not breed herd replacements from infected cows.

Vaccination is available as a rebreak to engage with one of the strategies, but tests cannot differentiate between antibodies from diseased or vaccinated animals and so ongoing test assessment can be compromised. There are added complications with reading a TB test from vaccinated animals. It is easy to see why, once a farmer engages with Johne’s Action, the vet is an essential part of ongoing assessment and advice. 

There is a form that the vet and the farmer sign, which is forwarded to the farm milk purchaser, detailing the steps taken to recognise the disease and indicate the appropriate strategy being adopted. There is also a space for the farmer to state that “I do not know my Johne’s Disease herd status and I have not discussed disease risk with my vet”. The number of farmers completing this section is not yet available.

The list of participating organisations that support the initiative is impressive and great attention is anticipated to make sure the programme delivers accurately and effectively.

Training take-up

During the past year, over 120 veterinary surgeons have taken up training as a BCVA Accredited Veterinary Adviser. The training is open to all, not just BCVA members and the cost is minimal. Registration with the BCVA provides access to online modules and completion means the name of the vet is added to the accreditation list and shared with the National Johne’s Action Group.

The vet becomes a BAJVA (BCVA Accredited Johne’s Veterinary Adviser). In order to advise clients a vet has not needed the nominal, but this has changed as the programme moves into phase two.

The National Johne’s Management Plan steering group has been seeking views on the next phase, which runs from now until December 2019 and important changes have been agreed. Only BAJVA vets will be able to sign the disease status form to be given to the milk purchaser.

A target of 95% of national milk production is to be collected from farms of known Johne’s status, with a more centralised system to monitor disease prevalence and a uniform approach to sharing information and undertaking action.

The National Johne’s Management Plan is funded by the milk purchasers. Dairy UK and AHDB are prime movers and RAFT Solutions Ltd (www.raftsolutions.co.uk) is managing the delivery.

Gradually throughout 2017, the assessment of herds will be collated and disease status reappraised throughout the following two years. An increasing level of veterinary involvement is anticipated.