Compulsory testing is critical to managing bovine viral diarrhoea

Approaches to tackling bovine viral diarrhoea (BVD) might differ across the devolved nations, but without compulsory testing across the UK, the dairy sector risks going backwards in its efforts to managing the disease. 

Rarely a month goes by where BVD isn’t a topic of conversation in our practice. Endemic in the UK, BVD causes immunosuppression, abortion, and infertility, leading to secondary diseases that further impact fertility and productivity.

The resulting financial losses in cattle herds are significant – estimated to be up to £66 million across the UK each year.

While cattle can be vaccinated against BVD — and vaccination uptake is generally good across the UK — when it comes to controlling and eradicating the virus the focus must be on understanding the risks of transmission, as well as identifying its presence in a herd.

Removing persistently infected cattle, which act as a reservoir of infection, is central to eradication schemes.

With no single, unified system of surveillance and eradication in the UK, we risk going round in circles without progress towards the end goal of a BVD-free nation.

Multiple approaches

Efforts to manage BVD have fallen to the devolved governments, with each nation adopting a different approach.

Northern Ireland has a compulsory scheme, with all calves born since 2016 tested for BVD using an ear tag.

After a period of voluntary testing, Scotland also introduced a compulsory scheme in 2013. There, the process allows an annual antibody screening of 5 to 10 youngstock via blood tests, which identify whether the disease is present on the farm. More recently, movement restrictions have been placed on herds where BVD is present, and the disease status of farms is publicly available.

In England and Wales, meanwhile, farmer engagement in BVD surveillance and eradication has been done entirely through voluntary schemes.

Under England’s Stamp it Out scheme, which ran for three years until summer 2021, vets were paid to visit farmers to talk to them about BVD, and the reasons why it’s an important disease to combat. As well as assessing the disease risks on farm, vets also performed blood and milk sampling.

Herds found not to have BVD received a follow-up advisory visit, where vets helped to create an action plan to keep it off the farm, while if a herd tested positive funding towards diagnostic testing was offered. The Welsh Government took a similar route by paying for optional annual blood tests; similar to England, additional budget was available for further testing if the disease was found.

Compulsory measures

With awareness of the risks of BVD rising and disease rates dropping, these schemes have undoubtedly had success. In Scotland, for example, about 90% of breeding herds are now BVD-negative.

However, without compulsory testing in each devolved nation, it’s hard to know if eradication can be achieved across the UK.

Farmers are never fans of compulsory schemes, but if you speak to Scottish producers, they’ll tell you that taking a compulsory approach has meant testing has become a simple procedure that becomes routine, like regular TB testing.

Similarly, with ear tagging in Ireland, it’s not deemed a particularly onerous procedure, and farmers just get it done.

For England and Wales, however, while several thousand farmers have been engaged in voluntary testing (in England the goal was to reach 8,000 dairy farmers, a figure that wasn’t quite reached due to the pandemic), the big question is what happens now those initial schemes have ended.

Even more important is those farmers who showed no interest in having free diagnostic tests while they were being offered.

In Wales, the government has decided to extend its initial testing scheme for three more years, but in England no more funding has been made available for additional BVD testing since the Stamp it Out scheme ended.

Some producers on aligned contracts have been contractually obliged to continue with surveillance, but a lot of other producers are wondering why they now need to pay for testing for a disease they haven’t got.

My concern is that this has resulted in England taking a step backwards, with farms that were engaged with the funded programme potentially falling off the testing and surveillance radar.

Being prepared

For the farmers who have decided to continue with testing, they have had to continue to bear the financial burden, as well as being organised enough to schedule testing of eligible animals.

Sampling for BVD antibodies requires a specific cohort of animals; you ideally want home-bred cattle between 9 and 12 months, you want them to be unvaccinated, and they need to have been mixed with the herd to give an indicator of exposure.

As the uptake of BVD vaccination is very high in some areas, only a limited time in the calendar exists when farmers will have unvaccinated animals at the right age. This means practices have to be incredibly organised in terms of knowing their farmers’ schedules and booking testing dates to hit that window.

Thanks to staff shortages and COVID-19, that’s been tricky, and as a result I think the industry has fallen behind in the progress we had been making in those schemes.

Potential turning point

Looking ahead, the agricultural reforms in England and the end of the Single Farm Payment (SFP) could offer an opportunity to make a difference to the way BVD is monitored and controlled.

One of the tranches of money set to replace the SFP is wrapped up in the Animal Health and Welfare Pathway (AHWP), an industry and government partnership being introduced under the Sustainable Farming Incentive that will see farm vets working with farms to cover their health and welfare needs.

From what we’ve heard so far — and admittedly that’s been quite limited — it seems farmers will be paid to have an annual vet visit, to include data collection and welfare assessments.

Crucially, as part of that, a lot of talk has been about centrally funded testing for endemic diseases, which will include BVD on cattle holdings.This could mean more producers are reached, as all farmers eligible for farm subsidies will be eligible for a vet visit, but ultimately the scheme will still be voluntary.

BVD testing will be driven by veterinary advice, so uptake will require the backing of vets across England.

Supporting producers

Our own practice, LLM Farm Vets, has committed to helping dairy producers keep an eye on BVD in their herds through our own scheme.

Launched about five years ago, our Infectious Disease Check is free to farmers, and involves a quarterly bulk tank antibody test done for a range of infectious diseases, including leptospirosis, infectious bovine rhinotracheitis, fluke and Salmonella.

We also test 20 or 30 sentinel farms for Schmallenberg disease, and in the past year we have added BVD PCR tests, so that we’re testing for the BVD virus every six months and antibodies every three months.

It’s a fully automated system; when milk is sent to the processor, they automatically take a sample and test it at an accredited milk lab.

Taking milk samples is much easier than taking blood samples from heifers, and it gives us an early warning of whether the disease is on the farm, and if so, we can look at the farm in more detail.

We’ve also been doing our very best to keep those farms on annual blood testing, to help them maintain their BVD-free status.

Looking ahead

Ever since the end of the national schemes in England and Wales, as a practice we’ve been telling our farmers to ready themselves for compulsory testing at some stage.

If the AHWP is going to be a turning point in eradicating BVD in England, the scheme needs to have compulsory testing as a logical next step. Given that testing is compulsory in Scotland and Northern Ireland, it makes sense that it would eventually be made compulsory across the rest of the UK, too — particularly as Scotland and Northern Ireland are important trading partners.

Long-term, I hope farmers will see it as a badge of honour to have BVD-free herds, and perhaps having that status could even lead to financial benefits when selling animals.

Ultimately, though, the industry has to focus on BVD being a treatable problem, and not just an endemic disease it needs to live with. BVD is possible to eradicate, we just need the right schemes in place to support the industry to do just that.