BVD control and eradication 

Bovine Viral Diarrhoea (BVD) is a highly contagious disease of beef and dairy cattle. Endemic (ever present) within the UK for many decades, an estimated 90% of herds having been exposed to BVD.  Despite the name, diarrhoea is not always a feature, but effects on fertility (abortions, stillbirths, reduced conception rates), reduced immunity (allowing pneumonia and scour to take hold) and production (reducing growth rates and milk yields) have severe economic and animal welfare impacts. BVD has no known human health or food safety implications. 

BVD transmission 

The virus is found in bodily fluids i.e. saliva, urine, faeces, semen and nasal discharges, so any close (“nose-to-nose”) contact can transmit infection, as can clothing and equipment. BVD virus has been detected in deer and is related to Border Disease in sheep, however these species are not considered a significant risk to cattle. 

After infection, adult cattle may display lethargy, fever, abortion and milk drop, or show signs of secondary infections e.g. pneumonia but most will recover and develop some immunity to BVD. However, when a cow with no immunity to BVD is exposed to the virus during pregnancy, her calf may be aborted or stillborn, or may be born apparently healthy but silently carrying BVD. This is the persistently infected (PI) calf. 

The PI calf 

These “super shedders” of BVD may be small and ill thriven but are often visibly undetectable and can become breeding adults, continuing to shed large volumes of virus throughout their lives. PI’s are the most significant source of BVD spread and the key to eradication.  

Is national BVD eradication feasible? 

Younger generations will not remember the success of UK Brucellosis eradication, and current experiences with bovine tuberculosis (bTB) and Bluetongue would understandably have livestock keepers feeling weary at the thought of taking on another challenge.  

Fortunately, unlike Bluetongue and bTB, several aspects of BVD make eradication an achievable goal. 

In 2006, Norway achieved BVD eradication after a 13-year campaign, so, if it’s both feasible and desirable, when do we start eradication in the UK? Would you be surprised if I said 25 years ago? 

Orkney 

With around 28,000 breeding cattle across 550 farms, Orkney has the highest density of beef cattle in Europe. In 2001, a voluntary eradication campaign began which removed 378 PI animals within 2 years. 

Within 6 years, over 80% of Orkney’s herds were BVD accredited (i.e. had 2 consecutive annual clear herd tests) and the islands were weaning an additional 1500-2000 cattle annually – an average of 3-4 extra calves per farm.   

Supported subsequently by mandatory testing throughout Scotland, Orkney removed the last BVD infected animal in March 2020 and was declared officially BVD free 2 years later.  

Biosecurity and surveillance efforts continue to protect this fantastic achievement, which undoubtedly represents a successful eradication program and sets the template for the rest of the UK. 

Scotland 

Many Scottish breeding herds had already achieved BVD accreditation through CHeCS health schemes, but in 2010 a phased eradication programme began which, at the time of writing, has recently entered phase 6. 

Beginning with a short period of subsidised testing, followed by mandatory screening of breeding herds, each phase has gradually tightened the net on BVD. Movement restrictions were introduced from 2014, testing arrivals from out with Scotland from 2015, and in 2019 a PI locator tool became available. By the end of 2019, 90% of Scottish breeding herds were BVD negative. 

Recently, controls have extended to include non-breeding herds and 2026 will add further measures as Scotland seeks to eradicate BVD entirely. If all Scottish herds were BVD negative, it is estimated that national farm income would be increased by £2.4 million annually. 

Northern Ireland, Republic of Ireland and Wales  

These nations have followed similar patterns to Scotland, initially supporting voluntary testing before introducing compulsory testing and thereafter, control measures such as movement restrictions on untested or BVD positive farms. Eradication programmes in Germany and France began in 2011 and 2019 respectively. 

What about England?  

England has run voluntary schemes for almost 10 years, but compulsory testing will finally begin in 2027. It is likely that movement restrictions will be in place early on and, having seen firsthand the challenges caused by unexpectedly finding BVD, my advice to cattle keepers in England would be, don’t wait for 2027! Make a start today. 

Why is testing becoming mandatory? 

None of us particularly likes being told how to do our jobs and, given the current pressures on UK farm animal health and finances, it is understandable that we may resent having to pay to look for more bad news! But BVD eradication is a huge opportunity for all UK cattle keepers to take back some control and boost our farm and national herd health and productivity going forwards.  

Costs of testing are often offset by the gains in health and productivity. AHDB estimates on average £3 return per £1 spent on eradication within a herd. As Orkney demonstrated, huge gains can be made through voluntary actions, but complete eradication only succeeds if everyone is on board. This requires mandatory testing and controls.  

What do I need to do? 

In Scotland, Wales or Northern Ireland you’re likely already familiar with BVD testing, but if your herd is recently established or significantly changed, your vet will be happy to advise on how to gain a recognised herd BVD status.  

Whilst England remains in the voluntary phase, I’d strongly recommend taking advantage of funding through the Animal Health and Welfare Pathway (which will stop when testing becomes mandatory) and making a start on BVD today. 

• Contact your vet. Make a herd specific control and eradication plan including testing, biosecurity and, if appropriate, vaccination.  

• Be aware that PI animals are not always as obvious as you might expect. I’ve seen a herd’s “best cow” or pedigree stock bull revealed as a PI so don’t assume you don’t have one.  

• Try not to worry about finding BVD on your holding. If it’s there, you have the most to gain from eradication. 

• If you do identify PI animals, isolate and remove them from the herd as soon as possible. Attempting to fatten PI’s is a false economy and will not be permitted once mandatory testing begins. 

• If your herd is BVD clear, protect it with strict biosecurity and consider vaccination (including bulls) before mating. 

• Remember, vaccinating a PI animal has no effect. That individual will continue shedding BVD and PI cows will always produce a PI calf. Vaccination can aid control, but eradication is only possibly by removing PI’s.  

• If you sell breeding animals, consider whether CHeCS scheme accreditation may be attractive to buyers. 

• Ensure robust biosecurity, avoiding close contact with neighbouring stock and cleaning equipment and clothing.  

• Test purchased animals before they join the main herd. Until testing becomes mandatory, there is always a risk of PI animals being sold (unwittingly or otherwise). This applies to all stock including twin-on calves and foster cows – both, in my experience, a significant source of BVD into previously BVD-negative herds. 

• Beware of “Trojan cows” – those that are pregnant when they join the herd. They may themselves test negative but carry a PI calf, so it is vital that her calf is tested at birth and ideally isolated (with her) from the rest of the herd until a clear test result is obtained. 

Testing methods 

Different testing approaches will suit different herds depending on their size and setup. This may include ear tag testing, milk testing and blood sampling; looking for infection or detecting exposure to BVD.  

Small herds may find it simplest to apply a tissue testing ear tag (official or management tag) to every animal in the herd and continue testing every newborn calf to monitor the situation. Ear tissue testing tags punch a small piece of tissue into a pot at the back of the tag, which can simply be sent directly to the lab for testing.  

Herds near to calving may choose to test every newborn calf (including any that are stillborn or aborted) and, after calving, test any remaining animals that have not produced a calf (including heifers, bulls and barren cows). If a calf is not a PI, it’s mother can’t be either so the status of the breeding cow herd may be established in this way. 

Large herds may decide to screen the yearling calves, sampling 5 animals from each separately managed group. Testing for exposure to BVD may indicate if it is likely that there is a PI on the farm or not and further action can be planned from there. 

Milk testing is appropriate in some circumstance but usually tests a bulk sample (from multiple cows) rather than on an individual basis.  

Ultimately, there is no doubt that eradication of BVD will help us all and the most import action is to get involved now. Speak to your vet today and take control of BVD in your herd before it becomes mandatory. Whether you have 2 cows or 2000, you are part of something positive and achievable in the eradication of BVD from the UK.  

Further reading 

Control of BVD 

Animal Health and Welfare Pathway funding