Cumbria farmers challenged to be first county to oust BVD
© Tim Scrivener Cumbrian cattle farmers are being urged to sign up to a scheme to eradicate bovine viral diarrhoea (BVD) from their herds and make Cumbria the first county in the country to eliminate the costly virus.
It is believed that Cumbria could be one of the most relevant counties for BVD control as it contains the highest concentration of cattle in the country.
It also borders on to Scotland, where a BVD eradication programme is already four years into action.
See also: BVD forum: Joint approach needed to tackle disease
Vet David Black, Paragon Veterinary Group, Cumbria, said: “Cumbria is the right county to set an example. Wouldn’t it be fantastic to be the first county to be BVD free?”
The scheme, which was launched in July last year, has set a target to try to eradicate the virus from herds in England by 2022. Already 630 herds have registered on the scheme and 12,000 individual animal statuses are on the database.
How the scheme works
It is free to join and allows members to access the BVD status of tested animals and herds, and promote the BVD free status of their herd, once it has been achieved.
There will be a small cost to get results onto the database, ranging from 25p for antigen tests (tag and test and blood samples) to 50p for antibody blood samples.
The first step is for farmers to sign up to the scheme at the the BVDFree England website and then set up a programme on the farm (see box on how to set up a scheme on your farm).
Speaking at a BVDFree England meeting at Borderway Mart, Carlisle, last week (31 January), vets explained how easy it was to eradicate the virus, but stressed the importance of all farmers buying into the scheme.
Derek Armstrong from AHDB Dairy said: “It’s about developing the next generation of cattle for the next generation of farmers.
“This disease is relatively easy to eradicate as Persistently Infected (PI) calves are an Achilles’ heel. If you can find PI calves you can free the herd of BVD.”
Farmers tempted to keep PI calves to fatten them were warned of the dangers.
Mr Armstrong added: “If you try to fatten you will lose more money due to the effect on the rest of the herd. A lot of the cost come from the effects on fertility.”
Buying in cattle
All vet speakers talked about the dangers of buying in cattle and agreed it was one of the main routes to introducing infection into a herd.
However, within the next two years a system will be in place whereby the BVD status of herds and animals will be displayed automatically at sales – with the Livestock Auctioneers’ Association already supporting the programme.
“You can already do it on your phone,” added Mr Armstrong. “You can log on to the BVDFree England website and input individual animals or holding numbers and it will give you a result for those registered.”
Symptoms of BVD
Non-Pregnant animals
- No symptoms
- More susceptible to other diseases and harder to get in calf
Calves
- More susceptible to other diseases and more likely to see more cases of pneumonia and scours
Pregnant cow
- Can reabsorb calf/abort
- Deformed calves
- Production of PI calves (if infected in first 120 days of pregnancy)
Persistently Infected (PI) Calf
- The persistent infection comes about because of infection of the calf in the womb during the first 120 days of pregnancy
- Infective for whole of lifetime
- In most cases never really grows and is always a poor doer
- Likely to die before 18 months old
- There are some exceptions where calves may do OK and these are the dangerous ones are they are infecting other animals
How to set up a scheme on your farm
Step 1 – Assess the herd
- Look at biosecurity, vaccination programme, disease history and disease risk
Step 2 – Define the herd status
If using antibody ELISA:
- Blood test 5-10 young stock from each management group (9-18 months of age)
- Bulk milk/first lactation cohort antibody samples
Or if using antigen ELISA or PCR:
- Tag and test all youngstock born for a minimum of two years
Step 3 – Action plan
If no PI animals are found then:
- Put an action plan in place to control risk of introducing BVD on to the farm
- Monitor progress
If active BVD is found then:
- Screen all PIs on the farm
- Test all animals and cull PIs
- Test all calves for one year after PIs removed and cull any new PIs
- Continue to test for a further 12 months of more PIs found
Step 4 – Monitor progress
- Keep defining herd status to retain BVD free herd status
- Test youngstock at 7-12 month intervals using antibody and/or quarterly bulk milk antibody
- Or continue to tag and test all youngstock
Case studies
Case study 1
- Dairy herd
- Initially tested BVD negative
- Bought two unvaccinated in-calf heifers into the herd
- When cows calved down the calves were picked up as PIs by tag and testing
Take-home message: When buying in in-calf animals there is no way of testing whether the calf is a PI, so you need to tag and test.
Case study 2
- Suckler herd
- Buys in cattle
- On BVD vaccination programme
- Did check test in 2012 and 2/10 cows tested antibody positive, which showed they had been exposed to BVD
- Farmer thought the reason for this was related to biosecurity, so opted to live with a ‘non negative status’
- In 2013 did another check test and found 8/10 animals BVD positive, so knew BVD was circulating in the herd
- Found four PIs on the farm and all died by two months of age
- Further investigation found possibly to have come from a cow bought in with calf at foot
- Wondered why vaccination wasn’t working and discovered the farm wasn’t always vaccinating stock twice – first vaccine and then booster – before they went to the bull
Take-home message: Make sure any cows bought in with calves at foot are isolated and calves tag and tested. Also, if using an older vaccine rather than the newer one-dose vaccine, make sure cattle are vaccinated twice and at the right time and in the correct time frame.
Case study 3
- Dairy farm – 300 cows
- Breeding own replacements, but not completely closed
- Vaccinating for BVD and bulk milk testing
- During routine PD session saw two heifers with calves smaller than the rest
- Turned out both calves were PIs
- Took group around the heifers and blood sampled
- Turns out mothers of the two PIs were not properly vaccinated before being recipients of embryos
Take-home message: Do not forget the heifers and make sure they receive correct dose and number of vaccines. Also, do not forget the bull. In addition, if testing bulk milk samples for BVD remember to repeat every three months as only cows on that day will be tested.
Case study 4
- Calf rearer
- Was rearing 15-20 calves and was sourcing from a single trusted source. Was selling Black and White bulls and Continentals at one year old
- Had good pneumonia vaccination plan in place and only ever got occasional case of pneumonia
- In 2016 wanted to increase number of calves to 100 at any one time, so sourced some calves from another dairy herd and soon after saw severe pneumonia outbreaks
- Lost 12 calves over a two-week period from severe pneumonia
- Vet assessed farm and made a few observations where the airflow was moving from older calves to younger. The stocking density was also quite high in the shed and a lot of the calves looked like poor doers
- The farm tag and tested the youngest group of calves for BVD and out of 20, three were PIs
Action plan
- The PIs were removed
- The farmer was advised to go back to sourcing from a single source and put an agreement in place that the dairy farmer tag and tested calves and also vaccinated for pneumonia before going to the calf rearer
Take home message: Only purchase tag and tested calves, even if that means paying an extra £5 for the calf to cover the cost of the tag and test. Dairy farmers advised not just to test their heifers, but also their bull calves. If you are a calf buyer then get pneumonia vaccination done by the breeder.
Case studies supplied by Kevin Beattie, Capontree Vets, Longtown; Rachel Tennant, Frame, Swift and Partners, Penrith; and James Frayne, Millcroft Veterinary Group, Cockermouth.