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LIVESTOCK MATTERS
BVD UPDATE
Eradicating BVD from your herd:
strategies and tools
BVD has been recognised as one of the biggest disease issues affecting the UK national
herd. Over the past few years, a number of voluntary and compulsory schemes have been
put in place in different regions, as part of co-ordinated industry and government efforts to
eradicate the disease. Most recently, BVDFree England was launched (see News section).
Here, three XLVets vets outline some of the strategies and tools available for farmers to
initiate their own BVD eradication programme for their herd.
Routes to eradication
Eradication requires the removal of all PI animals.
Andrew Millar of Ardene House Vet Practice,
Aberdeen explains: ‘Vaccinating a herd
against BVD will limit the performance-
depressing effects of the virus that is shed
by PI animals, but it will not eradicate the
disease.
‘The main aim of vaccination of the breeding
cattle is to reduce the risk of more PI animals
being created when a foetus becomes
infected in the early stages of gestation.
‘There are various routes to establishing if a
herd contains any PI animals. The first is to go
on a PI hunt: test all calves which are born for
BVD virus, and any cows or heifers which
have not yet produced a calf for testing. All
breeding bulls used on the farm also require
a BVD virus test.
‘A PI heifer or cow will always produce a
BVD PI calf. And it can be assumed that the
dams of any calf born which tests BVD virus
negative, are not PI.
‘This is a quick route to BVD eradication but
the upfront cost can be a deterrent to some
farmers.
‘In Scotland, prior to the Scottish Government’s
BVD eradication scheme, some herds only
tested their bulls and any heifers prior to them
joining the breeding herd. This ensured no PIs
were added to the herd, so eventually any PI
cows would be removed from the breeding
herd when culled for other reasons. These
herds usually used BVD vaccination as an
additional biosecurity measure. This alternative
method had a lower annual cost, but is a
slower method for BVD eradication.
‘Once a herd has removed all BVD PIs then
it’s important that some method of monitoring
is instigated, to make sure the herd remains
BVD virus free. This can be done at a
reasonable cost by using a check test on
animals aged between 9 and 18 months of
age. Five animals from each management
group should be tested for BVD antibody
and this will show if they have met any
animals shedding BVD virus. It is best to wait
until animals are over 9 months old so that
any maternal-derived antibody will have
disappeared. Care must also be taken if
vaccines for BVD are used prior to the BVD
check test.
‘Once a farm has become BVD-free, then
with good biosecurity, the actual cost of
annual testing to monitor the herd status,
is minimal.’
In Scotland a national eradication programme
was begun by the Scottish Government (SG)
in 2010. It includes the annual testing of
herds for BVD, and then classifying them as
‘negative’ for BVD, or ‘not negative’. Stage
four of the plan came into force in June
2015, and it is now illegal to knowingly sell
or move BVD-infected animals.
Testing calves
The advent of Tag and Test ear tags has
enabled the early detection of any PI animals
born on the farm.
This tool plays a key role in Northern Ireland’s
eradication programme: it is now compulsory
for all calves born to be tested for BVD. Test
results are uploaded onto an online database
and no animal can be sold without proof that
it is BVD-free.
Treenie Bowser from Parklands Veterinary
Group explains: “This new regulation came
into force in March this year. It came after a
three-year voluntary scheme in which farmers
were encouraged to adopt this early start
approach.
“Although there’s no rule to cull animals
identified as being PI, why would anyone
Treenie Bowser, Parklands Veterinary Group
Andrew Millar, Ardene Veterinary Practice