15 / 20
SUMMER 2016 ISSUE
LIVESTOCK MATTERS
14
BVD UPDATE
want to keep them
?
They may appear
perfectly healthy but their presence has a
knock-on detrimental effect on the rest of the
herd or group. For instance, where there is a
PI animal in a batch of calves, it is likely to
increase the incidence of scours and pneumonia.
‘One PI animal can wreck the whole herd.’
She advises: “With eradication the end goal,
it’s important that all dead calves are also
tested. If the calf is a PI, then their dam could
be one too. If she’s not tested and is a PI,
then she will not only be shedding the virus
and affecting her herdmates, but she will go
on to produce more PI calves in the following
years. So farmers need to either test the dead
calf, or test its dam. And if a calf does test
positive, then test its dam too.”
Biosecurity
BVD is highly contagious. It can be spread by
nose to nose contact. So biosecurity is
especially important where fields border those
containing cattle of unknown BVD status.
For farms in areas of high livestock density,
or where biosecurity measures are expensive
or difficult to install, then ongoing vaccination
may be recommended by the farm vet,
despite a herd being BVD free.
The buying-in of animals presents another risk
of the virus entering the herd.
Keith Cutler from Endell Veterinary Group
explains: ‘Ideally, a policy of only buying in
animals from herds herds accredited BVD-free
by a CHeCS registered cattle health scheme
should be adopted.
‘And regardless, all newly purchased animals
should be quarantined and tested on arrival
at the farm.
‘There are now a number of online databases
which allow the BVD status of a herd or
individual animal to be checked out prior to
purchase. This not only avoids the expense
of buying in a PI animal, but it also averts the
risk of other quarantined cattle being exposed
to the virus.’
The BVD CheckTag online database, set up
by XLVets in 2014, has the ear tag numbers
of over 77,000 BVD-free animals. These
results are being migrated into the new
national BVD-Free England database.
Your herd and BVD
BVD has already been eradicated from
Norway, Sweden, Finland and Denmark.
Other countries are in various stages of
instigating disease eradication plans.
But eradicating a disease from a country
takes time. The new BVDFree England
initiative has a goal of achieving eradication
by 2022. To achieve this will require
engagement from all English cattle farmers.
Keith adds: ‘Given sufficient engagement, it
is likely that voluntary schemes may be made
compulsory in time.
‘However, regardless of voluntary schemes or
compulsory regulations, there are financial and
herd health benefits in having a BVD-free herd.
‘Every farmer has access to the tools and
strategies to start their own BVD eradication
plan. By enlisting the help of their vet, a
programme can be devised which best suits
the farm and herd situation.’
The PI animal
Eradicating BVD requires the removal of all
Persistently Infected (PI) animals. These
animals will ultimately die prematurely from
the disease, however, meantime they will
shed the BVD virus and affect the health of
their herdmates. In-calf cows and heifers
exposed to the BVD virus may suffer abortions
or give birth to a PI calf. The BVD virus is also
detrimental to an animal’s immune defence
system, so animals exposed to the virus have
an increased susceptibility to other infections,
e.g. mastitis, pneumonia.
Keith Cutler, Endell Veterinary Group