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BVD CONTROL
SUMMER 2012 ISSUE
LIVESTOCK MATTERS
4
MICHAEL HEAD
All the 19 farms that originally enrolled on the scheme
are now BVD-free. Overall, its eradication has resulted
in fewer abortions - 1 per 50 pregnant cows fewer -
and there's also less calf disease on these farms.
Biosecurity measures
‘A BVD vaccination programme is just
one element of Nigel's best practice
approach to herd health,’ explains
Michael. ‘A few years ago, several cows
aborted due to leptospirosis, and there
had also been some Salmonella cases
in the past. So now cattle are vaccinated
against all three diseases.’
Nigel explains: ‘Biosecurity is difficult to
guarantee. Farm boundaries are never
100% secure so there's always the risk
that cattle might get out and mingle with
non-vaccinated animals.
‘I'd encourage any farmer who has
achieved a BVD-free herd to talk to their
neighbours and encourage them to
investigate what their herd status is for
BVD. Then measures can be taken to
protect against it.
‘We have definitely seen an improvement
in calf health over the past years, with less
pneumonia and scours. It's not possible to
attribute it to any one specific change in
management, but no doubt it's beneficial
that there is no BVD virus on the farm.’
BVD vaccinations are carried out in
combination with other jobs to make
efficient use of time. Cows are all
vaccinated for leptospirosis, salmonella
and BVD at the same time. ‘We time the
heifers' double dose so that the first one
is given at the same time as they are
drenched, and then typically they
get the second one when they are
freeze-branded,’ adds Nigel.
To ensure the disease has not been
introduced to the herd, each year,
blood samples are taken from around
20 yearling cattle to check for antibody
levels. In addition, monthly bulk tank
samples are taken - over time there has
been a gradual decline in the levels of
antibodies found indicating that the herd
has not experienced any recent exposure
to the BVD virus.
Michael adds: ‘All the 19 farms that
originally enrolled on the scheme are
now BVD-free. Overall, its eradication
has resulted in fewer abortions - 1 per
50 pregnant cows fewer - and there's
also less calf disease on these farms.’
Vaccinations give protection
Nigel continues to vaccinate his herds against
BVD, and together with Michael has established
biosecurity protocols to ensure that the herd
remains BVD-free.
Michael explains: ‘When Nigel buys in new
bulls or in-calf heifers, these are also blood
tested before being introduced to the rest of
the herd.
‘Few farms can claim to have a truly closed
herd, because most people will at some point
buy in a new bull. So biosecurity protocols
need to be drawn up and all bought-in stock
need to be quarantined and tested before
joining the rest of the herd.
‘For bulls, ideally blood tests should be carried
out before leaving the place of sale. On arrival
at the farm they should be quarantined for
at least two weeks. During this time, it is
recommended that they are drenched for fluke,
and have a sheath wash to remove any
possible campylobacter infection. An injection
of antibiotic such as di-hydrostreptomycin is also
advisable as this will reduce the risk of bringing
in leptospirosis by removing any residual
spirochaetes from the blood and kidneys.
Nigel Doman’s cows
Bulk milk sample
Nigel Doman’s calves