BVD SUPPLEMENT
LIVESTOCK MATTERS - BVD SUPPLEMENT
For Cheshire beef suckler producer
Nigel Potts, poor growth rates in
some calves – highlighted by
dramatic variation in performance
across groups – had become an
unacceptable drain on profitability
for his 160-cow enterprise.
There were also periodic abortions at
Mount Farm, near Macclesfield, as well
as other fertility issues such as heifers
apparently not holding to service.
The situation was frustrating, because
Nigel had always worked hard at
maintaining good health status in his
herd, and it was a surprise when the
farm’s vet Hollie Dale of Wright &
Morten near Macclesfield suggested
Bovine Viral Diarrhoea (BVD) might be
at the root of his problems.
“We maintain a lot of the good herd
health habits that we applied as dairy
farmers before going out of milk 10
years ago,” says Nigel, “and this
includes vaccinating against BVD
and leptospirosis.
“We also run what is essentially a
closed herd, with bulls being the only
stock coming in from outside, so I think
our biosecurity is pretty good. I was not
initially convinced that we could have
had a major infectious disease problem,
but it was clear something was not
right and blood testing was available
through our vet that enabled us to
check the herd’s status.”
Blood samples were initially taken
from unvaccinated heifers by Hollie,
and the results from this were the
first step in establishing the root
cause of the problems.
“We started with a group of heifers
that were not holding to natural
service, checking five of the animals for
evidence of exposure to the BVD virus,”
recalls Hollie. “Several heifers were
positive for BVD, so we then tested
another group of nine month old
heifers and found some of these also to
be positive for BVD. It was clear the
disease was circulating in the herd.
“BVD is most commonly spread within
a herd through close contact with what
is termed a PI – or a persistently
infected animal. PI’s are created when a
naive (unprotected) cow or heifer
becomes infected with the BVD virus in
the first 120 days of her pregnancy;
when this happens, the calf she is
carrying can often be a PI. This animal
may appear normal and will have the
potential to survive in the herd as a
perpetual source of BVD infection,
shedding virus constantly throughout
its life.
“When we investigated the vaccination
procedure on the farm, it became clear
that heifers were at times not being
vaccinated before bulling, and hence
they were at risk of creating PIs if they
became infected with the virus in early
pregnancy.”
This situation at Mount Farm provides a
classic example of how infection can
circulate and present problems, despite
vaccination taking place. It is also an
illustration of how the first step must
be to remove PIs before a vaccination
programme can be effective.
“Once we’d established that BVD was
ELIMINATINGVIRUS BOOSTS BEEF
HERD FERTILITYAND GROWTH RATES
Nigel Potts has worked hard with his vet Hollie Dale from Wright
and Morten to eradicate BVD from his beef suckler herd.
Wright & Morten
