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BVD CONTROL
SPRING 2012 ISSUE
LIVESTOCK MATTERS
4
BVD
Control
Bovine Viral Diarrhoea (BVD) is one of the most significant production diseases affecting UK cattle. This is
not only because of its direct impact on fertility but, through the suppression of immunity, it allows pneumonia
and other infectious disease to gain hold. Moreover, it is extremely widespread. Knowing the disease status
of your herd, bought-in stock, replacement heifers and even loaned bulls is essential if the disease is to be
successfully controlled.
According to MSD Animal Health's
DairyCheck and BeefCheck subsidised bulk
milk and blood testing schemes, 69% of dairy
herds and 60% of beef herds have been
exposed to BVD. These levels are worryingly
high considering that BVD is a disease spread
when levels of the virus are circulating in a
herd, shed by either transiently infected or
PI (Persistently Infected) animals.
The signs of BVD are hard to spot which can
mean they go unnoticed and are even seen
as 'normal' for that herd. Unchecked and
unseen, this disease can lead to significant
economic losses. BVD causes most damage
when it infects pregnant cows. Foetal death,
mummification of the foetus and abortions are
possibilities at any stage but if infection occurs
at between 40-120 days into the pregnancy,
a PI calf can be born. A PI will be born alive,
often seemingly healthy, but will excrete virus
into the environment at all times, acting as a
source of infection to other cattle before dying
months or years later. To prevent the birth of PIs,
vaccination of breeding cattle with a suitable
vaccine would be recommended to prevent
the birth of PI calves. Your XLVets practice will
be able to provide further advice on
vaccination regimes.
Results from a research study undertaken by
a student at the Royal Veterinary College
1
and presented at a veterinary conference
revealed some worrying lapses in BVD
vaccine use on-farm.
The study was carried out on 71 farms, split
between beef and dairy and found that:
l
21% of farmers vaccinated using the
incorrect dose of vaccine.
l
A similar number administered
vaccine via the incorrect route
of administration.
l
While all farmers gave a two-course
primary course, nearly 50% had the
wrong amount of time between dose
1 and dose 2.
l
Critically, vaccine should be given
four weeks before service to ensure
that the unborn calf is protected, yet
just 24% of respondents managed to
do this.
PART 1
OF A TWO PART SERIES