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here are still a small number of
breakdowns occurring which will take
a sustained effort to eradicate, he says.
We need to remain vigilant and not let our
guard down. BVD is such a troublesome
disease that a single PI animal will quickly
undo all the hard work gone before, just by
coming into contact with other animals. He
admits that the scale of the disease caught
everyone by surprise during the late nineties.
We knew that BVD was causing problems
in some herds, but when repeated tests kept
coming back positive, action needed to be
taken because of the concentration of cattle
in Orkney.
Northvet fully supported OLA's farmer-led
formation by providing technical advice
and updates. A huge effort was put into
organising a large number of parish level
meetings to explain about the disease
and how animal health planning and
vaccination could work.
The meetings were very well attended.
Some farmers really 'opened up' about
disease levels on their own farms. Despite
initial scepticism by a few in the supply
chain, particularly as the vaccines were
very new, the majority became convinced
by the island-wide approach. To tackle BVD
successfully, it's either all or nothing,
adds Mr McCulloch.
He says the idea to operate an 'excellent'
traffic light status system developed by
Andrew Curwen, a then industry vet
working for a vaccine supplier, also helped
simplify monitoring and action.
During the formative years of the scheme,
some farms chose to keep PI animals on the
holding, but isolated from the rest of the
herd because no compensation was
available for slaughtered animals.
We thought we could contain and control
PI's, but it's virtually impossible. We've
learned a lot since then and now we
advocate removal and slaughter of all PI's.
The loss of an animal is not insignificant but
it pays to remove them in the long term.
Mr McCulloch reports that PI's are thankfully
now at very low numbers and with a little
bit of investigation a vet and farmer can
pinpoint how each individual case occurred.
The added benefits of controlling BVD
have been many, not least the greater
number of healthy calves born and also
the large reduction in sick calves with
scour and pneumonia.
Many still remember the many hours
spent nursing sickly calves. Stopping this
has reduced stress levels both for animals
and their keepers. Many have regained a
pride and satisfaction in their jobs.
Furthermore, Orkney's reputation for
producing healthy, quality stock has helped
maintain and improve the high demand
from mainland buyers.
Northvet, through practical farm health
plans, is also helping farmers tackle Johne's
disease using blood testing and faecal
examination every 12 months with positive
cases slaughtered.
The main signs in cattle are progressive
weight loss and chronic diarrhoea and
losses can exceed 5% in a herd. Just like
BVD it is critical that all measures are taken
to prevent introduction of infection because
eradication of disease once prevalent in the
herd proves very costly and may take many
years to eradicate, advises Mr McCulloch.
Orkney's beef and dairy farmers can be justifiably
proud of the unique island-wide collaborative
approach, but we aren't celebrating just
yet, explains XLVets' Iain McCulloch of
Kirkwall-based practice Northvet.
I A I N MCCU L LOCH
O R K N E Y B V D
l
70 islands - 17 inhabited
l
Around 500 active farm holdings
l
Covering 95,000 hectares
(237,000 acres)
l
Mainly low lying, fertile soils
l
Temperate climate, warmed by
Gulf Stream
l
2,000 employed in agriculture both
full and part-time
l
Highest density of beef cattle
in Europe
l
100,000 cattle, mostly suckler
cows and followers
l
Around 2,500 dairy cows
l
About 500 beef units
l
Typical herd size is around 85 cows
l
A viral disease of cattle caused by
a Pestivirus
l
Considered widespread in UK
cattle herds
l
Infection with BVD may cause or
contribute to:
l
Reproductive failure (infertility,
abortion, foetal mummification)
l
Respiratory disease
l
Gastrointestinal disease
l
Congenital defects
l
Immunosuppression
l
Subclinical infection
l
Persistently infected (PI) calves likely
to die of mucosal disease before two
years of age.
THE DAMAGING EFFECTS OF
BOVINE VIRAL DIARRHOEA (BVD)
ORKNEY
FACTS
£50
PER COW
- the increase in profitability in
BVD free herds
TRAFFIC LIGHT
WARNING SYSTEM
378 PI cattle
during 2001-2002
14 PI cattle
during 2005-2006
Other fundamental rules of the scheme
l
Bought-in stock must be isolated for
3 weeks and tested
l
Clean and disinfect shared
machinery, equipment, livestock
trailers and handling facilities
after use
l
Restrict visitors
l
Follow good general bio-security
measures at all times
RULES
OF THE SCHEME
45%
the amount of abortions and
neonatal deaths caused by BVD at the
start of the eradication programme
Orkney's cattle BVD status is recorded as:
l
White
- Antibody Negative and
Virus/Antigen Negative. Animals
that have not been exposed to
the disease.
l
Green
- Antibody Positive. Animals
that have been exposed to BVD.
l
Red
- Virus/Antigen Positive. Animals
infected in the womb. Continue to
shed virus after birth. Commonly
referred to as Persistently Infected (PI's).
85%
the number of farmers that
are OLA members
SPRING 2010 ISSUE
LIVESTOCK MATTERS
12