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HERD HEALTH STATUS
WINTER 2012 ISSUE
LIVESTOCK MATTERS
12
not over-worked, and depending on their
genetics, they may only be run with five cows
or as a maximum, 18. When Hollie PD-ed the
cows in May and October, all were in-calf.
There are rarely any calving difficulties, Chris
adds: ‘We don't often have to have help with
calving, but we always call the vet out if we
think we might have a problem, rather than
waiting until we do have a problem. These
cows are valuable, and so I don't worry
about the vet cost.’
It has been a closed herd for the past five
years, except for the buying in of new bulls.
These are always purchased from herds which
are certified as being disease-free for the key
infectious cattle diseases.
Gaining disease-free
accreditation
Hollie explains: ‘The Shentons already
manage the health of their herd very well. The
whole herd is vaccinated against BVD, and
calves are vaccinated against pneumonia.’
Hollie has registered the herd onto the SAC
Premium Cattle Health Scheme which certifies
the health status of herds for four key infectious
cattle diseases: - BVD, Johne's disease, IBR
and leptospirosis.
At Bridge Farm, the focus will initially be
targeted on Johne's disease and BVD.
Although the herd had been vaccinated
against BVD for the past seven years, the
Scheme required further testing. Hollie
explains: ‘We blood-tested calves looking
for the presence of BVD antibodies which
would have indicated the presence of
persistently infected - PI - animals in the
herd. These would then have had to be
identified and culled. Fortunately the herd
passed the first test with no evidence of
antibodies. The second test will be
undertaken next year and, provided that
is also clear, the herd will be classified
as a BVD-vaccinated-monitored herd.
‘The Shenton's cattle are kept in a number
of fields away from the main holding.
Although they have not found evidence
of BVD in the herd, this makes it harder to
monitor biosecurity across the boundaries.
Nevertheless, they take a 'belt and braces'
attitude, and the whole herd is vaccinated
against BVD to be on the safe side.
‘Johne's disease is a wasting disease that
takes several years to develop in an animal.
So with most bulls being sold at 1-2 years of
age, buyers often want assurance that they
are not introducing an animal into the herd
that could later develop the disease.
‘There haven't been any problems with Johne's
disease at Bridge Farm in the past. They have
recently passed the first of three tests showing
the herd is free from the disease.’
Hollie will annually blood-test all animals
over two years of age. Once the third round
of testing is clear, then the herd can be
registered as Johne's disease-free.
After that, the plan is to then address IBR and
leptospirosis. There is no history or evidence
of either disease in the herd to-date.
Bridge Farm is in a TB area. Chris is often
frustrated that this puts cattle sales at a
disadvantage, despite the fact that his stock
have always tested negative and are tested
more frequently for the disease, than those
in non-TB areas.
Trace element
deficiencies?
Taking a holistic approach to health,
Hollie has also suggested that the herd's
nutritional status should be investigated
and monitored on an ongoing basis.
She explains: ‘The soil in this area tends
to be deficient in the trace minerals -
copper, selenium and iodine. So it's
worth monitoring blood mineral levels
to check the cattle are receiving
adequate levels through their forages
and feed, and deficiencies are not
limiting performance.’
Blood-testing of calves earlier in the
year had revealed slight deficiencies in
selenium. This has been followed by
blood sampling of several in-calf cows.
Levels of selenium and copper have
proven normal. ‘If they had been low,
I'd have recommended that adult cattle
be given a mineral bolus with a sustained
release,’ adds Hollie. ‘It's an area I
intend to keep an eye on.’
It's been a memorable year. Triple wins in
the breed society's annual competitions,
new proactive veterinary care, and the
start of the journey towards an accredited
high health status for the herd.
Chris Shenton
Mark Shenton, Hollie Dale and Chris Shenton