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WORKING
TOGETHER
FOR A HEALTHIER FUTURE...
13
LIVESTOCK MATTERS
Prevention and control of common
diseases of (dairy) sheep and goats
SHEEP AND GOAT
CONFERENCE
Friars Moor Team: Back row, left to right Lucy
Hepworth, Sarah Eckett, Eleanor Price and
Izzy Place. In the front: Yoav Alony-Gilboa and
Anthony Wilkinson.
Earlier this year, Dorset vet practice
Friars Moor Livestock Health held an
inaugural conference for those
involved in milking sheep and goats.
The two-day event was a sell-out
success with just over 100 delegates
attending.
Amongst the speakers were well-known
veterinary consultant David Harwood who
outlined the key clostridial diseases affecting
sheep and goats, and Mick Millar from
the University of Bristol who introduced
the concept of ‘iceberg’ diseases to the
audience.
‘Clostridial diseases are caused by anaerobic
bacilli of the family clostridia,’ explained
David Harwood. ‘They are widely distributed
in the environment, and are the classic cause
of sudden death in sheep, and also an
important cause of diarrhoea and death in
dairy goats.
Clostridial diseases
‘A lot of healthy animals have low levels of
clostridia in their gut and it is only when an
animal’s natural immunity is compromised that
clostridial diseases become a problem.
‘These disease outbreaks are unpredictable,
but trigger factors include a sudden change in
diet particularly with associated acidosis, a
change such as turnout to lush grazing, or
housing, and any stresses, e.g. bullying, or the
presence of other disease.
‘This means farm biosecurity is of little value in
preventing clostridial diseases, and control is
best achieved with vaccination.’
There are many types of Clostridia in the
environment, but at least ten have been
reported as causing disease and death in
ruminants. David highlighted some of the
most common.
‘Tetanus can occur in both sheep and goats
following surgical intervention such as
castration, or wound infection; the classical
signs are early stiffness when walking followed
by tetanic spasms and bloat. Treatment is
disappointing and so the focus should be
on prevention.
‘In lambs, pulpy kidney is a very common
clostridial disease. Since death occurs in less
than 24 hours, farmers are more likely to find
a dead lamb than actually witness clinical
signs. If still alive however, lambs typically
display star-gazing behaviour.’
David explained that black disease and black
leg disease are the outcome of a
gas-gangrenous type of clostridial infection.
Black disease is linked with fluke infection;
as the fluke migrate through liver tissue they
activate dormant spores of clostridia and
outbreaks occur. So fluke control is a factor
in its prevention, as well as vaccination.
Another clostridial disease – Malignant
Oedema – can arise when damage is
incurred in lambing or kidding. It creates a
severe swelling (oedema) in the anal and
perineal area. David advised farmers to
discuss with their vets a protocol for using
an antibiotic for lambing or kidding injuries.
In goats, the main Clostridial threats are tetanus
and Enterotoaxaemia. Clinical signs of
Enterotoxaemia can be rapid death, but at
sub-acute levels, there will be profuse diarrhoea.
Vaccination
There are several different vaccines with a
marketing authorisation for sheep, which
can give protection for up to 10 different
clostridial diseases.
However, there are no licensed vaccines for
use in goats, but as they only need protection
against enterotoxaemia and tetanus, David
recommends a 4-in-1 vaccine. But as goats
develop only a poor immunity, a booster
vaccination should be given every six months,
or more frequently if the vet advises. He added:
‘There’s no damage caused by over-vaccinating.’
He recommends that farmers take advantage
of vaccines which protect against Pasteurella
as well as clostridial diseases.
He said timing of vaccination is important,
and also that the strategic use of boosters in
the run up to lambing/kidding (6 to 2 weeks
before) can maximise antibodies in the
colostrum. All stock – including rams/bucks –
should be vaccinated and the manufacturer’s
recommendations need to be followed.
Star-gazing lamb
David Harwood