Livestock Matters - Autumn 2016

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AUTUMN 2016 ISSUE LIVESTOCK MATTERS 6
BUYING IN SHEEP
Enzootic abortion
’Enzootic abortion is still a common cause of
abortion, despite an effective vaccine being
available. Unfortunately there is no way of
knowing if a sheep is carrying the infection.
The bacteria that cause the disease can lie
dormant until lambing time and blood tests
are unreliable for diagnosing infection in
individuals. So any bought in ewes should
be considered a risk.’
Bryony advises: ’It is good practice to keep
bought in sheep separate from the main
flock until after lambing to reduce the risk of
disease spread at lambing time.’
Preventive actions: If routinely buying
replacements, consider vaccinating the flock
or source from accredited EAE-free flocks
which are listed on the Premium Sheep and
Goat Health Scheme database at
Sheep scab
’Scab is caused by a mite living on the skin
of the sheep. It is incredibly contagious and
causes intense itching leading to production
losses. One of the problems with buying
sheep is that they can be carrying scab
without showing any signs; in the early stages
it is undetectable. There is also the possibility
of mites being picked up from the market or
transport lorry.’
Actions required: The only way of knowing
for sure that your sheep do not have scab, is
to treat them on arrival with an appropriate
macrocyclic lactone injection, or dip them.
SCOPS recommend a 1% moxidectin
injection, but this must not be used in sheep
that have ever had or are likely to have the
vaccine against footrot. There are other
macrocyclic lactone injections available,
but they differ in how long they last and how
many injections are required. It is best to
consult your vet as to which is the most
appropriate treatment.
Worms
'Resistant worms are one of the major issues
currently facing the sheep industry.
Resistance to one or all of the three older
generation wormers is commonplace,
resulting in delayed finishing times, and
wasted time and money. Even fit sheep can
be carrying resistant worms, and these will
contaminate previously ‘clean’ land.
'Another threat to flock health is the
blood-sucking worm Haemonchus contortus.
It is not present on every farm, but its effects
can be devastating. It affects lambs and
adult sheep and is seen in late summer and
autumn. Heavy burdens will cause anaemia,
resulting in weight loss, reduced production
and death.’
Actions required: Give all bought-in sheep a
complete clear out with a double wormer
treatment. Use one of the new generation
wormers (orange 4-AD or purple 5-SI)
teamed with a macrocyclic lactone injection
(i.e. the injection used for sheep scab). This
is a belt and braces approach to ensure
only a very small possibility of any worms
surviving treatment.
It is important to keep sheep yarded for 48
hours after treatment to allow all eggs to
pass out in the dung. This dung should not
be spread onto any grazing pasture. Then
turn out on to dirty pasture (land that has
been grazed by sheep within the past 12
months) just in case any worms have
survived the 2 treatments. The resistant
worms would therefore be diluted amongst
existing worms and they would have less of
an effect than if on clean pasture.
Check out the SCOPS website
for further information
on tackling wormer resistance, and discuss
with your vet as to the best protocol.
Lameness
’Quarantine treatment is one of the elements
of the 5 Point Plan for lameness control and
is a ’must do’ for reducing levels of lameness
in your flock.
‘However, all too frequently contagious ovine
digital dermatitis – CODD – and highly
virulent strains of footrot are introduced into a
flock on the feet of bought-in sheep. Some
lesions can be very subtle and so some sheep
may carry bacteria without showing much sign
of lameness.’
Actions required: It is important to: 1) isolate
sheep for at least 3 weeks so that lameness
can be identified, and 2) to inspect all their
feet. If footrot and/or CODD are found, treat
with an appropriate antibiotic. In addition, put
the group through a footbath or spray all feet
with an antibiotic spray. Remember to continue
to isolate until the lameness is fully resolved.
Liver fluke
’Liver fluke is a common parasite in many
parts of the country. It causes weight loss
and poor performance, and in many
cases death. It can be difficult to treat
and manage, and there have been an
increasing number of reports of flukicide
resistance. So if a farm is fluke free, don’t
let it in!’ says Bryony.
Actions required: Treat for fluke during the
quarantine period and if possible, turn
stock out onto ground with a low fluke
risk. The choice of product might vary
with the time of year and the risk of
bringing in resistance; consult your vet for
farm-specific advice.
Wasting diseases
‘Maedi-Visna (MV) and Caseous
Lymphadenitis (CLA) are both wasting
diseases of which there are accredited-free
health schemes. Sourcing from these flocks
will reduce the chances of bringing in these
diseases. Unfortunately, no such schemes
currently exist for Johne’s Disease or Ovine
Pulmonary Adenocarcinoma, and testing
for these is problematic.’
Preventive action: Private sale and
knowledge of the flock of origin will give
the best chance of avoiding buying in
these diseases. For information on flocks
which are accredited free of Maedi Visna
and CLA, visit the PSGHS database at
Stay biosecure
'Biosecurity protocols are part of every flock
health plan and farm assurance schemes,
but ignoring them puts the health and
productivity of the rest of the flock at risk.
So if in doubt as to whether your quarantine
protocol is adequate, then discuss it with
your vet and revamp the quarantine
procedures for your farm,' recommends
Bryony.
’Not only is it far less costly to prevent
disease than to treat it, but some sheep
diseases are very difficult to eradicate
once they have arrived on-farm.’
The feet of all bought-in sheep should be
inspected for signs of CODD or footrot
Liver fluke infection in sheep is on the increase
across the UK