Basic HTML Version
L I VER F LUKE
AUTUMN 2013 ISSUE
LIVESTOCK MATTERS
10
Testing
Faeces test for eggs (FEC’s):
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Eggs are only produced by adults, so
any test will be negative for the first
twelve weeks of infection
Slaughterhouse information
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Most abattoirs will report when livers are
condemned due to fluke damage
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Proves current infection
Before embarking on a liver fluke treatment
regime it is important to determine whether
a fluke problem actually exists on your
farm. Treating unnecessarily costs you
money and time, and promotes resistance.
Testing for liver fluke can be done in the
following ways:
Using these tests makes it possible to build
a strong picture of the overall parasite
burden on farm, not just fluke.
Farm plan
Once fluke is confirmed, the farm will need its own individual
plan drawn up, as conditions and risks will vary considerably.
Two principles need to be followed - reducing infection, and
appropriate monitoring and medicine use.
Reducing infection
Monitoring and
medicines use
The fluke that infects cattle and sheep
is capable of infecting any mammal - e.g.
rabbits, deer - making infection impossible
to eliminate. This means that grazing
areas with snail habitats will remain
permanently infected, even if left
un-stocked for several years. Whilst
strategic treatment using flukicides will
help control the problem, long term
there will need to be a move towards
preventing infection and reducing our
reliance on medicines, as is happening
with gut worms.
Therefore limiting new infections relies
on preventing access of the grazing
animals to snail habitats, or removing
snail habitats from the farm.
Possibilities include:
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Treatment frequency during the
grazing season will depend on
environmental conditions e.g. wet
summers provide greater habitats for
the intermediate host snail and
encourage proliferation of both the
snail and fluke. NADIS provide
regional forecast summaries which can
help to decide treatment protocols.
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Treat with the right product at the right
time of year e.g. use a product that
kills immature stages in October, and
one that kills mature stages in January.
Rotate flukicides on a yearly basis to
reduce resistance.
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Perform regular FECs - however, egg
shedding is intermittent, and none are
produced until adult fluke are present
12 weeks after infection.
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Investigate all case of ill thrift -
remember plenty of other causes exist
e.g. trace element deficiency, dental
disease, lameness, chronic conditions
such as Johne's and Scrapie etc.
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Investigate sudden deaths - clostridial
disease commonly causes sudden
deaths secondary to liver tissue
damage caused by an underlying
fluke problem.
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Quarantine bought in stock and use a
flukicide to avoid introducing fluke in
animals carrying the parasite. As levels
of resistance to the fluke medications
rise, it may become prudent to dose
using two different fluke medicines
at quarantine.
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Resistance,(especially to triclabendazole),
is increasing so any perceived treatment
failures should be thoroughly investigated.
Each option has limitations. For example,
some wet, rushy fields are only
appropriate for grazing stock; the ground
is too poor for good silage making or
too wet to take the machinery. In other
cases, the river, which is the source of
infection, is also the water source for
the livestock and spending all winter
defrosting water troughs is impractical.
However, farmers need to consider what
is possible on their farm.
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Not grazing known ‘fluke’ fields
- a
possibility if only some fields have a
known fluke problem, assuming there is
sufficient other grazing, and the 'fluke'
fields can be used for silaging etc.
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Strategic grazing
- it may be possible
to limit grazing of 'fluke' areas in the
autumn, limiting the number of new
flukes entering the animals.
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Fencing ‘fluke’ areas
- this will prevent
new fluke infections but some farms
may need to run an alternative water
source to certain fields.
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Long term drainage of fields
-
removal of the damp areas will remove
the snail habitat and therefore the
fluke risk.