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Using flukicides
correctly
It is important that both drug and non-drug
control measures are used together, rather than
relying on medicines alone.
To treat liver fluke, you need to strategically
treat with a flukicide product tailored to the
stage of the fluke lifecycle. The stage of the
fluke lifecycle is determined by the time of
year and local farm factors such as climate,
grazing management, stocking density, ground
conditions etc. As a result the dosing regime
must be tailored to the individual farm. There is
no such thing as a 'routine' or 'blanket' control
programme. A Fluke control programme
should be incorporated into the individual
farm's health plan.
As with all medicines it is important to store
and use them appropriately. For example
many data sheets read 'store in a dark place
below 25
o
C'. Whilst data sheets may not
represent the most stimulating read and can
induce a state of stupor, their content is vitally
important as failure to abide by these
guidelines may result in reduced drug efficacy.
The car or truck dashboard or passenger seat
is not a suitable drug cabinet!
Ensure all drenching equipment is clean and
correctly calibrated before use, and DO NOT
mix products in the same drench. Accurate
dosing according to weight is very important
as under dosing is a strong driver for
resistance, whilst overdosing risks toxicity. As
a rule of thumb, treat according to the heaviest
in the group. If wide weight variation exists
split the group into two, allowing for smaller
and more even groups and then dose to the
heaviest in each group.
In summary
The whole-farm approach to prevention
and appropriate treatment will become
increasingly important. Our reliance on
flukicides will need to be reduced, either
due to legislation limiting the flukicides
available, or the ever present threat of
resistance. Planning now for the future is
important as many of the prevention
strategies require considerable investment
of time and money, and some farmers
may find that the requirements of their
agri-environmental scheme do not match
their fluke control requirements.
However, there is some good news.
Trials for a vaccine are currently
underway and in the future, we may
have a vaccine available for
fluke control.
L I VER F LUKE
11
LIVESTOCK MATTERS
WORKING
TOGETHER
FOR A HEALTHIER FUTURE...
Available flukicides
Only a limited number of products are
available, and a key point is that not all will
kill all the different stages of the fluke life cycle,
and there is even variation in susceptibility
within the ages of the individual stages of the
life cycle e.g. triclabendazole has activity
against the mature and immature fluke down to
two weeks in cattle, whereas Nitroxnil injection
only has activity down to 6 weeks, (so fluke
less than six weeks old will not be killed by
Nitroxinil). Albendazole only kills adult fluke.
Also, there is variation between the different
methods of application e.g. oral preparations
kill younger stages than pour-on preparations.
These points are important, as most of the liver
damage is caused by the migrating immature
fluke. Also, the inability to kill the earlier stages
means that repeat treatments may be needed
approximately 8-10 weeks later - those fluke
in the earlier stages will then be within the
age of the'killing zone' and any adult flukes
developed since the last treatment can be
killed before they start producing large numbers
of eggs.
Treatment for an acute outbreak of disease
should include the use of a product containing
triclabendazole as this kills all stages of the
parasite. However, due to increasing concerns
over resistance, it may be prudent to use
another product e.g. closantel, which will
remove any late immature or adult flukes
present which have escaped the effects of
triclabendazole. No other flukicide is
available that offers the wide spectrum of
activity of triclabendazole.
No flukicide
has any kind of persistent
action - so re-infection can occur
immediately after treatment.
For further information and advice on the
treatment and control of liver fluke contact
your XLVets practice.