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Problems with worm control |
- The worming
drugs currently available for
use in horses are extremely
effective. However, horse owners
should realise that individual
drugs only treat certain worms
and that some drugs only treat
some of the life-cycle stages of
certain worms. A further
complicating factor is that some
worms have developed resistance
to certain worming drugs. The
more frequently worms are
exposed to the drug, the greater
the chance of resistance
developing. The bottom line: It
is not as simple as giving a
dose of wormer and all the worms
are killed!
- Not all
horses are equal! Some horses
are predisposed to worm
infection and are likely to
become repeatedly infected with
heavy worm burdens. Many horses
however, are relatively
resistant to developing heavy
burdens. With such a variation
in individual susceptibility it
makes no sense to treat all
horses the same.
- Most horse
owners have struggled with the
question of which worming regime
is best for their horse. Because
every horse is different, and
because the conditions under
which every horse is kept are
different, there is no single
worming regimen that suits every
horse. Your vet is the person
best placed to advise on your
particular situation.
- Environmental
issues are never far from the
news headlines. Did you realise
that some worming drugs have a
marked impact on the
environment? Residual drug
activity is present in droppings
when they fall onto pasture.
This will lead to the death of
insects and earthworms that
usually break up the pile of
droppings. This does not mean
that worming drugs should not be
used. It does mean that they
should be used sparingly and
only when necessary.
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Pasture hygiene
Scientific studies have
demonstrated the effectiveness of
regular removal of droppings from
horse pasture. If this is done twice
a week, there is minimal
transmission of worms between
horses. Other management techniques
that can be used are rotation of
pasture and grazing sheep or cattle
on the same pasture. These species
will eat the eggs of the horse worms
without becoming infected, thereby
acting as "biological vacuum
cleaners!
Targeted
dosing with worming drugs
By using diagnostic tests,
heavily infected horses can be
identified and treated. Non-infected
horses do not need treating thus
saving money on expensive drugs,
reducing the tendency for resistance
to develop and leading to less
impact on the environment. Periodic
diagnostic testing is essential for
this method of control. Not only
does this allow targeting of worming
drugs it allows horse owners to
check that their worm control
programme really is working.
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Interval treatment with
worming drugs
This technique involves
the repeated use of worming drugs at
specified intervals. At each treatment, more
than 90% of the worms are killed (depending
upon the drug used) and the period between
treatments is defined by the speed at which
the horse develops an adult population of
worms in its intestine once again. This
regime inevitably involves the treatment of
many horses that have only low levels of
infection. However, under certain
circumstances, it is the only safe approach
to worm control.
Diagnostic tests
Until recently, horse
owners have been happy to assume that all
their horses are infected with worms and to
use interval dosing with worming drugs.
There is an increasing awareness that
diagnostic tests, interpreted by veterinary
surgeons, can help identify heavily infected
horses and help to target treatment.
- Do you want to spend
less on worming drugs?
- Are you interested in
a "greener" approach to worm control?
- Are you worried about
resistance to worming drugs?
If you answer "yes" to any
of these questions then a targeted worming
regime may be for you!
A simple worm egg count on
a sample of droppings gives an indication of
the number of adult redworms a horse is
carrying. It will also reveal large
roundworm infection. Tapeworm infection has
traditionally been more difficult to
diagnose. Research work at Liverpool
University Veterinary School has lead to the
recent development of a blood test for
tapeworm infection. Both of these tests are
now available to veterinary surgeons through
"Diagnosteq," a specialist parasite
diagnostic service run by the University of
Liverpool.
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Benefits
of testing for worms |
By targeting treatment with
worming drugs at only those horses with
significant levels of infection, horses and
their owners can benefit in a number of
ways:
- Reduced expenditure
on worming drugs.
- Reduced pressure on
the worms to develop drug resistance.
- Reduced environmental
impact due to unnecessary use of
wormers.
These benefits arise at
the same time as owners knowing that
worms are controlled in their horses. They
know this because they have test results to
prove it!
This approach to worm
control is not just scientific theory. We
know that it works. An increasing number of
horse owners and vets are using diagnostic
tests to target worming drugs. Most owners
who try this method find it to be cost
effective and are pleased with the "peace of
mind" that it brings them. Diagnostic tests
have also been used to help reduce the
incidence of colic in yards with worm
problems.
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Article
kindly supplied by:- Diagnosteq, "Solutions to worm control",
Equine Division, Leahurst, Neston, Wirral
CH64 7TE
Tel/Fax: 0151 794 6184 email:
diagnost@liverpool.ac.uk |
