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Regulars
I
Zoetis pages
Administer wormers
effectively
• Dose at an appropriate time.
• Weigh the animals – do not guess
the weight.
• Use the correct dosing technique
when administering the product.
• Ensure that products are stored
correctly and are within the expiry
date.
• Do not mix wormers together –
unless specifically specified on the
bottle.
• Use wormers only when necessary
and use grazing management to
reduce the challenge.
Target treatment
• Target the correct worms by taking
egg counts in dung.
• Test to find out if wormers are
effective. One way is to drench the
sheep and take an egg count 7 -14
days later.
• Ensure that some susceptible
worms survive treatment.
• Do not move animals directly onto
new pastures.
Dr Bartram warned that global
warming would affect parasitism. Most
of the worm population live
free on pastures and thus
escape anthelmintic
treatment. He also
advises farmers to
use techniques
such as the
Famacha® test.
“Avoid grazing
goats and sheep
together. Goats
do not become
fully immune and
worms develop
resistance in
goats faster than in
sheep.”
Other methods of
worm control include
breeding for resistance.
“Also make sure that you don’t
use long acting wormers continuously
on the farm. Use these in conjunction
with other wormers.”
According to Dr Bartram the current
thinking is that annual rotation is
not necessary the best thing to do.
“Use different effective anthelmintic
classes within the same year to slow
resistance development.
v
TIMELINE FROM ANTHELMINTIC INTRODUCTION TO FIRST RESISTANCE
Symbol
Anthelmintic group
Compound
Launch
First report of AR
1-BZ
benzimidazoles
thiabendazole
1961
1964
2-LV
imidothiazole
levamisole
1970
1979
3-ML
avermectins
ivermectin
1981
1988
milbemycin
moxidectin
1991
1995
4-AD
amino-acetonitrile derivative
monepantel
2009
20131
5-SI
spiroindole
derquantel
2011
none
Mei/May 2015
35
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