36 / 52
Regulars
I
Zoetis pages
34
Mei/May 2015
vet
nuus
•
news
T
his is according to Dr
David Bartram, Director,
Marketing & Integrated
Solutions - Ruminants,
Zoetis, recipient
of the British Veterinary
Association’s Chiron
Award 2013 for
outstanding
contributions to
the veterinary
profession, and a
veterinary scientist
and author. Resistance
is the heritable (and
therefore genetic) ability
of the worm to survive a
dose of anthelmintic which would
normally be effective. It could also
be described as ‘drug tolerance’
in worms. A worm is said to be
resistant if it survives exposure to the
standard recommended dose of the
anthelmintic and can then pass this
ability on to its offspring.
Managing resistance is important
since production losses can occur
even when the parasitism caused
by anthelmintic resistance is
subclinical. By using an
affective anthelmintic
growth performance
is increased and the
benefits can greatly
exceed the costs of the
anthelmintic.
Dr Bartram cautions that
resistance is inevitably a
consequence of good worm
control and could emerge within
two to four years with some products.
“Once resistance has emerged in a
flock, the worms can no longer be
controlled effectively using a particular
anthelmintic class. However, in most
flocks or herds, worms can still be
adequately controlled when resistance
is present. Resistant worms do not
cause more serious disease than
susceptible worms.”
In order to use anthelmintics
sustainably the following guidelines
are important:
Dosing strategy
• Plan a dosing strategy
• Don’t use blueprints or a set recipe.
Tailor the planning for the individual
farm.
• Use an effective, multiple
active wormer, such as Startect
(Derquantel and Abermectin).
Quarantine
It is important to quarantine and treat
all introduced sheep on arrival. Hold
these sheep off new pastures for at
least 24 to 48 hours before turning
them out into contaminated pastures.
No matter how expensive the animal...
it could still carry resistant worms.
Worm Resistance:
A threat to industry
Dr BB van Houten, Zoetis™
Resistance to anthelmintics is becoming a big problem for sheep farmers around the world and should be
addressed very quickly to help prevent its further development. In South Africa, 96% of farm samples tested
showed resistance to at least one anthelmintic product, while barbers pole worm (
Haemonchus contortus
)
resistance is now common in many countries.
Production Animal
Column
FOR ANIMALS. FOR HEALTH. FOR YOU.