WEB Vetnews May 2015

Regulars I Zoetis pages

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

of the worm population live free on pastures and thus

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

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

vet nuus • news

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Mei/May 2015