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Evaluation Of The Crack Approach For The Control Of Drench Resistance In Sheep Worms, J R. Edwards, Helen Chapman, Jon Dunsmore

Journal of the Department of Agriculture, Western Australia, Series 4

The Department of Agriculture launched the CRACK approach to worm control in September 1985 in response to finding that anthelmintic (drench) resistant worms were present on 68 per cent of a random selection of Western Australian sheep farms.

The high cost of internal parasites in terms of lost production and drench costs, together with the high prevalence of resistant worms of farms, confirmed that changes were needed to existing parasite control measures in sheep.l

A Survey Of Drench Resistance In Sheep Worms, J R. Edwards, R. Wroth, G. C. De Chaneet, R. B. Besier, J. Karlsson, P. W. Morcombe, D. Roberts, G. Dalton-Morgan

Journal of the Department of Agriculture, Western Australia, Series 4

Sheep worms which are resistant to chemical drenches have been detected with increasing freuency is Western Australia's south-western farming areas between 977 and 1980. These worms have anthelmintic resistance and such genetis resistance puts essential internal parasite control practices at risk.

This prompted veterinarians in the Esperance, Albany, Bunbury, Geraldton and Northam areas to survey farms to determine the prevalence of resistance to drenches and to define those sheep management practices which encourage its development.

This article describes the survey which was conducted to assess the extent of drench resistance, what causes its build-up and how it can be controlled …