01992naa a2200349 a 450000100080000000500110000800800410001910000190006024500670007926000090014652010290015565000180118465000200120265000180122265000210124065000170126165000100127865000100128865000180129865300290131665300180134565300140136365300320137770000140140970000220142370000180144570000170146370000200148070000160150070000220151677301040153815209782023-08-07       1985    bl uuuu     u00u1 u    #d1 aEDWARDS, J. R.  aA survey of drench resistance in sheep.h[electronic resource]  c1985  aSheep worms which are resistant to chemical drenches have been detected with increasing frequency in Western Australia's south-western farming areas between 1977 and 1980. These worms have anthelmintic resistance and such genetic 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 by using a combination of drenching programme changes and sheep management practices. It has been estimated that drench resistance alone could cost the State's sheep industry $4 million to $6 million a year in lost production, and, as this survey shows, there is potential for far greater costs if resistance continues to increase.  aAnthelmintics  aDrug resistance  aEndoparasites  aNematode control  aParasitology  aSheep  aOvino  aParasitologia  aControle anti-helmintico  aEndoparasitos  aNematodeo  aResistance to anthelmintics1 aWROTH, R.1 aCHANEET, G. C. de1 aBESIER, R. B.1 aKARLSSON, J.1 aMORCOMBE, P. W.1 aROBERTS, D.1 aDALTON-MORGAN, G.  tJournal of the Department of Agriculture. Western Australia. Series 4gv. 26, n. 2, p. 47-51, 1985.