Anthelmintic resistance in nematodes of beef cattle in south-west Western Australia

摘要: Anthelminthic resistance in nematodes of beef cattle is an emerging issue globally with implications for effective parasite control. The prevalence the Mediterranean-style climatic zone south-west Western Australia was assessed on 19 farms, using faecal egg count reduction tests. Pre-treatment worm counts were compared at 14 days after treatments ivermectin (injectable), fenbendazole (oral), or levamisole (oral). A separately grazed group treated topical (pour-on) and sampled 28 included as a comparison against injectable ivermectin. results demonstrate that common, failure least one anthelmintic (<95% each species, by arithmetic means) either major species Cooperia oncophora Ostertagia ostertagi 17 properties. Resistance to (injectable) demonstrated C. 59% tests, but fully O. this route. Conversely, resistant present 50% 67% farms respectively, both oncophora. finding Haemonchus placei several properties unexpected low there no suggestion pathogenic effects. An indication reduced efficacy pour-on formulation apparent ostertagi, may have development, given widespread use reported region. This survey confirms anthelminthic common pattern occurrence general agreement surveys elsewhere other countries.