Malan, F.S.Gerber, H.M.Alves, Regina M.R.Bigalke, R.D.2014-11-172014-11-1720141987Van Wyk, JA, Malan, FS, Gerber, HM & Alves, RMR 1987, 'Two field strains of Haemonchus contortus resistant to refoxanide', Onderstepoort Journal of Veterinary Research, vol. 54, no. 2, pp. 143-146.0330-2465http://hdl.handle.net/2263/42607The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Two field strains of Haemonchus contortus, one from Pretoria on the Highveld and the other from White River in the Lowveld of the Transvaal, showed pronounced resistance to rafoxanide at a dosage rate of 7,5 mg/kg live mass per os. Both of these strains originated from kikuyu pastures under irrigation. Resistance in South Africa to rafoxanide and other anthelmintics, namely, closantel, ivermectin and the benzimidazoles is reviewed. It is concluded that apart from avoiding farming practices where integrated worm control is not possible, there is at present no solution to the problem of worm resistance in the country.en©ARC - Onderstepoort and Faculty of Veterinary Science, University of Pretoria (original). ©University of Pretoria. Dept. of Library Services (digital).Veterinary medicineVeterinary medicine -- South AfricaArticle