Van Wyk, Jan Aucamp; Bath, Gareth F.; Gerber, H.M.; Alves, Regina M.R.; Verwoerd, Daniel Wynand
(Published by the Government Printer, Pretoria., 1990)
A strain of Trichostrongylus colubriformis from Nottingham Road, in Natal, was found to be solidly resistant to levamisole and morantel at the recommended dose levels. Untreated control sheep in fact harboured fewer worms ...