Swan, Gerry E.Harvey, R.G.2010-12-202010-12-201983-12Swan, GE 1983, 'Persistent anthelmintic effect of ivermectin in cattle', Journal of the South African Veterinary Association, vol. 54 , no. 4, pp. 249-250. [http://www.journals.co.za/ej/ejour_savet.html]0038-28097102127047I-7222-2013 http://hdl.handle.net/2263/15447The persistent anthelmintic effect of ivermectin given subcutaneously at 200 µg/kg was evaluated against induced infections of Haemonchus placei, Ostertagia ostertagi, Cooperia pectinata, C. punctata, Bunostomum phlebotomum and Oesophagostomum radiatum in cattle. Forty-four Friesian bull calves raised under worm-free conditions were restrictively randomized to one untreated control group and 3 ivermectin treated groups of equal size according to mass. Animals in the different treated groups were treated either 9, 7 or 5 d before infection, which was induced in all animals on the same day. Nine days after treatment the effect of ivermectin was virtually undiminished against O. ostertagi and B. phlebotomum and 7 d after treatment against Cooperia spp. Counts of all worms were reduced by 99% or more following the treatment given 5 d before infection. According to the non parametric method, 80% efficacy in 80% of the treated animals were achieved against all 5 worms up to 7 d after treatment and against O. ostertagi and B. phlebotomum up to 9 d after treatment.enSouth African Veterinary AssociationBunostomum phlebotomumPersistent anthelmintic effectIvermectinHaemoncus placeiOstertagia ostertagiCooperia pectinataCooperia punctataVeterinary helminthologyArticle