Chemotherapy of paramphistomosis in cattle

Controlled tests were used to assess the efficacy of anthelmintics against immature paramphistomes, predominantly Calicophoron calicophorum, in 127 calves which were exposed to contaminated pasture for 7 weeks, treated and slaughtered. When a combination product of oxyclozanide and levamisole was used, oxyclozanide at 18.7 mg/kg reduced parasite numbers in the small intestine, abomasum and rumen-reticulum by 61 to 96.1%, 50.0 to 92.6% and 56.5 to 98.1%, respectively. When 2 doses were given 3 days apart, oxyclozanide was 99.9%, 100% and 100% effective, respectively, in the above organs, and produced improvement in clinically affected calves. This treatment elicited transient diarrhoea. Hexachlorophene at 20 mg/kg as a single dose was 99.5%, 100% and 100% effective against the fluke in the small intestine, abomasum and rumen respectively but severe neurological signs were seen in some calves. Niclosamide at 160 mg/kg given as single or 2 doses 3 days apart was 91.1% and 92.6% effective, respectively, against the parasites in the small intestine. No toxicity was noted. Closantel, at 7.5 mg/kg was not effective. Oxyclozanide and niclosamide when given as a single treatment had varying activity. Two doses of oxyclozanide and a single dose of hexachlorophene gave consistent results. Further tests based on reduction of faecal egg counts, 10 to 14 days after treatment were conducted with oxyclozanide and hexachlorophene against mature paramphistomes in 207 cattle. Oxyclozanide as a single dose or 2 doses 3 days apart at 12.8 to 18.7 mg/kg was 93.6 to 97.5% effective in reducing egg counts. Hexachlorophene at 20 mg/kg was 83.0% effective.(ABSTRACT TRUNCATED AT 250 WORDS)