The efficiency of diamphenethide in controlling natural infestations of Fasciola hepatica in lambs.

The activity of diamphenethide against natural infestations of Fasciola hepatica in fattening lambs was assessed on a farm with a noted history of fascioliasis. The main experimental groups, two treated and one control, grazed known contaminated pastures for a twelve week period after which they were removed to fluke-free areas to await slaughter. Three groups of four tracer lambs were each grazed for three successive four week periods with the main flock to determine continuity of infection. A single treatment with diamphenethide at 110 mg/kg bodyweight given when the sheep were removed from the trial area was 96.7% effective against the sub-chronic disease which had developed by this time. Three treatments at 110 mg diamphenethide/kg bodeweight given at intervals of four weeks during the grazing period proved to be 100% effective in preventing the establishment of the disease. Significant benefits in terms of weight gain were exhibited by the treated lambs.