Further studies in the control of ovine fascioliasis by strategic dosing.

Three hill sheep flocks were used to study the effect of the strategic use of rafoxanide to kill liver flukes before they attained the adult egg-laying stage. The programme ran from 1973 to 1976. In November 1976 the programme was stopped in one flock but was continued in the other two, which were subsequently merged. The results of frequent whole flock monitoring since 1976, described here, showed that in both flocks the level of infection, as judged by the examination of faeces for the presence of Fasciola hepatica eggs, remained at a very low level. It is postulated that the adoption of a strategic dosing programme over a period of three to four years would limit egg deposition on pastures close to eradication levels and that several years without needing to use anthelmintics against liver flukes would ensue.