The Efficacy of Dichlorvos (V3 Formulation) against Larval and Adult Oesophagostomum spp. in the Pig

Controlled anthelmintic trials were performed on pigs injected experimentally with 20,000 Oesophagostomum spp. larvae. The efficacy of dichlorvos (Vi formulation*) at a dose-rate of 35mg./kg. body weight given at 42 days after infection was found to be 99·9 %. Values of 41·5 % and 60·5 % were recorded against 2-week-old larvae. The treatment was equally effective against the adult forms of the 2 Oesophagostomum species found in the U.K. On the fourteenth day of parasitic development, however, O. quadrispinulatum appeared to be more susceptible to dichlorvos therapy than O. dentatum.