The efficacy of four anthelmintics against Calicophoron daubneyi in naturally infected dairy cattle.

The paramphistomicidal activity of four anthelmintics in dairy cattle naturally infected by Calicophoron (Paramphistomum) daubneyi was evaluated. Seventy Friesian adult cows were treated at drying-off (19 albendazole; 23 netobimin; 13 closantel and 15 oxyclozanide), and 21 remained untreated as controls. The anthelmintic efficacy was determined by estimating the faecal egg count reduction (FECR) values for each of the anthelmintics. The reduction in the number of cows shedding eggs in the faeces was also estimated. The C. daubneyi egg-output was not fully suppressed following the administration of any of the parasiticides. The FECR values ranged from 0% to 26% in the cows receiving albendazole or netobimin, with 11-39% of cattle becoming negative after therapy. Better results were achieved with closantel and oxyclozanide, with FECR values of 97-99% and CPCR (cattle positive by coprology reduction) percentages of 85-93%. The observation of a similar efficacy with closantel and oxyclozanide against C. daubneyi led us to recommend the administration of closantel in those countries where oxyclozanide is not available.