Efficacy of combined chemotherapy against gastrointestinal nematodes and Fasciola hepatica in cattle.

A controlled trial of the efficacy of several anthelmintic compounds as a combined therapy in the treatment of gastrointestinal nematodes (GIN) and Fasciola hepatica (F. hepatica) in naturally infected cattle was carried out. Twenty crossbred calves, 8-18 months old, were selected for inclusion in the trial based on finding eggs of F. hepatica and GIN in the faeces. They were blocked in four groups of five animals each according to GIN fecal egg counts on day 0. Treatments were sequentially allocated to animals in each block as follows: Group 1 served as non-treated control; Group 2 was treated with netobimin orally at 20 mg/kg; Group 3 received triclabendazole orally at 12 mg/kg and levamisole was applied intramuscularly at 5.5 mg/kg; Group 4 received clorsulon administered subcutaneously (s.c.) at 2 mg/kg and ivermectin s.c. at 200 microg/kg. Six to eight days after treatment the animals were euthanatized in order to collect and identify the parasites. Results showed a reduction of GIN by 87.3, 95.8 and 99.5% in Groups 2, 3 and 4, respectively. The percentage reduction of immature flukes was 0.0, 72.5, and 67.5% and for adult flukes 91.0, 97.5 and 100% for Groups 2, 3 and 4, respectively. Compounds indicated against nematodes showed high efficacy and products directed against F. hepatica acceptably removed adult flukes. However, efficacy against immature stages was generally not satisfactory.