RESUMO
The efficacy of moxidectin 2% oral gel (Equest, Fort-Dodge) against European worm strains was studied through post-mortem worm counts and feacal egg counts (FECs) in 12 young ponies naturally infected. The animals were allocated in two groups of six ponies each: the first one was treated at 0.4 mg/kg b.w. and the second one received a placebo and served as control. All the ponies were necropsied 14 days post-treatment. The efficacy of moxidectin in reducing strongyle FECs ranged from 99.8% to 100% from 3 to 14 days after treatment. Moxidectin efficacy was 100% against Trichostrongylus axei and Triodontophorus spp., > 99.9% against Cyathostomes adults and L5, 92% against S. edentatus L5, 100% against O. equi L5, 99% against O. equi L4, and 92% against G. intestinalis. No animal treated with moxidectin was harbouring P. equorum, Habronema spp., G. pecorum nor G. nasalis, while the control group was slightly infected with these parasites. This experiment confirms the post-mortem worm count results obtained in the United States and the FECs results reported in Europe. Moxidectin showed to be safe in young ponies.