Anthelmintic resistance of gastrointestinal nematodes in goat farms in Guadeloupe (French West Indies)

Abstract

Faecal egg count reduction tests after anthelmintic treatment have been conducted on 1057 goats belonging to 19 farms located in various climatic zones of Guadeloupe. Five anthelmintics were used at 1.5 to 2 times the recommended amounts for sheep: fenbendazole, albendazole, febantel, tetramisole and ivermectin. In all the farms, nematodes were resistant to benzimidazole derivatives. Three nematode genera were involved: Haemonchus which prevailed and was the most resistant, Trichostrongylus and Oesophagostomum. Tetramisole and ivermectin were by and large highly efficacious. The onset of resistance to ivermectin was suspected in one farm only. Tropical climatic conditions, suitable for nematode development, speed of reinfestations, excessive frequency of treatments made with the same compound used over a long period of time and animal trading between farms may have contributed to the selection of resistant nematodes in Guadeloupe.