Comparative Efficacy of Albenzazole, Levamisole, Rafoxanide and Ivermectin Against Naturally Acquired Gastrointestinal Nematodes in Goats

Abstract

A study of the efficacy of 4 antihelmintics was carried out using a faecal egg count reduction test (FECRT) in 105 goats on breeding farm at Ol'Magogo, Naivasha, Kenya. The goats were randomly assigned to 7 groups; received 5.0 mg kg body weight albendazole (ABZ), 15 mg kg levamisole (LEV) 15 mg kg rafoxanide (RAD) orally as 2 doses 24 hours apart and 0.2mg kg Ivermectin (ivm) once orally. Other groups received albendazole and levamisole (ABZ + RAF) at the same doses and schedules as before. Faecal egg counts were measured at treatment (day 0), at 10 and 14 days afterwards. Decreasing efficacies, s measured by 3 different formulae were recorded at day 14 for IVM, ABZ and ABZ +LEV (>96%), LEV (<54%), RAF (<60%) and LEV + RAF (<65%). Calculations of 95% confidence limits indicated that resistance was present in the LEV, RAF and LEV + RAF groups. The predominant use of levamisole on the farm for a long period of time at dose rated recommended for sheep may have contributed to the development of resistance.