Efficacy of Commonly Used Anthelmintic in Selected Sheep Farms in Arusha

Abstract

A study was conducted to determine the efficacy of albendazole, levamisole, oxyclozanide and ivermrctin anthelmintics in selected sheep farms in Arusha, northern part of Tanzania. Eight farms under study were screened and in each farm a total of 100 sheep were involved. The sheep were allocated in groups of 25 animals and each group received different anthelmintic. We sampled pre- and post-treatment faecal samples for faecal egg count reduction test. In addition, we incubated the samples for identification of different helminths. Resistance to anthelmintics was assumed to be present if egg count percent reduction was less than 95% and the lower limit of the 95% confidence interval for percentage reduction was equal to or less than 90%. Our results show that all the farms studied had developed resistance to albendazole, levamisole and oxyclozanide and ivermectin with the egg count reduction ranging from 67-87%; 69-87% and 74-90% respectively. The most predominant nematode species in the resistant poputation were Haemonchus and Trichostrongylus.  It was concluded that albendazole, levamizole and oxyclozanide and ivermectin anthelmintics are not effective against some nematode strains of sheep in the studied farms