Abstract

Helminthosis and helminths resistance to anthelmintic is a great concern in the management of sheep. The efficacy of three different anthelminthics was studied in sheep. Three groups of sheep comprising seven animals each were treated with three different anthelmintics (albendazole, ivermectin and levamisole). Faecal samples were collected from each group before and after treatment. The faecal egg count (FEC) was monitored for 20 weeks using the Modified McMaster Technique. Baseline FEC indicates that all animals used for this study were heavily infected with (mean FEC of 1,779, 1,186 and 1,457 epg for groups A, B and C respectively) high worm burden before treatment. Following treatment, there was reduction in the mean FEC in groups A and C which lasted for three weeks and in group B which lasted for twelve weeks before re-infestation. An increase in FEC in group A (albendazole) treated sheep necessitated the need for re-treatment on week eight. Likewise, the increasing number of FEC in group C (levamisole) treated sheep also led to re-treatment on week nine. Group B (ivermectin) received no second treatment as there was a reduction in the FEC. This showed that the gastrointestinal nematode in the sheep within the study area was more susceptible to ivermectin over time when compared to the albendazole and levamisole treatment. This study also showed the ability of the sheep to mount immune response leading to the fluctuation in FEC observed in the study. A cost-benefit analysis conducted, showed that the cost of treatment of one group of sheep annually using albendazole, ivermectin and levamisole is ?50,310, ?19,762.5 and ?48,750 respectively. This shows that ivermectin is more efficacious and cheaper for the treatment and control of gastrointestinal nematodes of sheep compared to albendazole or levamisole in the study area.

Key words: Albendazole, cost-analysis, efficacy, ivermectin, levamisole, sheep.