Abstract

The efficacy and comparative cost analysis of three injectable ivermectin preparations was evaluated in West African Dwarf (WAD) sheep naturally infected with gastrointestinal nematodes. Three anthelmintics: ivomec classic® (IVC), ivomec super® (IVS) and ivomec gold® (IVG) were administered at a dose rate of 200µg/kg to control gastrointestinal nematodes in three treatment groups comprising five animals each. The faecal egg counts (FEC) for each animal pre-treatment, and thereafter for a period of 16 weeks post-treatment was carried out using the modified McMaster technique. The results is a pre-treatment mean FEC for groups A, B and C of 970±550.36, 880± 279.55 and 1640±893.78 eggs per gram (epg), respectively and a mean FEC of zero for all treatment groups one week post treatment. The mean FEC of zero was maintained for 28, 35 and 56 days, respectively. A mean FEC threshold for re-treatment of 500 epg was exceeded at days 42, 49 and 84 for groups A (615±167.26), B (830±287.49) and C (737.5±448.10), respectively. The results were subjected into a deterministic model to estimate the costs of using IVC, IVS or IVG in an annual control program. The costs of a one-time treatment were $20.6, $20.8 and $21.0, respectively. The average annual costs were $82.39, $83.22 and $41.99 for groups A, B and C, respectively. Thus, veterinary service and labour are two variables that contributed more to cost of treatment when compared with the price of drugs and average weight of the animals treated.

Key words: Ivermectin, gastrointestinal nematodes, West African Dwarf sheep, efficacy, cost analysis.