Parasitic diseases have been noted as one of the major constraints to livestock productivity (Biu et al., 2006) causing enormous economic losses through morbidity and mortality (Waruiru et al., 2001). The direct losses caused by these parasites are attributed to acute illness and death, premature slaughter and condemnation of some animal parts at meat inspection. Indirect losses include the diminution of productive potential such as decreased growth rate, weight loss in young growing calves and late maturity of slaughter stock (Hansen and Perry, 1994).
Infections with parasitic helminths represent a significant economic and welfare burden to global livestock industry. The increasing prevalence of anthelmintic drug resistance means that current control programmes are costly and unsustainable in the long term (Van Dijk et al., 2010). Another factor of increased disease and production loss due to helminths is treatment failure, which is being reported even more frequently. Sustainable control of helminth infections requires detailed knowledge of these factors. There is a need to devise new, sustainable strategies for the effective control of helminthoses (Jackson and Miller, 2006) as frequent and widespread use and misuse of current control methods has resulted in the emergence of resistant parasite populations, such that anthelmintic resistance is now a major global problem, (Kaplan, 2004), and is the greatest threat to the sustainable control of helminthoses (Familton et al., 2001; Sangster and Dobson, 2002; Sutherland and Leathwick, 2010).