Background

Helminths (parasites that reside in an animal's intestines) constitute one of the most important constraints to small ruminant livestock production in the tropics resulting in widespread infection in grazing animals, associated production losses, high costs of treatment and death. Current control methods in the tropics focus on reducing contamination of pastures through anthelmintic treatment of animals and/or controlled grazing. But there are problems with increasing frequencies of drug resistance.

An attractive, alternative and sustainable solution is the breeding for disease resistance. Indeed, anecdotal evidence suggests that, among the large and diverse range of indigenous breeds of sheep and goats in the tropics, there are some that appear to have the genetic ability to resist or tolerate helminthiasis. One of these is the Red Maasai breed found in East Africa and perceived to be resistant to helminthiasis. The Red Maasai is a fat-tailed sheep associated with the Maasai tribe found in northern Tanzania and south-central Kenya.