Livestock constitutes 47 per cent of the agricultural gross domestic product (GDP) and contributes over 12 per cent to total GDP in Kenya. Most of the production is, however, sustained by the arid to semi-arid lands (ASALs), which are estimated to support about 25 per cent of the nation’s human population and slightly over 50 per cent of its livestock. The ASALs cover more than 80 per cent of the land in Kenya and are characterized by low, unreliable and poorly distributed rainfall, and are thus mainly used for extensive livestock production and wildlife. The country can be divided into seven agro-climate zones using a moisture index based on annual rainfall expressed as a percentage of potential evaporation (Sombroek et al, 1982). Areas with an index greater than 50 per cent have high potential for cropping and are designated zones I, II and III. These zones account for about 18 per cent of Kenya’s land area. The semihumid to arid regions (zones IV, V, VI and VII, referred to as ASALs) have indexes of less than 50 per cent and a mean annual rainfall of less than 1100mm. Ninety per cent of the arid and semi-arid areas lie below 1260m and mean annual temperatures range from 22°C to 40°C (Kabubo-Mariara and Karanja, 2006).