Mixed farming systems, in which crops and livestock are integrated on the same farm, are the backbone of small-scale agriculture in most developing countries (Lenné and Thomas, 2006). Crops and livestock contribute in a diversity of ways to enhancing the livelihoods of the poor through provision of food, income, draught power and employment. Livestock are a major source of high-quality protein, minerals, vitamins and micro-nutrients for developing country populations and livestock-derived food items contribute significantly to agricultural GDP. Animals also play a major role in improving food security in such countries, because cash income obtained from the sale of animals is regularly used to buy non-livestock food items and inputs to farming. It is predicted that the demand for livestock products in developing countries will increase substantially over the next 25 years (Delgado et al., 1999). Failure to meet the challenge of further growth in the livestock sector in these regions is likely to result in the growing urban demand for livestock products being met by subsidized imports. This will be to the detriment of small-scale producers and national and regional economic growth.