摘要：Nearly two thirds of the world’s livestock are found in developing countries, yet their productivity is such that they account for only one third of the world’s meat and one fifth of its milk. In Africa, milk yields are only one tenth of those in North America and Europe (FAO/ILRI, 1995). Both genetic and environmental reasons have been forwarded to explain low animal productivity in sub-Saharan Africa (SSA). Genetic explanations include the “inferiority” of the native breeds, although these breeds often out-survive the imported stock. The main environmental explanation for low productivity is poor animal nutrition arising from overstocking and overgrazing. However, the contribution of overstocking to the low productivity remains ambiguous.
