During the past two decades or so, rural population in Africa has increased slowly while urban population has grown dramatically. The hugely increased urban demand for cereals and pulses (which produce crop residues for livestock) and for livestock products is now the main force stimulating mixed farming systems in the semiarid and subhumid areas of subSaharan Africa. Grazing land has diminished, crop residues are becoming a more important element in raising livestock and fattening penned livestock has become profitable.