A major constraint on livestock production in developing countries is the scarcity and fluctuating quantity and quality of the year-round feed supply. Livestock are fed mainly on low quality agro-industrial by-products. The addition of foliage from tree leaves or supplementation with seed meals or even urea in the form of urea molasses multinutrient blocks can improve the utilization of low quality roughages mainly through the supply of nitrogen to rumen microbes. This publication presents results from the nutritional component of a project devoted to improving animal productivity and reproductive efficiency. It is an excellent reference for researchers, students and extension workers and it will help them to improve the utilization of feed resources and enhance animal productivity to meet the challenges imposed by the 'livestock revolution' taking place in developing countries.