Of a total annual production of 87 million tonnes of cassava in Africa, only 6 percent of this is recorded as used in livestock production, mainly in traditional systems for sheep, goats, pigs and chicken reared around homesteads where cassava is processed into food. Commercial usage is limited to poultry and to a lesser extent pig rations. Usage decreases with high cattle density per caput and increases with high commercial poultry density.
Fresh roots contain 60-65 percent moisture, 24-31 percent carbohydrate, 0.2-0.6 percent ether extract, 1-2 percent crude protein and comparatively low content of vitamins and minerals. Dried cassava leaves are a good source of proteins, minerals and vitamins. Recommended nutrient content for cassava chips and pellets for feed are: moisture, 13 percent (max), starch, 75 percent (min), crude fibre, 5.2 percent (max), for peeled roots. Values for unpeeled roots are: moisture, 13 percent (max), starch, 63 percent (min) and crude fibre, 9 percent (max). Tolerable levels of aflatoxin and cyanogens are 0.05 mg/kg (max) and 100 mg HCN equivalent/kg (max) respectively.
Total usage for feed varied in the selected countries from 0-5 percent in West Africa, 0.24-10 percent in Central Africa, 0-27 percent in East Africa and 0-10 percent in South Africa for 2000. No significant change in trend occurred in usage between 1991-2000. In Nigeria an increase from 3-10 percent occurred between 1985 and 1990 but decreased subsequently to 5 percent with the decrease of commercial poultry population from 20 to 8 million between 1985 and 2000 due largely to a raw material feed shortage. Cassava as feed in Cameroon is 150 000 tonnes compared with use of maize, which stands as 5 000 tonnes from 1991 to 2000. Percentage used for feed in East Africa is highest in Uganda at 27 percent. Only Madagascar records cassava usage as feed at 10 percent in South Africa. Wastes from cassava on the continent constitute between 5-52 percent in West Africa, 5-15 percent in Central Africa, 2.7-10 percent in East Africa and 3.1-20 percent in South Africa. This waste is a potential feed resource for the regions.
While research capacity and extension services for livestock development are grossly inadequate on the continent, studies in different countries of Africa confirm the suitability of total replacement of maize or other cereals with cassava root meal in rations for livestock and fish provided there is adequate supplementation with protein, minerals and vitamins, oil supplementation or pelletizing to eliminate dustiness for monogastric feeds, competitive pricing of cassava and reduction in supplementation cost through the use of non-protein nitrogen or poultry manure for ruminant concentrates. Cassava root meal and leaf meals in marsh or pellet form have been used at a 4:1 ratio as maize substitute for poultry and pigs with cost reduction and satisfactory performance. Cassava peels and pulp waste also serve as a readily available energy source particularly for ruminants and to a lesser extent finisher pigs. Cassava usage in commercial feed milling in Africa is largely in the form of dried root chips or marsh as compared with pellets largely used in the European Union. Linear programmed, cost-effective cassava root and leaf meal-based formulations with partial or complete replacement of maize are provided for different livestock and fish species in Africa. A price of between 60-75 percent for cassava products compared with maize is recommended for its competitiveness in feeds.
Competitive pricing of cassava products for feed can be achieved through:
i. reduced processing cost such as use of whole unpeeled storage roots to eliminate peeling costs;
ii. incorporation of wastes including pulp wastes, peels and leaves;
iii. reduced cost and increased efficiency of chipping, drying and pelletizing cassava;
iv. strategic usage for dry season feeding and at periods of maize scarcity;
v. modernizing cassava production to reduce fresh cassava production cost to US$20 per tonne as in South Africa;
vi. steady supply must be guaranteed for export market.
Research and development issues for expanding use of cassava for feed in Africa include:
i. country studies on dynamics of cassava and livestock product trade across seasons;
ii. modernizing cassava production and development of cost effective dryers and farm gate processing to enhance productivity, quality and pricing;
iii. development and promotion of cassava plant-based formulations for livestock and fish in different agro-ecological settings and crop/livestock farming systems of Africa;
iv. establishment of pilot projects to demonstrate feasibility of cassava-based feeding systems.
Environmentally friendly processing techniques to recycle cassava wastes must be adopted and favourable policies such as removal of subsidies on imported cereals will enhance cassava competitiveness and marketing. Expanding cassava usage from its present role of traditional usage for food into a commercial livestock feed raw material is essential to eliminate the cycle of glut (with excess cassava supply), enhance economic empowerment of the continents important rural cassava farming populace and enable them to afford much needed proteineous and other nutrient-rich foods to supplement their predominantly cassava-based diets.