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9.1 Feed management systems

The traditional extensive system of livestock rearing which pervades most of the livestock sub-sector in sub-Saharan Africa limits the ability of the producer to input supplemental feeding for rearing stock. Only when market opportunities exist, particularly during festivities, do livestock farmers attempt to input supplemental feeding. To ensure stable productivity however, it is critical to practice supplemental feeding even in such extensive systems. The problem of dry season feeding creates a major need for this during such periods as when herbage availability is very low and in some instances non-existent. Pastoralists transport their stock, particularly cattle, mainly on hoof to more humid areas and in desperation to feed stock usually trample on crop farms devastating large hectarage. On such routes, it is usually cassava alone that is found to be still green at such times and hence trampling and feeding on the leaves usually destroy them. A large number of communal clashes, which have been fatal have occurred and is increasing in frequency due to population pressure on land. Cassava by-products, particularly peels from human food industries, sieviates from food and starch industries, leaves and tender stems of cassava can be dried and stored for sale to livestock farmers on transhumance movements to the more humid zones. Supplemental feeding with cassava by-products will also be of tremendous value in settled smallholder or large-scale enterprises where the demand for such feeds increase tremendously during the drier season of the year. The usual phenomenal increase in price of wheat offal during dry seasons in Nigeria is related to the need for large quantities of this as supplemental feed.

Livestock in sub-Saharan Africa and cattle, sheep and goats in particular depend largely on pasture from rangelands. In addition to acute shortage in the drier season, the quality of forage is usually highly fibrous and of a very poor nutritional value. Such roughages therefore need to be supplemented particularly with energy sources for their efficient utilization and improved productivity of stock throughout the year. Cassava storage roots and residues in the form of peels and sieviate from food and starch industries can serve as readily available sources of energy particularly in partial or totally sedentary systems as has emerged with cattle pastoralists in recent times. The feeding of cassava and cassava residues needs however, to be properly synchronized with that of forage to take advantage of the high degradability of cassava in ruminant rations.

While the poultry and pig populations on the continent are traditionally managed to a large extent, pig and poultry enterprises show the greatest promise presently for commercial, intensive production systems. Cassava root is used in dried or fresh forms on small- and medium-scale pig farming enterprises with such pig farmers depending largely on cassava grown on their farms and supplementing their supplies with cassava purchased from neighbouring farms and cassava wastes from homestead processing of cassava into human foods. Scavenging poultry only depend occasionally on cassava wastes from household food processing of storage roots. For commercial feed milling, ruminant feed accounts for only 5 percent of production in Nigeria. Feed for commercial poultry on the other hand accounts for over 90 percent of total feed production while for pigs the proportion can be up to 3 percent (Tewe, 1997).

Cassava root meal can replace all of the maize in pig and poultry rations provided it is balanced with nutrients in which it is deficient and its dustiness is controlled. Pelletizing is recommended to enhance intake and nutrient utilization. Dried cassava leaves can be used to enhance nitrogen and carotene content of such compound feeds.

Cassava production systems need to explore the use of drought resistant, dual purpose varieties with high foliage yields and greenability of leaves to enable harvesting substantial quantity of leaves in addition to storage roots in mixed farming systems and in the production of cassava root and leaf composite meals and pellets for commercial feed millers. Cropping system strategies to increase the foliage and storage root yield per unit land area also need to be put into place.

9.2 Processing and utilization

The objectives for processing of cassava for livestock feeding include:

- extending the shelf life of the crop for safe storage;
- ease of handling and marketing;
- improvement of the acceptability and palatability of cassava-based diets; and
- maximizing the nutritive component and reducing toxins and contaminants.

Solar drying appears the most practicable and economic means of extending the shelf life of cassava products. The moisture content should not exceed 14 percent and can be stored in jute bags or milled and stored in sealed polythene bags for future use.

Shelf life in room temperature for cassava flour is four to five months, while chips can be stored for up to eight months (Ravindran and Kenkpen, 1992). Pellets last between eight to twelve months depending on if they are soft or hard pellets. Nigeria's major feed millers store chips for not more than three months to guarantee freedom from microbial infestation particularly for commercial poultry feeds.

In processing cassava into pellets, differentiation needs to be made for production of soft pellets suitable for farm or domestic usage and hard pellets suitable for large-scale industrial and export markets. Pellets confer the advantage of reduction in volume during transportation and reduction in dustiness of cassava products. Hard pellets also have the advantage of adequate heat treatment with resultant gelatinization of starch and improved utilization in animals. It is noteworthy that locally fabricated manually and motorized pelletizers used at the IITA in collaboration with the University of Ibadan, Nigeria have not addressed the issue of hardness of pellets and its effects on storability and utilization. Pellets exported to the European Union from Indonesia and Thailand are usually sprayed with oil to reduce dustiness. The cassava is also unpeeled in most instances thus reducing cost of processing. Moreover, starch residues are thus incorporated reducing the cost of final pelletized products.

Improvement in acceptability of cassava diets requires a reduction in dustiness and heat treatment of its starchy components. Cassava root flour-based diets should be mixed with oil seed concentrates like full fat soybeans to reduce dustiness. Pelletizing takes care of both factors. It is important to differentiate between pelletizing of cassava meal and pelletizing cassava-based feeds. The latter will entail steaming and pelletizing all feed components including cassava while the former involves only pelletizing of the cassava and its products. The need to reduce cost of pelletizing cassava to enhance its competitiveness in the domestic and export market is critical. Methods whereby cassava chips are first milled and then steamed before production of pellets might be more expensive than pelletizing crushed and dewatered root and or leaf meals directly before drying. Standards for chips and pellets imported into the European Union as shown in Table 38 indicate levels of hydrocyanic acid of not more than 100 ppm. Level of aflatoxin tolerable is 0.05 mg/kg or less.

The unit operations in processing cassava to animal feeds include chipping, grating, shredding, fermenting, drying, pelletizing and packaging. Fermentation is optional depending on the cyanide content of the raw material used. Pelletizing is also not common in domestic usage of livestock feeds. Wilting of cassava leaves is desirable in the feeding of ruminants. Short-term wilting (three to four hours) of cassava leaves gives toxic levels of HCN, but 48 hours wilting is safe.

The level of contaminants and toxins in cassava products can be very important in cassava chips produced as this varies with the period of drying and cleanliness of the environment. Methods of drying as developed by the Post Harvest Unit of IITA recommend optimum chip size (3 x 7 mm) and loading capacity (5 kg/m2) on clean concrete floor which can reduce moisture content from 60-70 to 13-14 percent a day during the dry season. Shredding of cassava storage roots and leaves and constant turning can ensure drying to less than 14 percent in 72 hours during the wet season. There is however, a need to test this under varying environmental conditions.

9.3 Marketing of feed and livestock products

The price competitiveness of cassava products as a replacement for maize or wheat in livestock feeding remains the major bottleneck to its widespread adoption in domestic and export markets. Experience from South Africa shows the feasibility of using modern agronomic techniques with supply of inputs under contract arrangement to produce cassava at US$20/tonne as compared with an average price of US$50/tonne with traditional cultural practices in Nigeria. The reduction of production cost is therefore primary to expanding the market for cassava usage in the livestock industry. Farm gate processing is also important to reduce transportation costs thereby transporting dry chips and pellets rather than the fresh storage roots, which also deteriorate rapidly between harvesting and transportation to processing sites. Processing whole unpeeled storage roots into animal feeds will reduce the cost of peeling. A study by Tewe and Bokanga (2001) showed the price of cassava products from unpeeled storage roots and leaves to be 40 percent cheaper than maize.

The poor storability of dried cassava products also limits its usage to short periods when prices are competitive and cassava is produced in abundance. Chips are stored for not more than three months by commercial feed millers in Nigeria. Extending the shelf life will allow its procurement and storage when prices are low and can be competitively used with escalating prices of maize.

The need for promotion of appropriate cassava-based formulations, processing technologies and livestock husbandry systems to optimize performance and profitability of cassava-based feeds in different agricultural settings for mixed (crop/livestock) and livestock farmers in sub-Saharan Africa cannot be over-emphasized. Escalating prices of livestock products in the last decade have been largely due to scarcity and astronomically spiralling costs of livestock feed ingredients, which constitute between 60 and 80 percent of cost of production in commercial livestock production systems. Cheaper cassava-based feeds can therefore stem this tide of animal protein scarcity and its chronic deficiency on the continent.

9.4 Policy issues

Cassava is at different stages of transformation in countries of sub-Saharan Africa. While it is still a staple food in most countries, it is presently a cash crop for urban consumption and food export notably in Ghana and Nigeria. To shift cassava to being a livestock feed for domestic and export markets, the policy issues which need to be implemented are as follows:

Diffusion of information on cassava-based feed formulation and on-farm data on performance of livestock and fish reared on these diets need to be widely disseminated and demonstrated on the continent. Technologies of incorporation of cassava leaves into feeds also need wide dissemination. Developing the bulking system and collection centres for cassava supply to industries is seriously hampered by poor rural infrastructure. There is a dire need for improvement of rural roads and transportation systems in most sub-Saharan African countries. Development of information technology is critical in accessing market information locally and globally. Cassava farmers therefore need the Internet connectivity to enable them to take advantage of domestic and export market opportunities.

The erroneous notion that cassava is a women's crop has been recently debunked by Nweke et al. (2002). Cassava needs to be seen as a crop that provides opportunity for poverty alleviation for both men and women. Indeed as cassava becomes industrialized both men and women become visible in the mechanized production and processing scene. It is therefore necessary to take a holistic approach and introduce modern systems for production and processing of cassava to drive down its cost and affect its competitiveness with cereals in the livestock feed industries of sub-Saharan Africa.

9.5 Capacity building

The history of cassava development in Africa shows the dearth of scientific capacity that has spanned the period between 1935, when cassava research began at the Amani Research Station in United Republic of Tanzania, and the present in different research and development centres of the continent. The lack of incentives and serious under-funding of most research stations on the continent had dampened the enthusiasm of the few researchers committed to cassava development. Yet, due to the long-term growth cycle of the cassava plant relative to maize, breeding research, in particular, takes a longer time for cassava.

Livestock research and adoption on the continent has also suffered a similar fate. A World Bank Study in Nigeria on the impact of developed livestock technologies on their adoption by farmers (Shaib, Aliyu and Bakshi, 1997) revealed that while there were numerous crop production technologies adopted and disseminated in the 25 years of the World Bank Assisted Agricultural Development Project (ADP) operation in Nigeria, only within the last decade was the issue of livestock technologies addressed to a limited extent. The rate of adoption of developed livestock technologies was also disastrously low. Similar stories were obtained in most other African countries operating the World Bank Assisted ADP scheme.

Due to the low ratio of extension agents to farmers on the continent coupled with under-funding of extension services, poor rural roads and mass illiteracy, development of human capacity for cassava production, processing and marketing has been greatly hampered. Capacity building for cassava development on the continent must therefore take cognisance of the need for researchers, extensionists and practitioners i.e. cassava farmers and processors and would be industrialists. The need to institute private-led initiatives in capacity building is underscored by recent experience in South America where the CLAYUCA consortium serves as an arrowhead for private-led initiatives in cassava development. The need to target cooperative farmers and processors of cassava in capacity building is also critical to its industrialization.

9.6 Environmental considerations

Traditional processing of cassava into food in sub-Saharan Africa is often associated with the discharge of large amounts of water, hydrocyanic acid and organic matter in the form of peels and sieviates from pulp as waste products. These are often improperly disposed and when they are carried out on a large-scale, as in commercial 'garri' production, the resulting wastes are often left in mounds which generate a highly offensive odour and are rather unsightly. Cassava processing is therefore generally considered to contribute significantly to environmental pollution and depletion of water resources as they contaminate surface water particularly during the dry seasons of the year.

Traditional cassava processing in Africa is usually carried out around homesteads and closely associated with rearing of sheep, goats, chickens and at times pigs. These stocks therefore consume a substantial part of these wastes in the form of peels, sieviates and often leaves. Indigenous stock reared around homesteads therefore, helps to reduce environmental pollution from cassava waste. It is also a common sight to find roaming indigenous cattle, sheep and goat aggregating around large mounds of cassava peels in cassava food processing centres consuming some part of the generated wastes. An organized collection of cassava wastes particularly the peels and pulp wastes and their proper processing into dry cassava products, can serve as useful supplementary feed particularly for ruminants in sub-Saharan Africa. Indeed, this is the most practicable form of utilizing cassava for livestock feeding in scenarios where cassava storage roots are still insufficient as human food. Cassava processing into commercial livestock feeding presently involves peeling of cassava storage roots and sun-drying. While the peels are left to rot, the drying of the storage roots into chips does not entail discharge of water, which is removed by solar drying. Hence, the risk of cyanide discharge into surface of water is also eliminated and such processing sights are less unsightly. The more recent introduction of producing cassava chips and pellets from whole unpeeled storage roots with incorporation of leaves (Tewe and Bokanga, 2001) eliminates the problem of waste disposal as unpeeled storage roots and leaves are shredded and sun-dried. This is therefore an environmentally friendly method of cassava processing and reduction of waste disposal problems. It is also important to note that processing of cassava into pellets in Thailand often involves incorporation of pulp wastes particularly from the starch industries. Adoption of this in Africa will help reduce waste in food and starch industries. Moreover, wastes from ethanol industries contain protein rich yeast containing by-products. These are often left to discharge in surroundings of industries using cassava for ethanol production as in Nigeria. These protein rich by-products can serve as very useful complements to energy rich cassava storage roots in rations and supplements for different livestock species if the wastes are properly harnessed through drying and proper storage. Use of cassava by-products for livestock feeding can therefore be a major means of recycling wastes into wholesome livestock feeds in Africa.

The advocacy for the use of cassava leaves as animal feed is challenged by the fact that in cassava production systems the leaves are usually left to rot in the field. In this case, returning leaves and stems to the soil is the essential first step in preventing nutrient depletion and maintaining soil fertility. Indeed, in areas where leaves and stems are utilized and removed from the field, nutrient removal can double or triple, depending on whether it is nitrogen, phosphorus or potassium that is considered (FAO/IFAD, 2000). However, where animal manure is available it is recommended to apply about 5 tonnes/ha manure together with chemical fertilizers high in potassium where chemical fertilizers are not available or too costly, it is recommended to apply 7-10 tonnes/ha of manure in combination with wood ash. Mixed farming systems involving rearing of livestock and cultivation of cassava can therefore be an environmentally friendly and fertility sustaining system as the manure from livestock can be very useful in maintaining soil fertility while the cassava leaves peel and pulp wastes or even the storage roots can serve as valuable livestock feed.

Due cognisance must be taken of the hydrocyanic acid discharge from cassava food processing industries. Sheep and goat drinking from cassava polluted water has resulted in some mortality. It is therefore important to ensure that cyanide that is liberated during cassava processing especially in processes that create large amounts of "squeezed juice" should be diluted or stored in such a manner that cyanide concentration is reduced before discharged into the environment. Indeed, models for utilizing waste water from garri industries presently advocate recycling into starch factories where the residual starch can still sediment and be collected before discharge of the effluent into the environment. It should be noted that considerable cyanide can be lost even if storage of such waste water is for a short time.

9.7 Issues for further research and development

While the paltry use of cassavas for livestock feed in Africa is of concern in the quest to develop this root crop as an industrial raw material, the proportion of waste from cassava production presently generated in some countries calls for a closer study of cassava and exploration of its potentials in such places. The proportion of usage for feed in Cameroon, Madagascar and Uganda surpassed that for Nigeria between 1991 and 2000. Yet, these countries are not recognized for their potential to use the crop for livestock feed. That of Cameroon is more interesting as the use of cassava at 150 000 tonnes annually far exceeds the use of maize, which stands at 5 000 tonnes. The example in Nigeria is much publicized, though its rise from 3 percent usage to 10 percent between 1985 and 1990 and subsequent fall to 5 percent between 1991 and 2000 has little explanation; it is probably due to a combination of factors of policy, competitive price and population of livestock particularly poultry during these periods. The ban on maize in 1984 subsequently popularized cassavas for livestock feeds. However, from 1990 non-competitive prices of cassava and the sharp drop in commercial poultry population from 20 to 8 million reduced usages from 10 to 5 percent between 1991 and 2000. Country studies therefore need to be initiated in these places with some potential as indicated, to further exploit it usage for livestock feeding and understand its dynamics as models for other African countries. Products from cassava-based feeds need to be studied in comparison to maize-based ones in these countries in order to obtain comprehensive information on cassava competitiveness and marketing. A review of policies to enhance competitiveness of cassava as compared with maize also needs to be undertaken in many African countries as cereal importation is still highly subsidized.

Due to the cultural practices for cassava production in most African countries, being produced on small hectarage in traditional farming systems with minimal inputs and implements, the cost of production per tonne is much higher and the volume that can be supplied for industrial usage is rather restricted compared with modern production systems as presently adopted on a 5 000 ha cassava farm in South Africa. For competitive processing of cassava in livestock feeding for domestic and export markets, modern cost and labour saving production methods need to be adopted in sub-Saharan Africa. There is therefore the need to develop such practices. Similarly the development of organized bulking and collection centres to feed livestock and other industries needs to be put into place.

Cassava processing methods for the production of chips and to a lesser extent pellets in sub-Saharan Africa are at stages of infancy. Production of chips is by cutting into slices with cutlass or a sharp knife and sun-drying on bare ground or rocky areas in most instances. The cassava is also usually peeled thus increasing cost of production. The quality of such chips also hardly meets the requirement as indicated for the European Union market and compromises standards for domestic feed milling formulations because contaminants and microtoxins are usually at unacceptable levels. Processing techniques developed particularly in collaborative studies between the IITA and the University of Ibadan need to be introduced for adoption on the continent whereby chippers and shredders are used and hygienic conditions are maintained in drying areas. Use of unpeeled storage roots as in these reported studies will eliminate peeling costs and incorporation of leaves will enhance the protein and carotenoid content of such products.

Pelletized products developed from locally fabricated pelletizing machines are still of inferior quality to those acceptable for export markets as soft rather than hard pellets are obtained and the starch is still rather powdery rather than being gelatinized. Yet the cost of imported pelletizers still remains unaffordable for cassava farmers and processors in most instances. The need to source affordable and suitable pelletizers for acceptable cassava pellet products remains to be addressed on the continent. The process of first producing dried chips before pelletizing still raises the problems of remilling and rehydration before pelletizing. Techniques need to be developed to eliminate the need for drying fresh grated or shredded roots before pelletizing to reduce costs and enhance production efficiency. The need to develop efficient dryers for chip and pellets must also be urgently addressed particularly for climate with considerable wet seasons, which coincide with regions of abundance of cassava.

Cassava chips and pellets from Africa have poor storability as microbial infestations set in within three months of storage in most instances. The prolongation of shelf life for cassava products will expand their use particularly in periods of maize scarcity in the livestock industry. Cassava cyanide 'scare' is still a problem for its adoption in commercial feed milling. Peeling and sun-drying eliminates most of the cyanide to levels below the acceptable 100 ppm in most instances. Methods of chipping and drying as well as variety differences affect this. With the advocacy for use of unpeeled storage roots for production of cassava chips processing methods need to be standardized and rapid; easy methods for cyanide assay need to be disseminated to ascertain acceptable cyanide levels particularly in dry products.

Livestock production systems in Africa are still largely extensive, yet the demonstrable use of cassava for livestock feeding particularly in the European Union is for the intensively reared stocks. Feeding systems to incorporate cassava as a supplement in extensive and semi-intensive systems need to be developed to take advantage of the need for energy supply in the usually malnourished stock of cattle, sheep and goats reared in such systems.

The development and promotion of cassava plant-based formulations for different livestock and fish species in different countries and agro-ecological settings of Africa is a desideratum if cassava is widely adopted in African livestock feeding systems. The manipulation and promotion of the recommended ration will go a long way to impact this.

On-farm feeding trials to evaluate the performance and economic value of such rations need to be carried out extensively on the continent in order to win the confidence of the commercial feed miller and livestock farmer to adopt them. Their wide publicity after adequate testing will enhance its dissemination and adoption. Establishment of pilot projects to demonstrate the feasibility of such cassava-based feeding systems needs to be instituted in different settings to enhance their adoption.

In a report of the global cassava strategy plan, Spencer et al. (1992) commented on the African continent thus:

"Industrialists and entrepreneurs often shy away from using cassava in their applications because of the absence of a local example to follow and uncertainty of success".

Africa therefore needs catalysts which will facilitate cassava feed entrepreneurs and champions who will protect the cassava industry. It is only with this strategy that cassava can take its rightful place in livestock feeding on the African continent.

9.8 Enhancement of food security

Cassava plays a major role in efforts to alleviate the African food crisis because of its efficient production of food energy, year-round availability, tolerance to extreme stress conditions and suitability to present farming and food systems in Africa. In spite of net food importation in Africa as from the early 1970s and food production growing at half the population growth rate from 1970-1985, cassava production in Africa has increased tremendously in the last four decades with Africa producing half of this and Nigeria replacing Brazil as the leading cassava-producing country in the world.

According to Nweke et al. (2002), the factors responsible for the dramatic expansion of cassava in Africa are:

- the introduction of the mechanized grater and garri preparation methods that have transformed cassava into a dry cereal for urban consumption;

- rapid population growth and poverty which have encouraged consumers to search for a cheaper source of calories;

- high yielding TMS varieties that have boosted farm level cassava yields by 40 percent in Ghana and Nigeria; and

- biological control of the cassava mealybug.

Yet cassava still remains a traditional staple rather than an industrial crop and it is being discouraged as a low protein food rather than focussing on helping smallholders diversify their crops through industrialization and increase rural incomes so that families can purchase protein-rich foods to supplement their diets.

To satisfy these needs, cognisance should be taken of the problem of glut that usually follows bumper harvests of this crop due to it being used almost entirely for traditional human foods. Diversifying the use of cassava into other commodities in its transformation chain requires standard specifications that will make the cassava product compete favourably in domestic and export markets. Yet these standards can hardly be met with farm gate processing as the rural infrastructure and capability on rural farms are grossly inadequate in most African countries. However, only cassava for animal feed stands a chance of it being used on a large scale as an industrial raw material from cassava as the criteria of standards appear not as stringent as those for other industrial raw material commodities. The required equipment including shredders, chippers and dryers can be fabricated to fit into small-scale enterprises near farming communities. Such dried products can then be transported to urban feed millers or other domestic or export markets. Encouraging farm gate processing of cassava will therefore not only reduce the cost of cassava products due to reduced transportation costs but will also guarantee direct earnings to cassava farmers who hitherto have to contend with ridiculously low prices offered by middlepersons who also have to contend with high transportation costs of fresh cassava storage roots to urban markets. Processing of cassava into dried feed raw material will also enable storage, which is not possible with fresh storage roots, unless they leave this in the ground until needed.

Some countries in Africa currently use between 6 and 27 percent of its cassava production for livestock feeding. The proportion used and absence of use in many African countries is related to its non-competitive pricing relative to maize, which is becoming scarce for the industry due to other competing needs. Yet cassava can occupy this gap if its feed products are made cheaper through:

- farm gate processing to reduce transportation costs of fresh storage root from farms;

- introduction of labour saving equipment to enhance volume produced;

- promotion of cost saving technologies such as use of unpeeled whole storage roots which eliminates peeling costs;

- modernizing production of cassava to enhance productivity and reduce production costs.

Processing of cassava into livestock feed components can therefore expand the market for this commodity and eliminate the cycle of glut that usually accompanies cassava production. The ability to carry out these operations at rural farm level will certainly enhance rural income and create agro-based enterprises, which will help in checking the rural-urban migration.

The ability to purchase other food items to complement their predominantly cassava-based diets will certainly promote health, survival and overall food security of the farming populace in sub-Saharan Africa.

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