Cassava_as_Livestock.pdf - Cassava as Livestock Feed in Africa Proceedings of the IITA\/ILCA\/University of Ibadan Workshop on the Potential Utilization

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Unformatted text preview: Cassava as Livestock Feed in Africa Proceedings of the IITA/ILCA/University of Ibadan Workshop on the Potential Utilization of Cassava as Livestock Feed in Africa S. K. Hahn, L. Reynolds and G. N. Egbunike EDITORS International Institute of Tropical Agriculture International Livestock Centre for Africa Cassava as Livestock Feed in Africa Proceedings of the IITA/ILCA/University of Ibadan Workshop on the Potential Utilization of Cassava as Livestock Feed in Africa 14-18 November 1988 Ibadan, Nigeria S.K. Hahn, L. Reynolds and G.N. Egbunike EDITORS International Institute of Tropical Agriculture Ibadan, Nigeria International Livestock Centre for Africa Addis Ababa, Ethiopia About IITA The goal of the International Institute of Tropical Agriculture (IITA) is to increase the productivity of key food crops and to develop sustainable agricultural systems that can replace bush fallow, or slash-and-burn, cultiva tion in the humid and subhumid tropics. Crop improvement programs focus on cassava, maize, plantain, cowpea. soybean, andyam. Research findings are shared through international cooperation programs, which include training, information, and germplasm exchange activities. IITA was founded in 1967. The Federal Government of Nigeria provided a land grant of 1,000 hectares at Ibadan, for a headquarters and experimental farm site, and the Rockefeller and Ford foundations provided financial support. IITA is governed by an international Board of Trustees. The staff includes around 1 80 scientists and professionals from about 40 countries, who work at the Ibadan campus and at selected locations in many countries of subSaharan Africa. IITA is one of the nonprofit, international agricultural research centers currently supported by the Consultative Group on International Agricultural Research (CGIAR). Established in 1971, CGIAR is an association of about 50 countries, international and regional organizations, and private foundations. The World Bank, the Food and Agriculture Organization of the United Nations (FAO), and the United Nations Development Programme (UNDP) are cosponsors of this effort. © 1992 International Institute of Tropical Agriculture Oyo Road, PMB 5320, Ibadan, Nigeria Telephone: (234-22) 400300-400318 Telex: 3 1 4 1 7 or 3 1 1 59 TROPIB NG Fax (INMARSAT): 874-1772276 V ISBN 978 131 072 3 Contents Preface v Acknowledgments vl I Introduction S.K. Hahn 3 n Utilization of Cassava Cassava in African farming and food systems: implications for use in livestock feeds F.I. Nweke and H.C. Ezumah m An overview of traditional processing and utilization of cassava in Africa S.K. Hahn 16 Utilization of cassava in nonruminant livestock feeds O.O. Tewe and G.N. Egbunike 28 A review of ruminant responses to cassava-based diets O.B. Smith 39 Effect of protein deficiency on utilization of cassava peel by growing pigs E.A. Iyayi and O.O. Tewe 54 The use of cassava for feeding rabbits T.A. Omole 58 The potential of cassava peels for feeding goats in Nigeria O.J. Ifut 72 Varietal Improvement of Cassava Cassava varietal improvement for processing and utilization in livestock feeds J.E. Okeke The adoption of improved cassava varieties and their potential as livestock feeds in southwestern Nigeria M.O. Akoroda and A.E. Ikpl IV 7 Processing of Cassava Processing cassava for animal feeds G.B. Oguntimein Constraints and projections for processing and utilization of cassava S.O. Onabowale ill 85 89 103 1 12 V Cassava Utilization in Selected Countries COTE DWOIRE The use of cassava In broiler diets in C6te d'lvoire: effects on growth performance and feed costs T.O. Tiemoko KENYA Evaluation of cassava as energy source in dairy cow concentrate feeds in Kenya IJL Sanda and J.N. Methu TANZANIA Processing and utilization of cassava as livestock feed in Tanzania F.P. Lekule and S.V. Sarwatt LIBERIA Cassava production and utilization in Liberia S. Ravindran and D. Kenkpen VI 121 127 135 142 Reports of Working Groups and Workshop Recommendations Reports of working groups 1. Feeding cassava to ruminants 149 2. Feeding cassava to nonruminants 151 3. Processing technology of cassava to animal feed 153 Workshop summary and recommendations 155 List of participants 1 57 iv Preface The workshop on "Processing and utilization of cassava by smallscale farmers in Africa" was organized jointly by the International Institute of Tropical Agriculture (IITA), the International Livestock Centre for Africa (ILCA), and the University of Ibadan, Nigeria, at IITA from 8 to 1 1 March 1988. The workshop was funded by the International Development Research Centre (IDRC). Its main objective was to explore avenues for utilizing cassava and its by-products as livestock feed in Africa. The workshop was well-attended by animal scientists, agronomists, and feedmill managers who all exchanged views on the subject and shared their experiences, particularly on the use of cassava for feeding animals in Africa. At the meetings, workshop participants centered their technical contribu tions and discussions on the following themes: • Roles of cassava in African farming and food systems • Processing cassava for human food and livestock feed • Utilization of cassava as food and livestock feed • Potentials and impacts of cassava improvement • Development and implementation of future strategies for improved cassava processing and utilization, particularly as livestock feeds in Africa. Following the presentation of the technical papers, three special working groups were set up to find out the limitations and potentials of cassava use in livestock feeds, to examine existing technologies for processing and utilization of cassava for livestock feeds in Africa and identify research gaps, and to formulate future research strategies and action plans. It is hoped that the publication of the contributions of the workshop participants will increase awareness ofthe public and private sectors about the limitations and potentials of cassava as livestock feed in Africa, and also encourage wide interest and further research efforts in the development of improved processing technologies for utilization of cassava in livestock feeds on the continent. S. K. Harm Director Emeritus International Institute of Tropical Agriculture Ibadan, Nigeria Acknowledgments In acknowledging the various forms of support which contributed to the success of this workshop, a special debt of gratitude is owed to the Interna tional Development Research Centre (IDRC), Canada, for sponsoring the workshop, and to both ILCA and the University of Ibadan, Nigeria, forjoining forces with IITA to organize and hold the workshop. The excellent leadership provided by Professor G.N. Egbunike in the organization of the workshop is particularly appreciated. In producing this volume of proceedings, editorial processing and graphic design work was carried out by staff of the Publications Unit of IITA, while printing was paid for and executed at ILCA. The technical support of both institutes. IITA and ILCA is gratefully acknowledged in making available this volume and thereby fulfilling theworkshop's largergoals ofincreasing awareness of the subject. vi I Introduction Introduction S.K. Hahn Animal scientists, agronomists and feedmill managers have exchanged views and two international centers, ILCA and IITA, have shared their knowledge and experiences at this workshop on production and utilization of cassava as livestock feed, which was held in the interest of national agricultural research systems and industrialists engaged in the production of animal feeds in Africa. Cassava is one of the most important staple food crops grown in tropical Africa. Because of its efficient production of cheap food energy, year-round availability, tolerance to extreme ecological stress conditions, and suitability to present farming and food systems in Africa, it plays a major role in efforts to alleviate the African food crisis. Traditionally, cassava tuberous roots are a major source of carbohydrates in human diets and are processed by various methods into numerous products utilized in diverse ways according to local customs and preferences. In some cultures, the leaves are also consumed as a favorite green vegetable. Many traditional foods processed from the roots and leaves of cassava thus constitute the major part of a family's daily food. However, cassava is frequently denigrated because its roots have a low protein content. But unlike the roots that are essentially carbohydrate, cassava leaves are a good source of protein and vitamins which can provide a valuable supplement to the predominantly starchy diets and feed. Cassava leaves are rich in protein, calcium, iron, and vitamins, comparing favorably with other green vegetables generally regarded as good protein sources. However, while the vitamin content of the leaves is high, the processing techniques used can lead to huge losses. Boiling of the leaves especially may reduce vitamin C substantially. Cassava contains the cyanogenic glucosides, linamarin and lotaustralin. Aftertissue damage, these are hydrolyzed by the endogenous enzyme linamarase to the corresponding cyanohydrins. Further hydrolysis to hydrogen cyanide is responsible for the chronic toxicity associated with inadequately processed cassava products. Therefore, processing procedures must seek to reduce the cyanide in cassava before use. Various processing methods have been used to reduce cyanide quite effectively. For example, grating, sun-drying, boiling and fermenting can reduce cyanide considerably. Aerobic fermenting meth ods which are commonly used in many parts ofAfrica also increase the protein content of the final product by introducing molds to cassava tuberous roots. In collaboration with national programs, IITA has developed high yielding, stable cassava lines, and many national cassava improvement programs in Africa have released Improved cassava varieties resulting from ITTA's work. Higher productivity Is therefore expected from these improved varieties and production technologies. As a result, a surplus Is anticipated that could lower the farm prices of cassava products. This has led to a growing Interest among government authorities and researchers in Africa on the improvement of processing and utilization of cassava and development of new or alternative uses and products. Research strategies in national and international research Institutes have focused mostly on preharvest activities. However, the future of cassava depends largely upon the development of improved processing technologies and of improved products that can meet the changing needs of urban people and on its suitability for alternative uses such as animal feeds and as industrial raw materials. The limited supply of raw materials for the livestock feed industry has resulted in a continuous Increase in the cost of production, causing a phenomenal rise in the unit cost of livestock products. Thus, these products have become too expensive for the majority of the population. The principal future market for cassava is as livestock feed. Cassava has long been recognized by researchers in Africa as an appropriate animal feed and it has been used as an important and cheap feed in many European countries. Both roots and leaves are usable as livestock feed. Cassava offers tremendous potentials as a cheap source of feed energy for livestock, provided it is well-balanced with other nutrients. There is a great deal of current Interest in the supplemental feeding of livestock with cassava in Africa. Traditionally, cassava is fed to sheep and goats In the tropics and it can constitute 20-40 percent of compound livestock feeds, especially in poultry and pigs, with considerable reduction in production costs. However, there is a need to increase available knowledge of technology of utilization of cassava as livestock feed. I believe that one limiting factor in using cassava as livestock feed is the lack of awareness about Its potential and relevant technologies. The objectives of this workshop are, therefore, to: 1 . Collate Information on traditional African processing technologies with emphasis on cassava as a livestock feed, 2. Review the marketing and economics of cassava by-products, 3. Recommend strategies for future research and development on the pro cessing and utilization of cassava as a livestock feed, and 4. Disseminate up-to-date information on cassava. On behalf of the organizing committee, I would like to express sincere appreciation to the International Development Research Centre (IDRC) of Canada, particularly Dr Kategile, for sponsoring this Important joint work shop. Utilization of Cassava Cassava in African Farming and Food Systems: Implications for Use in Livestock Feeds F.I. Nweke and H.C. Ezumah Farming systems can be broadly defined to include the food system as a subset in the overall context of production of food and shelter materials. The food system may also be defined to include crop and livestock production systems as a subset when it is considered as a continuum of activities starting from production through processing and distribution to utilization of crop and livestock products for food. The importance of the latter definition is under scored by the decision, in 1987, to award the first General Foods World Food Prize, as follows: The concept ofthe total food chain lies at the heart ofthe General Foods World Food Prize, for each link in that chain plays a vital role. Every aspect of the production, processing and distribution of food needs to be considered, including farming, the agricultural sciences, food sciences and technology, nutrition, economics, technology transfer, governmental policies, transpor tation and distribution and education [General Foods 1987]. The General Foods' definition is adopted in this paper and livestock production systems as subsets of food systems. This paper will describe the role of cassava in the food crop production systems of tropical Africa. We will also explore the degree to which tropical African countries can meet their cassava needs for human consumption and generate a surplus for use In livestock feeds. In collaboration with International Center for Tropical Agriculture (CIAT), Colombia, the Overseas Development Natural Resources Institute (ODNRI), and national agricultural research systems (NARS) in Africa. IITA has em barked on a continent-wide survey of cassava in Africa. The survey is called the Collaborative Study of Cassava in Africa (COSCA) and it is initially concentrated In six countries namely, C6te d'lvoire, Ghana, Nigeria, Tanzania, Uganda, and Zaire, selected partly on the basis of the importance of cassava in the farming and food systems of the countries. The survey data were analyzed on the basis of production projections using time series data provided by USDA as well as other secondary data. Cassava in food crop and livestock production systems The interrelationships between crop-based production systems and livestockbased systems are illustrated in figure 1, which shows a complex eastern Nigeria system, in which the family household is the major source of labor used for food crop and livestock production. Market * Labor manure Household .... —►> , i Food construction materials ' V Labor feed Meat Eggs t i i Animals Cassava crop Other tree crops crops Feed *■ Goat Sheep Pigs Poultry Composit pen Mulch 4 Manure i i Fertility i Figure 1 : Compound farms/refuse i. »■ Feed ' Interaction of crop and animal farming in a cassava-based system (adapted from Lagemann 1977) In this food crop system, cassava is commonly intercropped with early maturing annuals such as maize, and vegetables like okro, egusi and bitter leaf. The crops intercropped with cassava in different parts ofAfrica vary with regions of growth and food preferences. In Zaire, the intercrop may be dominated by grain legumes such as groundnuts and phaseolus beans, while in Sierra Leone, The Gambia, Liberia, and Guinea, rice is the dominant intercrop. Protected trees like Parkia, and nonwoody perennials such as plantains and bananas, are also frequently grown in patches or as individual stands in cassava fields. While cassava and associated crops are the main food crops, trees provide fuelwood and construction materials. Dry cassava peels are fed to goats and sheep, and pigs eat the tubers. In some countries, cassava leaves are consumed by humans and also fed to animals, or used as poultry rations. These animals provide the household with eggs and meat for consumption and the market. Animal wastes are incorporated with household refuse as mulch and used for soil enrichment or are carted directly into fields, especially those close to homes. Some existing cassava cropping patterns modified to incorporate only two crops are illustrated in figure 2. Pattern 2 is common in Zaire and some countries in West Africa while pattern 4 is dominant in West Africa. Sub8 o . «™diUo™l Cropping pattern. i- ^^^~y — r^ Cbwpea ^ *s* ' . ^Cawpea ^^ S^ Green maize — i...i....-.i >y< ..i — ii . i - -"^ j» ' _. w^ Cassava >^r Soybean yT „ ^7~Slaize -y^r 77*~ J^l J I I I I I I I I I I I I I I I I I LJ JFMAMJJASoNDJFMAM.IJAS Figure 2: I L ond Cassava cropping patterns and alternative patterns for humid southern Nigeria sidiary crops associated with these patterns may be fruits and leafy veg etables. Patterns 1 and 3 are further modifications of the traditional, complex crop mixture systems to nearly monocrop pattern (1) and a completely monocrop pattern (3). Soybean may be intercropped with cassava as in patterns 1, 2 or 4. Cassava is highly compatible as an intercrop with these annuals because of its slow initial growth, especially between planting and six to eight weeks of growth. The annuals which grow faster during the initial growth phases rarely compete adversely with cassava and have been shown to smother weeds. The advantage of soybeans, a relatively new crop in cassava growing areas of Africa, is that it will supply the deficient protein component to a predominantly cassava diet in both human food and animal feeds. Cassava in food systems during crisis The role of cassava in food systems will depend on what happens to real income. Cassava is a crisis crop. In times of war, drought or low national incomes, cassava consumption increases relative to alternative food staples such as yam, maize, rice, and wheat. Cassava in certain forms Is a low income consumers' staple. Although an individual may not increase the quantity of cassava consumed in a year, as national income declines, annual average cassava consumption per person increases because more people begin to substitute cassava for more expensive alternative food staples. Between 1973 and 1985, the annual compound population growth rates varied from 2.7% in Ghana to 4.3% in Cote d'lvoire while the per capita GNP was -3.1% for Ghana and -1.1% for C6te d'lvoire (table 1). 9 Available consumption figures show that per capita consumption of cassava was Increasing in the COSCA countries during the same period (figure 2, table 2). The weighted annual average per capita consumption of cassava increased by 5.66kg from 49.01kg during 1976-80 to 54.67kg during 198185, representing an increase of 12 percent. In Nigeria, the annual average per capita consumption of cassava appears to have declined by 6% from 103.24kg during 1976-80 to 96.55kg during 1981-85. National incomes did not decline at a rapid rate before 1980. In addition, during 1979-83 the rate offood grains import was high. The Nigerian naira was overvalued so that the consumer price for the imported food grains was therefore highly subsidized. During 1980-83, there was a high incidence of cassava mealybug, and during 1985-88 there was a serious outbreak of cassava mosaic and bacterial blight, which caused considerable scarcity of cassava in Nigeria. In 1985, the importation of food grains was banned and by 1986 the Nigerian currency was devalued so t...
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