Livestock Research for Rural Development 20 (1) 2008 | Guide for preparation of papers | LRRD News | Citation of this paper |
The study was carried out during the period from December 2005 to May 2007 in the mixed crop-livestock farming systems of Jimma zone to assess the overall responsibility gender in livestock production and management system. The survey methodology employed was a systematically purposive sampling using structured questionnaire. PRA tools were applied to complement data collected by questionnaire. The smallholder livestock production systems considered in the study area is mixed crop–livestock farming.
Livestock are significant in maintaining the livelihoods of their keepers by providing food, draught power, manure, skin, hide, cash, security, social and cultural identity, medium of exchange and means of savings. There is a distinct, but not very strict, gender division of work in the farming systems. This division of labor is influenced by socio-cultural and socio-economic factors. Men are largely the decision makers for livestock production and are in charge of general herd management. However, women generally contribute more labour inputs in areas of feeding; manage vulnerable animals (calves, small ruminants, and sick, injured and pregnant animals), cleaning of barns, dairy-related activities (milking, butter and cheese making), transportation of farm manure and sale of milk and its products than men and children. Men own most of the livestock species and put up for sale animals and meat. Women own a small proportion of the large animals as well as chicken and are milk managers in the small holder system. Both men and women take part in the harvesting and transportation of feed, chaffing of fodder, feeding of animals, cleaning of sheds and sale of milk, cheese and butter. Processing of milk is done solely by women while children of both sexes tether and herd animals. Constraints to livestock production such as lack of capital and access to institutional credit, competing use of time, poor technical skills and lack of access to improved extension services affect women more than men, and may further limit the participation of women and their efficiency in all-purpose livestock production. Overall, research on gender responsibility in livestock is limited, especially gender disaggregated data on work sharing, access to resources and benefits.
Key words: decision making, division of labour, gender division of work
Gender, the sexual distinction between male and female, has commonly been used interchangeably with sex, within the academic fields of cultural studies, gender studies and the social sciences the term "gender" refers to a social construction rather than a biological condition (Reddy 2005).
It is nearly three decades since 1970 called into question if women and men benefited equally from economic development. Since then, gender issues in agriculture have become an important subject of inquiry. Gender is a socio-economic variable used to analyze roles, responsibilities, constraints, opportunities and incentives of people involved in agriculture (Poats 1991). Although the involvement of women in livestock production is a long-standing tradition all over the world, but livestock patterns differ widely among ecological zones, and socio-political systems (Niamir 1990).
Smallholder livestock production system in mixed crop–livestock farming refers to livestock production that takes place in arable areas or areas with arable potential in the business of subsistence system (Payne 1990). It is usually practiced in semi-arid, sub-humid and humid agro ecological zones of the world. Crop production both for subsistence and cash generation is the major activity of this system, with livestock playing a supportive role (Jahnke 1982).There is a strong linkage within the system between crop and livestock production. Crops provide by-products and unmarketable surpluses which livestock convert into high value products. Livestock help clear stubble, trample wet fields, and provide manure and draught power for cultivation. In these systems livestock serve as living banks for capital accumulation and provide milk and proteins. The system is labour-intensive, with some dependence on capital and land (rented, share-cropped or owned), and is receptive to new technology (Camoens 1985). Partial or total confinement is the common livestock management technique. Sources of animal feed are farm-grown pastures, crop by-products and residues, grasses around settlements, communal grazing lands, cut-and-carry feed from forest and irrigated canals and concentrates. These mixed farming systems are common in the highlands of eastern (Ethiopia, Kenya, parts of Uganda and Tanzania) and central (Rwanda, Burundi and parts of the former Zaire) Africa, in a large part of Asia and in the Andean region of Latin America (Jahnke 1982; Sere et al 1996).
The role of women in livestock production is not documented in Jimma zone in general. On the other hand, women constitute a greater proportion of the population economically involved in agriculture. No information is used for gender analysis and is rarely used for development planning in Jimma zone. Despite their considerable involvement and contribution, women’s role in livestock production has often been underestimated or, worse, ignored. Gender-blindness is partly the result of a paternalistic bias, but also of the attitudes of women themselves, who may have been conditioned by their culture and society to undervalue the worth of the work they do. As a result, it is very difficult to obtain information on the role of women in livestock production from existing research and project reports. In addition, women’s work is not well reflected in national statistics in Ethiopia; women’s productive labour is not differentiated from their reproductive work; their contribution is undervalued, thus losing the value of ‘work’ and becoming merely an ‘activity’.
Gender analysis, in the mixed farming systems, is required to understand the various roles of men, women and children in farming systems and the way these roles are affected by new interventions (FAO 1979). Particular attention is normally given to the roles of women because in many cases they undertake major responsibilities in agricultural production, processing and marketing in addition to performing household chores, and reproductive and child rearing activities. Research for technology generation, testing and adaptation often requires long periods and passes through several stages. When and how gender analysis is considered in the research process may depend a great deal on the nature of the technology being studied and the overall research approach used Therefore, the specific objectives of this study were to:
Jimma Zone, found in South Western Ethiopia, lies between 360 10´ E longitude and 70 40´ N latitude at an elevation ranging from 880 m to 3360 meters above sea level (Dechassa, 2000). Very currently Jimma Zone is divided in to 16 Weredas/districts (hosting a total population of over 2.4 million; CSA, 2004) with an agro-ecological setting of highlands (15%), midlands (67%) and lowlands (18%) (Dechassa 2000). Farmers in the area practices mixed crop-livestock agriculture. The zone is one of the major coffee growing areas of southwest Ethiopia; cultivated and wild coffee is a main cash crop of the area.
Jimma zone is well endowed with natural resources contributing significantly to the national economy of the country. Major crops grown, other than coffee, are maize, tef (Eragrostis tef), sorghum, barley, pulses (beans and peas), root crops (enset-false banana and potato) and fruits. Tef and honey production are another sources of cash after coffee. Enset (Ensete ventricosum) is a strategic crop substantially contributing to the food security of the zone and is especially important in Setema and Sigimo weredas (highlands) (CSA 2004). According to JZMSR (2004), the climate is humid tropical with bimodal heavy annual rain fall, ranging from 1200 to 2800 mm. In normal years, the rainy season extends from February to early October. The thirteen years mean annual minimum and maximum temperature of the area was 11.3 oC and 26.2 oC, respectively. The soil type of the study area is characterized with black to red soils.
Reconnaissance survey was conducted to
have the notion of understanding about the study area and to select the
representative study sites before to get on questionnaire. Different
participatory rural appraisal (PRA) tools and purposive sampling design were
used to collect data. Data was collected from December 2005 to May 2007. Primary
data were collected through personal interviews by trained enumerators using a
survey questionnaire covering measures from resources to parameters reflecting
farm functioning from one hundred and nineteen households with at least one
ruminant and monogastrict livestock at the time of survey.
The statistical analysis showed that in Jimma zone men headed most of the households (93 %).There is the likelihood of gender bias as men would make the important production decisions. The household characteristics in the district are summarized in Table 1. Most of the respondents were middle aged (45.62). There were a relatively larger number of children per household (10.57). Children contributed significantly to household labour in livestock production. There highest values in household sizes could be due to polygamous marriages.
Table 1. Summary of household characteristics in kersa district |
|||||
Characteristic |
N |
Minimum |
Maximum |
Mean |
Std. |
Age status of respondents |
119 |
18.00 |
70.00 |
45.65 |
18.60 |
Number of children in household |
119 |
4.00 |
25.00 |
10.57 |
4.54 |
House hold size |
119 |
12.00 |
27.00 |
13.91 |
3.04 |
N = number of respondents; Std= standard deviation |
The main motivation for smallholder livestock production in Jimma zone was for subsistence. Livestock production system is completely traditional and they retain almost all of the grain for home consumption and some produce hay but no one is trying to produce silage. Income was a relatively strong motivational factor; however, income and subsistence are carried equal weight. An out of the ordinary feature in the study area was that farmers were not involved in production of livestock feed.
The study showed variations in the mean distribution of livestock ownership per household by gender. The general pattern (Table 2) showed that men owned more cattle, sheep, goats and equine; on the other hand, small animals like chicken were mainly owned by women compared to men. This could be due to the fact that women lacked capital to purchase them. There was consensus among rural women the reason why they could not buy livestock was that men controlled all cash obtained from crop production. About 60.5% (N=72) of the respondents told that livestock ownership by gender is decided by man. However, ownership patterns of livestock are more complex and are strongly related to the social and cultural factors (Table 2).This zone is located in a predominantly cattle raising region of southwest Ethiopia. This means that promoting poultry production there is likely to benefit women more than it is likely to benefit men. The results also indicate that there was small equine (horse and donkey) and goat population. The respondents justified fewer preferences of people to Equine. As of adverse cultural practices in Jimma people is not in a position to raise goats. On top of that goats browse their cash crops, chat (Catha edulis) and coffee (Coffee arabica). Even some households consider goats as Satan.
Ownership of land is often related to ownership of the larger animals. However gender related question is that how can a woman own a livestock while the land she uses belongs to her husband? This question has also risen by researchers in Jimma in general and Ethiopia in particular illustrates the strong influence of cultural and traditional aspects. On the other hand in Jimma area, even if a married woman has not signed the ownership contract or pays for a cow unlike in Tanzania (FAO 1998), the animal still belongs to the husband and even in case of divorce, and the wife cannot take the animal with her. The perception of these cultures implies that with marriage all the belongings of the women, including her, revert to the ownership of men. However, in similar animal husbandry systems in Pakistan, women continue to own the animals they brought as a part of their dowry. They can decide by themselves what to do with them, but if they want to sell livestock, then they need the men's agreement (FAO1998; Reddy 2005). The situation is also similar in jimma. Thus, even if women are the rightful and legal owners of livestock, they still depend largely on decisions and agreements made by men. In Jimma those animals controlled by men even if women are the owner are held as an investment for savings and, therefore, are an important source of prestige.
In terms of sale management and income generated from livestock, more than 55% of the respondents enlightened that selling of live stock and its products is done mainly under willingness of men, however, involvement of both men and women on decision making for sale is only 10.9% (Table 3). Generally, men's control over livestock resources tends to occur with women’s and to increase with age.
Table 2. Mean livestock ownership disaggregated by gender |
|||||
Species of livestock |
N |
Minimum |
Maximum |
Mean |
Std |
No. of cattle owned by men |
119 |
3.00 |
7.00 |
4.47 |
1.25 |
No. of cattle owned by women |
119 |
1.00 |
3.00 |
1.86 |
0.60 |
No. of chicken owned by men |
119 |
0.00 |
12.00 |
5.54 |
3.65 |
No. of chicken owned by women |
119 |
5.00 |
10.00 |
9.29 |
1.66 |
No. of sheep owned by men |
119 |
1.00 |
4.00 |
2.23 |
0.78 |
No. of sheep owned by women |
119 |
0.00 |
2.00 |
0.89 |
0.45 |
No. of goats owned by men |
119 |
0.00 |
2.00 |
0.99 |
0.56 |
No. of goats owned by women |
119 |
0.00 |
1.00 |
0.16 |
0.37 |
No. of equine owned by men |
119 |
0.00 |
1.00 |
0.26 |
0.44 |
No. of equine owned by women |
119 |
0.00 |
0.00 |
0.00 |
0.00 |
N = number of respondents; Std= standard deviation |
Gender is an important element in labor share in mixed crop–livestock production systems in Jimma. Both men and women do a large number of tasks related to animal production, with some degree of variation in involvement from district to district. These tasks include chaffing of fodder, herding, feeding, milking of animals, cleaning of cattle sheds, harvesting and transportation of feed (green grasses/weeds, fodder, forages etc.), and sale of live animal and animal products through formal and informal channels.
In Jimma zone milk processing is primarily the work of women. About 74.8% of the respondents put in the picture that dairying is mainly task of women. Children of both sexes have also playing a significant role in milking animals while men make decisions about breeding and marketing of animals (Table 3). Similar studies done by Whalen (1984) in the highlands of Ethiopia revealed that women are more involved in livestock production than in crop farming. They clean cow sheds, milk the cows, look after calves and sick animals, cut the grass and supervise feeding and grazing of cows, make dung cakes, butter and cheese and sell these products once or twice a week. Women distribute the milk to different users. Men feed the oxen and take the animals for veterinary treatment when need arises.
Culture and tradition define most of women’s roles in the agricultural sector in Jimma. In most cases in Jimma zone, their role as primary caregivers may limit the time women have to spend on non-reproductive activities including livestock production. Women in the agricultural sector are heavily involved in home production activities, which involve childcare, food preparation and carrying of water and fuel.
In this particular study in Jimma zone of Ethiopia a quantity of woman working time hours were investigated. In view of that, the average daily amount of time women spend on livestock-related activities are: 30 minutes in milking, 1.25 hours in cleaning the barn, 1.80 hours in collecting and transporting dung, 2.15 hours every other day in processing milk, 3 hours a day on childcare, 4 hours on food preparation and 1.30 hours fetching water. The same study noted children spending an average of 8 hours a day herding and watering animals and collecting dung. The wife of the head of the household does simpler tasks such as separation of milk, processing and sale of butter and cheese. The daughters-in-law undertake the harder and more difficult jobs such as caring for small ruminants, milking, watering stock, feeding and tethering of animals. Sale of milk within the farming community is seen as the inability to feed children, but the disposal of milk in the form of gifts is acceptable. The family consumes most of the butter and women sell cheese and surpluses of butter. Men decide on the purchase and sale of cattle and maintain contacts with co-operatives and the veterinary department.
In the Jimma zone of Ethiopia, the important factors that influence the gender division of labor in livestock production are the distance where the animals are kept, significance and the size of the area being farmed. Women are involved in all cattle-farming tasks if the animals are kept in the farmyard; larger farms do not involve women in these tasks. The more valuable the animals, the smaller the possibility that women will make decisions on their purchases and sales. If the animals serve a purpose which is in the women’s realm of responsibilities, e.g. feeding the family, her influence on decision making is greater than with animals that fulfill purely farming purposes, such as draft oxen.
In the study area, women and men are involved in livestock production, but compared to women; men have easier access to technology and training, mainly due to their strong position as head of the household and greater access to off-farm mobility. Official livestock services are often controlled by men and extension personal are primarily men who are not accustomed or trained to teach technical subjects to women. Extension programmes and educational materials are mainly designed by and oriented towards men.
Differentiation of activities in livestock husbandry mainly executed by women and by men and possibilities to increase productivity through training; cultural and social constraints to participation of women in public life and extension; existence and structure of other production support services including other projects; constraints to mixed training groups; gender disaggregated adult literacy level; time and mobility are constraints of women. Since training could balance between the development of technical and methodological skills, and creating a social awareness for putting gender strategies into action, still to increase productivity in livestock production, training should be oriented towards those persons directly involved in these activities.
In Jimma, men have easier access to government provided credit than women. 70.6% of the respondents believed that men have better access to school. Women are rarely considered creditworthy because they have no collateral. In addition, they often cannot read and write, and are not used to frequent governmental or official institutions without their husbands consent and being accompanied (Table 3).
Efforts to introduce new technology which does not take into account existing knowledge of men and women are unlikely to meet with success. Failure to direct information to the person responsible for a given activity may result in no increase in productivity or even in stock losses. Credit lines have to respond to client's needs and their social and cultural values. Social behavior and traditional rules of men and women have to be well considered and credit lines adapted to their special needs.
Official livestock and extension services; gender disaggregated information on following items: participation in decision making structure; type of services and training offered and attended; other sources of information and training (rural radio, TV); literacy level; participation in formal and informal groups.
In Jimma zone, livestock husbandry is being practiced for food, fiber, work power, manure cash income and other agricultural uses since time immemorial, yet livestock raising is primarily a subsistence activity to meet household food needs and supplement farm income. According to the survey result 49.6, 40.3% and 10.1% of the respondents assured that livestock are source of food, cash and manure, respectively (Table 3). Livestock also plays important role in maintaining the livelihoods of the farmers by providing social and cultural identity, medium of exchange and means of savings and investments. But in jimma zone food security through livestock keeping can be influenced in three ways: a) Direct use of products like meat, milk and milk products, eggs, 2) Using the income from milk, manure or animal sale to buy food, and 3)Using manure to improve household food production like vegetable and other food crop production.
The demand for livestock products is rapidly increasing with rise in population, household income and change in food tastes and preferences. Unfortunately, role of public sector for increasing livestock productivity is limited as compared to crop sector. Therefore, the private sector is generally encouraged to invest in production, processing and marketing of livestock and livestock products.
Contrary to crops, animal products, such as eggs and milk, are produced throughout most of the year. Selling them provides a small but continuous income, which is more likely to be reinvested in nutrition than the income of selling a cow or a cash-crop. Generally, increased livestock production can have a positive influence on the nutritional level and the well-being of household members. Increased income from livestock production may change the intra-household distribution and control over products and earnings. When higher production and marketing activities become more important, women often lose their control over products and income. The level of nutrition within the family may decrease if the animals from which the products are derived are sold and the earnings spent on personal necessities, without taking into consideration the household well-being.
Although, livestock is important sources of livelihood for millions of smallholder farmers in developing countries, condition is similar in jimma zone, but their productivity remains low (Akhter et al. 1995). The low productivity is explained by both biological and socio-economic constraints. Constraints such as unavailability and high cost of exotic breeds and commercial feed, lack of market access and unstable livestock and livestock product prices, and access to veterinary services and drugs are gender neutral. Studies in the field indicate that there are some obstacles like lack of capital and access to institutional credit, workload and lack of technical skills and access to extension services that may affect women more than men. Factors such as low literacy level, sex stereotyping of roles and socio-cultural factors, e.g. early marriages, seclusion, childcare and other reproductive chores obstruct women from getting access to productive resources.
Table 3. Gender role in traditional livestock production systems in kersa district |
|||
Parameter |
Gender |
Frequency |
Percent of respondents |
Which animal to keep? |
men |
90 |
75.6 |
|
women |
17 |
14.3 |
|
both men and women |
12 |
10.1 |
Selling produce |
men |
15 |
12.6 |
|
children |
33 |
27.7 |
|
women |
71 |
59.7 |
Income expenditure |
men |
82 |
68.9 |
|
women |
34 |
28.6 |
|
Both men and women |
3 |
2.5 |
Ploughing and crop sowing |
men |
75 |
63.0 |
|
children |
33 |
27.7 |
|
women |
11 |
9.2 |
Harvesting |
men |
23 |
19.3 |
|
children |
39 |
32.8 |
|
women |
49 |
41.2 |
|
all family |
8 |
6.7 |
Cooking and water fetching |
men |
21 |
17.6 |
|
children |
6 |
5.0 |
|
women |
92 |
77.3 |
Child care |
children |
15 |
12.6 |
|
women |
40 |
33.6 |
|
both children and women |
64 |
53.8 |
Herding management |
men |
26 |
21.8 |
|
women |
14 |
11.8 |
|
children |
79 |
66.4 |
Animal feed preparation |
men |
26 |
21.8 |
|
children |
37 |
31.1 |
|
women |
56 |
47.1 |
Milking |
children |
30 |
25.2 |
|
women |
89 |
74.8 |
Barn cleaning |
man |
10 |
8.4 |
|
children |
26 |
21.8 |
|
woman |
62 |
52.1 |
|
5.000 |
21 |
17.6 |
Seek animal management |
man |
14 |
11.8 |
|
children |
8 |
6.7 |
|
woman |
76 |
63.9 |
|
5.000 |
21 |
17.6 |
Selling produce |
man |
15 |
12.6 |
|
children |
33 |
27.7 |
|
woman |
71 |
59.7 |
Animal ownership |
male |
72 |
60.5 |
|
women |
35 |
29.4 |
|
children |
12 |
10.1 |
Animal holding trend |
increasing |
20 |
16.8 |
|
decreasing |
92 |
77.3 |
|
no change |
7 |
5.9 |
Decision making for sale of produce |
men |
66 |
55.5 |
women |
40 |
33.6 |
|
Right and access to information, school ,capital and Land ownership |
man |
88 |
73.9 |
women |
24 |
20.2 |
|
both |
7 |
5.9 |
|
Access to trainings on livestock husbandry practices
|
Men |
89 |
74.8 |
Women |
30 |
25.2 |
|
Role of livestock in the livelihood
|
Source of food |
48 |
40.3 |
Source of cash |
59 |
49.6 |
|
Source of manure |
12 |
10.1 |
It is important to make a distinction among the types of responsibility that women have over livestock: ownership, control over decision-making, use rights and provision of labour. In most systems, women provide labour for the various tasks related to livestock but may or may not control the process of decision-making, particularly over the disposal of animals and animal products. Similarly, women may be involved in production, but may or may not own the means of production: livestock, land, water, etc.
Husbands (men) and wives (women) both usually have a say over the use of resources, although there may be "unequal, often conflicting claims on resources for the satisfaction of basic needs" (Shumaker 1991). Men’s ownership rights over animals are guaranteed by a near universal set of inheritance rules that are gender biased and rooted in religion and patriarchal kinship systems (Dahl 1987). Women in general have less access to the means of production in comparison with the extent of their labour contribution.
Another common, but by no means always applicable, result of increased women’s workloads is that women may be constrained to take short-cuts in animal production and management strategies, even though they know what normally should be done to prevent or diminish environmental problems. Anything that requires a lot of labour, such as taking animals to distant pastures or splitting herds, will be cut back.
Traditional rural markets are not only places to shop or sell but also places to exchange information. Women’s involvement in rural markets is little understood and inadequately researched, particularly in terms of the facilities that women use, their price responsiveness and their dependence on barter or cash. Women are less familiar with modern markets and feel powerless to influence them. They are hampered by cultural norms, and the lack of access to information on new technology, prices, demand, etc. Unlike their husbands, they are rarely given training in modern small-business management. Also they are hampered by factors common to all: lack of adequate transport and communications services, inadequate equipment and facilities in marketplaces (e.g., cold storage, stalls) and the presence of exploitative middlemen.
Akhter S K, Banu S , Sarker N J , Joarder R I and Saha R R 1995 Women in farming and income earning: Study of a Gazipur village. Journal of Rural Development Bangladesh 25(2):79–98
Camoens J K 1985 Asian livestock production and management systems. In: Camoens J K, McDowell R E, de Boer A.J, Wimaladharma K P, Bawden R J and Moog F A (editors), regional workshop on livestock production management. The proceedings. Asian Development Bank, Manila, the Philippines. pp. 3–35
CSA (Central Statistical Authority) 2004 CSA (Central Statistics Authority), 2004. The 2001/02 Ethiopian Agriculture Enumeration (EASE), Executive Summery, May 2004, Addis Ababa, Ethiopia
Dahl G 1987 Women in pastoral production. In: Dahl G (Editor). The realm of pastoral women. Ethnos 52(1–2):246–280
Dechassa Lemessa 2000 Field Assessment Report: Jimma Zone of Oromia Region, UN-Emergencies Unit for Ethiopia
FAO (Food and Agriculture Organization of the United Nations) 1979 Women in food production, food handling and nutrition with special emphasis on Africa. Food and Nutrition Paper 8. FAO, Rome, Italy. 223 p
FAO (Food and Agriculture Organization of the United Nations) 1998 Rural women and food security: current situation and perspectives. Rome http://www.fao.org/DOCREP/003/W8376E/W8376E00.HTM
Jahnke H E 1982 Livestock production systems and livestock development in tropical Africa. Kieler Wissenschaftsverlag Vauk, Kiel, Germany. 273 pp
JZMSR (Jimma Zone Meteorology Station report) 2004 Ten year’s calamite data. JZMS. Jimma, Ethiopia.36.pp
Niamir M 1990 Herder’s decision-making in natural resource management in arid and semi-arid Africa. Community Forestry Note 4, FAO, Rome
Payne W J A 1990 An introduction to animal husbandry in the tropics. 4th edition. Tropical agricultural series
Poats S V 1991 The role of gender in agricultural development. Issues in Agriculture 3. CGIAR (Consultative Group on International Agricultural Research), Washington, DC, USA. 63 p http://www.worldbank.org/html/cgiar/publications/issues/issues3.pdf
Reddy Gayatri 2005 With Respect to Sex: Negotiating Hijra Identity in South India. (Worlds of Desire: The Chicago Series on Sexuality, Gender, and Culture), University Of Chicago Press (July 1, 2005).
Sere C, Steinfeld H and Groenewold J 1995 World livestock production systems: Current status, issues and trends. FAO Animal Production and Health Paper 127. FAO (Food and Agriculture Organization of the United Nations), Rome, Italy. 82 p http://www.fao.org/wairdocs/LEAD/X6101E/X6101E00.HTM
Shumaker J 1991 Planning women’s projects. WilD (January/February) Heifer Project International, Little Rock, Arkansas
Whalen I T 1984 ILCA’s Ethiopian highlands programme: Problems and perspectives in expanding the participation of women. Paper prepared for IITA/ILCA/Ford Foundation workshop on Women in Agriculture in West Africa, Ibadan, Nigeria, 7–9 May 1984. 24 p
Received 17 September 2007; Accepted 18 October 2007; Published 1 January 2008