Abstract

The world population is growing very fast. In 1950 it was 2.5 billion and increased to 5.3 billion by 1990. The projections for 2030 show the world population rising to 8.9 billion. It is therefore a fundamental issue that any intervention involving livestock must be predicated on their synergistic role in benefit of the whole farming system rather than as producers of meat, milk or eggs using feeds which are in competition with human needs. 

The tropics present great opportunities for sustainable development thanks to the enormous cultural and biological riches of these regions. The rational exploitation of local feeds and local breeds of livestock will support much more sustainable production systems in the medium and long term. These have received insufficient attention in the past and have not been considered seriously because of the introduction of "exotic" systems based on high inputs, high technology and "breeds of high genetic merit". As a result, local breeds in many tropical countries have disappeared or their population is decreasing drastically. 

Various studies demonstrate that the appropriate use of local feed resources and indigenous livestock breeds requires close integration between crops and livestock within the system. The excreta is recycled on the farm to produce energy and the effluent is used for fertilizer to produce protein supplements for the livestock. 

A strategy should be developed useful for poor people. They face several problems such as: lack of credit, land, livestock and appropriate technologies or wrong technology transfer, lack of technicians and research according to their reality and priorities and there is lack of people's participation in the development process. 

The complexity of the reality should make scientists think more carefully about the appropriate strategy that will get people out of poverty. Research in Asia of replications of the famous Bangladesh Grameen Bank micro-credit programs show that there is an ideal progression for farm families in the sub-continent, that even the poor aspire too. According to this experience poor women invest in small livestock and the household step by step gets out of poverty. There is a great and unmet challenge for research on local resources to cater to the needs of these people. 

Introduction

The world population is growing very fast (Table 1). In 1950 it was 2.5 billion and increased to 5.3 billion by 1990. The projections for 2030 show the world population rising to 8.9 billion. 

There is a growing disparity between the expanding world population and the earth's food producing capacity, the rate of increase of which is less than the rate of population growth. As a result, food supplies per capita are decreasing (Brown and Kane 1994). However, an important issue here is the role of livestock. As living standards rise, so does consumption of livestock products. But the feeding systems to produce these products, especially in the industrial countries, use the same feed resources as are eaten by humans, namely cereal grains and soya bean meal. It is estimated that almost 50 % of the world grain supply is consumed by livestock (Sansoucy 1995). It has been argued (Preston 1995) that if all the world's grain production was reserved for human consumption then there would be enough to feed the 9-10 billion inhabitants at which point the world population is expected to stabilize. 

It is therefore a fundamental issue that any intervention involving livestock must be predicated on their synergistic role in benefit of the whole farming system rather than as producers of meat, milk or eggs using feeds which are in competition with human needs. 

The tropics present great opportunities for sustainable development thanks to the enormous cultural and biological riches of these regions, the rational exploitation of which could support sustainable production in the medium and long term, but which have not been considered seriously in previous attempts to develop the livestock sector in these regions (Preston and Murgueitio 1994). 

The sustainable use of natural renewable resources will be facilitated when the feed is grown, the animals are fed and the excreta is recycled on the farm in ways that minimize the use of imported inputs including energy. (Preston and Murgueitio 1994). 

If, as expected, fossil fuel prices increase in the long term at rates exceeding average inflation in the industrialized countries, then one increasing role will be the use of livestock as a source of power in agriculture. The other issue, which perhaps relates more specifically to Latin America, and parts of Africa, is that the principal livestock production system is extensive grazing by large ruminants, the establishment of which has mostly been through the destruction of the natural ecosystems of the tropical rain and cloud forests. These systems have consolidated the position of the medium to large landowner/cattle rancher and, by so doing, minimized opportunities for the small scale farmer (Preston and Murgueitio 1994). 

The complexity of the reality should make scientists think more carefully about the strategy. The "ladder concept" (Figure 1) proposed by Todd (1998) shows that, in terms of livestock, there is an ideal progression for farm families in the sub-continent, that even the poor can aspire too. 

The strategy

• Lack of credit
• Land distribution: very little land, tenure, no land
• Very little or no livestock
• High population pressure
• Lack of technology according to the real situation or wrong technology transfer
• Lack of technicians or technicians trained "out of the reality"
• Lack of research according to the reality and priorities
• Lack of participation of people in the development process
• High pressure on natural resources / shortage of fuel

There is now evidence that with the right type of institutional, credit and technical interventions, the poorest households - and especially when the work is routed through women - have tremendous capacity to pull themselves out of hardcore poverty with immediate benefit to the most vulnerable groups, i.e. children under five and pregnant women (Todd 1996a,b). A good example is the "Bangladesh experience" where small scale rural poultry production has lifted millions of women out of absolute poverty (Jensen 1996) as the poultry enterprise gave a 35% increase in household income and family food intake was increased (Jahangir Alam 1997). An example of credit is the Grameen Bank (Village Bank) where the collateral is human responsibility and 95% of borrowers are women and a lot of money is invested in livestock production with repayment rate of 97%. Small animals traditionally are in the care of, and are owned by, the women in the household. Which means when they are sold, even if a man actually takes them to the market, the proceeds come back into her hand, and she decides on the use of that cash. Returns on small animals are maybe smaller, but they are more frequent, and this fits with the needs of the poor for small amounts of cash to handle an emergency (Todd 1998). 

A useful feeding strategy based on local resources has to go hand-in-hand with poverty alleviation for maximum socio-economic impact. The emphasis should be on small livestock such as chickens, ducks, pigs, goats, rabbits and within the principle of the "ladder concept" and according to the specific traditions and customs of a location. 

The specific strategy that is proposed is that there are there many alternatives to cereal grains as the basis of feeding systems for livestock production and that many of these systems result in a more efficient and sustainable use of natural renewable resources. The first step in this strategy is to recognize that the production of cereal grains for livestock feed, as practised in the industrial countries, is not sustainable because it depends on the inputs of massive amounts of energy derived almost exclusively from fossil fuel. According to the data from Pretty (1995), the production of rice in the USA requires that some 65% of the energy value of the rice is imported into the system in the form of fossil fuel derived inputs. The energy need for maize is less (about 25%) but still substantial. 

The examples of alternative energy-rich crops proposed by Preston (1995) include sugar cane, cassava roots, sugar palm, oil palm and coconut palm. The yields of all these crops expressed in terms of grain equivalent exceed what can be expected from cereal grains. Moreover, many of them, for example the sugar palm tree, can be grown in association with other crops in multi-strata systems and are much less demanding in terms of energy inputs for cultivation. The limitations of all these alternative crops, as sources of feed for livestock, are in the imbalance of nutrients and specifically protein. On the other hand, they are all low in fibre. In fact, the energy from sugar cane, and the palm trees (oil and sugars) contains no fibre at all. 
 

The feeding systems designed so far, using these new resources, have relied mainly on conventional sources of protein such as meals from soya bean, groundnut and fish (Sarria et al 1990; Ocampo 1994; Khieu Borin and Preston 1995). This is obviously a major constraint as these conventional protein-rich meals are relatively low yielding and soya bean, which is the major protein crop, is not well adapted for growing in the tropics where they yield much less than when grown in sub-tropical regions. 

Ngyen thi Loc et al (1997) showed a clear example in a village study in Vietnam where the availability and price of conventional protein supplements are major constraints to pig production. A survey in two villages in Central Vietnam revealed that protein intake was very low in traditional diets (94 - 98 g/pig/day). A feeding trial was carried out in the same two villages to test effects of providing supplementary protein to the traditional diet. Fourteen weaner pigs (Mong Cai x Large White) were fed traditionally, and another 12 pigs on similar basal diets were given supplements of groundnut cake and fish meal to provide an additional 100 g/day/pig of crude protein. The mean daily live weight gain of pigs under the traditional feeding system was low (202 and 230 g/day in each of the two villages) but was significantly increased to 363 and 366 g/day (P=0.001) by giving the protein supplement. The net economic benefit after deducting the cost of the protein supplement was VND 900/day (USD0.08) equivalent to VND 135,000 (USD11.30) for the 150 day fattening cycle. 

It is clear that the challenge is to use alternative sources of protein which can be produced efficiently on the farm (Preston 1995). These include the leaves of many trees and shrubs and several water plants as examples of truly tropical feed resources capable of very much higher protein yields than soya bean (Figure 2). The major nutritional limitation of these feed resources is that they are relatively high in fibre, especially the leaves and foliage from trees and shrubs, which puts a constraint on their digestibility, especially by monogastric animal species. Thus the characteristics of these alternative sources of energy and protein, when combined into feeding systems, can be summarized as follows: 

• High productivity and efficiency in use of natural resources (eg: land, water and solar energy). 
• Relatively low inputs needed for cultivation. 
• Low nutrient density and low digestibility in the case of tree leaves. 
• Limited shelf life in the fresh state (eg: juice from sugar cane and sugar palm).

Production systems from locally available resources

• The feeds are not suitable for incorporation into the conventional "balanced rations" in a feed mill, as is done with cereal grains and protein meals
• For maximum economy, the livestock must be located close to the source of the feed as the high volume and short shelf life of the fresh product makes transport expensive
• The feeds are less suitable (compared with a conventional maize-soya mixture) for livestock of high genetic potential in view of the relatively low nutrient density and constraints in protein supply 
• More of the original feed will be excreted in the faeces than in the case of cereal-protein meal feeds, because of the lower digestibility (which may be an advantage when manure is an essential component of the production system) 
• Genotype-environment interactions will be accentuated 

It is evident from this analysis that the feeding and farming systems that need to be developed in order to take advantage of the opportunities offered by these alternative feed resources will be quite different from those currently practised in most industrial countries. This in turn has implications for research, training and acquisition and transfer of knowledge. Appropriate knowledge will rarely be found in the scientific publications emanating from institutions in the "North". Farmers in the "South" who over generations have learned how to use the locally available resources will be more valuable sources of information. 

Similarly, appropriate germ plasm is more likely to be found in local ecosystems than in the laboratories and experiment stations of the animal and plant breeders in the industrial countries. There are many examples of situations where indigenous breeds and local feed resources have proved to be more appropriate than exotic types and imported technologies. Crossbred (F1) Holstein-Zebu cattle were more efficient producers of milk and meat in a tropical environment in Brazil (Madalena 1989) and in Colombia (Rodriguez and Cuellar 1994) than the purebred Holstein. Leaves from the Jackfruit tree (Artocarpus heterophyllus) supported higher live weight gains in indigenous goats in Vietnam than the more digestible foliage from Trichanthera gigantea (Keir et al 1997). Hybrid broiler chickens quickly succumbed to disease and malnutrition when they were put in an environment where "scavenging" local chickens were able to produce normally (Hong Samnang 1997, unpublished data). The Mong Cai pig of Vietnam (Picture 1) appears to have comparative advantages over imported "exotic" strains when the need is to be able to consume large quantities of a voluminous feed such as duckweed (Rodriguez and Preston 1996) 

Alternative protein sources

Duckweed can be grown in an integrated system with livestock and low-cost plastic biodigesters. Biodigesters are an efficient way to use the manure from livestock as it is possible to get gas for cooking and may be the most important is the use of the effluent to fertilize the crops, or duckweed as a source of low cost but high quality protein. Duckweed can be a good supplement for scavenging chickens (Hong Samnang 1998, unpublished data) and ducks (Bui Xuan Men et al 1996). 

The cassava tree grown in an integrated farming system, and heavily fertilised with organic manure, can produce up to 0.9 kg of leaves/m² at 45 to 60 day harvest intervals. This amounts to an annual yield of up to 60 tonnes leaves /ha (Preston et al 1998). The dry matter content is around 25% and the protein content of the dry matter is 25% (Nguyen Van Lai and Rodriguez 1998). 

Cassava is grown almost everywhere in the tropics and when managed as part of an integrated farming system becomes an important source of high quality protein at farm level. 

Cassava leaf has a high content of HCN which can be toxic for monogastric animals but there are ways to reduce this to a safe level. The most common way is to dry the cassava leaves but the most suitable is to ensile the leaves anaerobically with 5% of molasses. The procedure to do it is very simple and easy to adopt and adapt by the farmers (Nguyen Van Lai et al 1998). 

In Figure 5 is shown the potential to produce protein in an integrated livestock-biodigester-duckweed-cassava system. In an area of just 108 m² it is possible to produce enough protein to satisfy the needs of 4 Mong Cai sows. 

Picture 2 shows the model in the UTA campus in Vietnam. Duckweed is harvested every day and fed to the pigs and chickens and cassava leaves are harvested each 45-50 days, ensiled with 5% of molasses and after 6 weeks it is fed to the pigs (Picture 3). 

These are not prescriptions, but options to be placed in the "basket of choices" (Chambers and Ghildyal, 1985) which farmers can choose from. 

Pig production from Sugar Palm in Cambodia

In the study cited above, the fresh juice was fed to crossbred (Yorkshire x Duroc x Haiman) pigs in 14 farm households in a village in the Takeo province of Cambodia. Each farmer had 6 pigs and access to at least 12 sugar palm trees; housing was constructed from palm trunks with roofs thatched with palm leaves and solid concrete floors. Each farm had a plastic biogas digester installed to utilize the effluent. The pig diet consisted of ad libitum sugar palm juice, together with 400 g/day boiled whole soya bean seed with added lime and salt and 500 g/day water spinach. Live weight gains ranged from 350-450 g/day. More importantly, the system was more profitable than sugar production which needs firewood for concentrating the juice. The system was less labour-intensive and the pigs produced manure which was transformed through biodigesters to effluent and used as fertilizer for fish ponds, water plants or rice and fruit trees, with no harmful effects on the environment. 

Alternatives of energy 

Many developing countries, such as Colombia, Ethiopia, Tanzania, Vietnam, Cambodia, promoted the low-cost biodigester technology aiming at reducing the production cost by using local materials and simplifying its installation and operation (Solarte 1995; Chater 1986; Hieu et al 1994; Sarwatt 1995; Soeurn 1994; Khan 1996). To this end it was decided to use a continuous-flow flexible tube biodigester based on the bag digester model as described by Pound et al (1981) and later simplified by Preston and co-workers first in Ethiopia (Preston T R, unpublished data), Colombia (Botero and Preston 1987) and later in Vietnam (Bui Xuan An et al 1995). Up to September 1998, more than 7,000 polyethylene digesters have been installed in Vietnam, mainly paid for by farmers (Nguyen Duong Khang, personal communication). 

The low cost plastic biodigester can be used in different scales according to the farm situation. For the small scale farmer in remote areas where fuel is not easily available the biogas plays an important role as a source of fuel specially for cooking. In other areas where fuel is available the potential of the digester is the use of the effluent for fertilization of crops such as cassava, forage trees and as a source of nitrogen for aquatic plants such as duckweed (Lemna minor). All these crops (including the leaves of the cassava) can provide protein for the livestock in the farming system (Picture 5 y 6). 

For medium and large scale farmers, biogas can be used to replace part of the oil to produce electricity and the effluent can be used to fertilize the crops. In picture 7 are shown two biodigesters made of plastic and each one of capacity of 75 m3 and the gas is being used to heat the piglets in a unit of 100 sows. In this farm there are more digesters and the gas is also used to replace fuel in a diesel engine to generate electricity (Cuellar and Madriñan 1997, Personnal communication). 

Light is also a human need and in this aspect solar panels also can play an important role in remote rural areas. Two panels each of 12W capacity connected to a car accumulator will generate sufficient energy to provide light for 3 to 4 hours daily (Preston T R , unpublished data). But to be able to transfer this technology on a large scale the panels need to be cheaper as many rural families can not afford them. 

Optimizing the total system

Manure is an important source of fuel in many Asian cultures. It is estimated that 8 to 12% of the world's population depend on manure for heating and cooking (Ramachandra 1994). Animal manure is a valuable fertilizer as well, conferring inputs to the soil over and above the simple chemical nutrients of N, P and K. As an input into the crop cultivation systems, manure continues to be the link between crop and animal production throughout the developing world. 

The great challenge is to develop better ways of increasing the benefits to society and to the environment that manure can bring (Beteta 1996). One way to improve a better utilization of manure is undoubtedly through biogas production and cultivation of earthworms (Figure 6). 

Biogas is considered one of the cheapest renewable energies in rural areas of developing countries. Production of biogas would not only save firewood but also be beneficial for integrated farming systems by converting manure into an improved fertilizer for crops or in ponds for fish and water plants. Other benefits of biodigestion include the reduction of manure smell, elimination of smoke when cooking and the destruction of pathogens and thereby improving the environment in the farm (Bui Xuan An et al 1996). 

When livestock are available, and there are suitable conditions, a simple and low-cost biodigester technology can be developed. Earthworms provide another route for the recycling of manure and are especially appropriate for the processing of excreta from goats and rabbits which, for physical reasons, is not suitable as a substrate for biodigesters (Rodriguez et al 1995). 

The results reported here demonstrate that the basic model has many variants but the principles are the same. It is important to identify local feed resources and the preferences of local people for different types of livestock. In all cases, there should be minimum "waste" in the system. By-products and residues originating in one component of the system become inputs for another "productive" activity. 

Many small scale farms do not have all the components of the system. In these cases exchanges between households can take place via the market or village institutions. Alternatively, enterprises can be established which for instance collect waste for a fee from households, grow duckweed and sell to other households. In Vietnam some farmers grow duckweed and then go to the market to sell it to other farmers that use it as a livestock feed, principally for ducks (Nguyen Van Lai, unpublished data). 

The beneficiaries

What is the role of research in the development process? 

On-station or on-farm?

Methodologically, normal agricultural science is reductionist, excelling in exploring the relationships of a restricted number of variables in controlled conditions. This suits large-scale simplified farming in which the natural environment is highly controlled, with mono-cropping and standardised mechanical, fertiliser and pesticide treatments. For these reasons, much of agricultural science serves the needs and capacities of the rich and less poor (Chambers and Jiggins 1986) 

Normal agricultural research has a bad record with resource poor farmers. Part of the failure of agricultural extension with resource poor farmers stems from the lack of messages which fit their objectives and conditions.(Chambers and Jiggins 1986) 

On-farm research has many advantages. Farmers have always experimented to produce locally-adapted technologies, practices, crops and livestock (Chambers et al 1989; Brouwers 1993; Scoones and Thompson 1994). They are continuous adaptors of technology and their systems are rarely static from year to year. Richards (1989, 1992) has linked this process of adaptation to a performance, in which the actors change the nature of the performance according to the specific conditions. The problem is that researchers commonly do not understand or even accept that farmers can be "researchers". They assume that farmers are conservative and bound by tradition. Static and unchanging practices can therefore, upon investigation at a particular time, be characterized, analysed and so developed. But such an analysis can give nothing better than a snapshot of a complex and changing reality. It is important therefore, to begin to see technologies in a different light, not as fixed prescriptions but as indicators of what can be achieved. What agriculture needs is a willingness among professionals to learn from farmers. 
 

The "Farmer first and last model" (FFL) is an alternative to the "transfer-of- technology" model (TOT), and is based in the farmer's perceptions and priorities rather than on the scientist's professional preferences, criteria and priorities. The starting point is the scientific learning from and understanding of the resources, needs and problems of the resource-poor farmers and that the research stations and laboratories play a referral and consultancy role. This model is characterized by the use of informal survey methods, research and development within the farms, and with the farmers, and evaluation through the technology adoption (Chambers and Ghildyal 1985). 

Compared to a conventional experiment station approach, the research approaches discussed above are more comprehensive and they may make demands on skills beyond the capacity of the individual scientist and call for a team of scientists, representing different disciplines (Dolberg 1990). 

It is mentioned that education also plays a pivotal role in the whole process, but it will not be discussed further as the topic is so comprehensive as to require a separate paper. 

Conclusion

The strategy to develop feeding systems based on the use of local resources has to go together with the socio-economical aspects. The emphasis should be on small livestock such as chickens, ducks, pigs, goats in accordance with the "ladder concept", but should respect differences in countries and cultures. 

Research priorities have to be established to meet the necessities and the reality of the small scale farmers. 

The role played by livestock in farming systems for poor farmers is multi-faceted and synergistic and must be seen not as a primary form of production but rather in terms of their overall contribution to the total farming system and to the immediate needs of the family. 

Local breeds are better adapted to local environments and local resources and may out-perform the "improved" breeds under these circumstances. But more research is needed to identify their real merits in the context of integrated farming systems. 

On-farm research is an active process. Farmers have always experimented to produce locally-adapted technologies. Farmers are often excellent "researchers" and "extensionists". In this way, research and extension go together which is the best way. When the research is done on-farm, the process is faster and there is a "natural selection" of technologies and priorities. Therefore, there is less waste of time and money. In some aspects, especially when new technologies are being developed or adapted, it is advantageous if on-farm research is complemented with "on station" research. But there must be a clear understanding of, and link with, the reality of the farmer situation. 

Integrated farming systems offer unique opportunities for maintaining and extending biodiversity. The emphasis in such systems is on optimising resource utilization rather than maximization of individual elements in the system. 

The well being of poor farmers can be improved by bringing together the experiences and efforts of farmers, scientists, researchers, and students in different countries with similar eco-sociological circumstances. 

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