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Andrew Speedy
Senior Officer (Feed and Animal Nutrition)
Animal Production Service
FAO Animal Production and Health Division

Biomasse, élevage, population et environnement

Il y aura 10 milliards de personnes dans le monde d'ici l'an 2025, mais la production agricole a un potentiel de développement limité. Or, nous utilisons actuellement pour l'alimentation humaine moins de 1 pour cent de la biomasse totale produite par photosynthèse (production primaire nette). A travers l'élevage, des ressources impropres à la consommation humaine sont transformées en protéines et en énergie pour la table familiale. Des ressources végétales comme la canne à sucre, les palmiers, les arbres fourragers et les plantes aquatiques devancent largement, en termes de production de biomasse, le maïs et d'autres produits d'alimentation animale traditionnels. L'utilisation des ressources locales pour l'alimentation des animaux, dans le cadre de systèmes intégrés de production familiale, suscite un intérêt croissant. Les entraves au développement des petites exploitations familiales se situent le plus souvent au niveau des moyens financiers nécessaires pour l'achat des équipements et des ressources de base, du soutien institutionnel et de l'infrastructure nécessaire pour la commercialisation à petite échelle des produits. L'enjeu est donc d'améliorer les communications à la base. Le développement au niveau local a des effets positifs à l'échelle planétaire.

Biomasa, ganado, población y medio ambiente

Para el año 2025 habrá en el mundo una población de 10 000 millones de habitantes, pero el potencial para aumentar la producción de los cultivos es limitado. Sin embargo, en la actualidad utilizamos menos del 1 por ciento de la biomasa total que se produce por fotosíntesis (producción primaria neta) para la alimentación humana. El ganado transforma en proteínas y energía destinadas al consumo familiar recursos de piensos que no son idóneos para el consumo humano. Hay recursos vegetales, como la caña de azúcar, las palmas, los árboles forrajeros y las plantas acuáticas, que superan con creces la producción de biomasa del maíz y otros piensos tradicionales. Cada vez es mayor el interés por la utilización de recursos de piensos locales en sistemas integrados de pequeñas explotaciones. Las limitaciones para el mejoramiento de la pequeña explotación familiar se deben a menudo a la reducida cantidad de capital que se necesita para el equipo de recursos básicos, el apoyo institucional y la infraestructura a fin de facilitar la comercialización en pequeña escala de los productos. El reto está en mejorar las comunicaciones en la base. El desarrollo a nivel local produce beneficios mundiales.

Biomass, livestock, people and the environment

We are repeatedly reminded by the Malthusian pessimists that there will be 10 billion people in the world in the year 2025, with most of the increase taking place in the poorer countries. Extrapolation of current grain supplies and the present limited potential for increasing wheat, maize and rice production suggest that the number of hungry people will increase and chaos will prevail in a hungry and over-populated world.

Yet we currently use less than 1 percent of total biomass produced by photosynthesis (net primary production) as human food, since much of this biomass is grass, straw, tree leaves, water plants and other indigenous flora which are unpalatable to humans. Livestock convert feed resources that are not suitable for human consumption into protein and energy for the family table.

Livestock do not only produce meat. They also provide power for cultivation and transport, and manure for fertilizer and fuel; they represent the capital wealth of numerous small farmers and are the main source of income in many rural economies.
Livestock development projects have had a poor record in the past. Many failures have occurred as a result of the inappropriate placement of breeds and the transfer of unsustainable technologies from North to South (intensive production systems based on maize and soybean, for example) - failures owing to the narrow focus of education and training on "animal science" prescribed by institutions in the North. Even such expressions as "genetic improvement" and "feed requirements" were misnomers since they actually referred to inappropriate use of resources and the development of livestock systems at a high cost in economic, ecological and social terms.
Fortunately, there has been a significant movement towards the more sustainable utilization of available resources, especially in the tropics and subtropics. There is an increasing body of knowledge based around the development of integrated systems of livestock, fish, crops and trees, much of which is emanating from the South. Some of these systems have been used for centuries by small farmers and are highly appropriate for the small family farm. Far from being the "poor cousins" of "modern" intensive systems, these multistrata, integrated systems produce more food of greater variety and quality. The small farmer is the key to increased food security, sustainability and long-term prospects for social stability.
Maize, even under good conditions, produces a few tonnes of dry matter per hectare, less than one tonne of which is protein. (In dry areas, it is likely to produce much less and crop failures are frequent.) Sugar cane can produce several hundred tonnes of biomass per hectare and can be used for pigs (the juice) and for ruminants (the pressed cane stalk). Similarly, palm trees can be the basis of high-production systems (apart from the grazing under the trees) and this includes not only the well-known oil-palm (whose fruit or by-products can be used as feed) but also such lesser known species as the sugar palm (see the article by Khieu Borin). The legume trees not only produce high biomass yields but also fix nitrogen and can satisfy the protein demands of ruminant livestock. Mulberry trees are reported to produce 15 tonnes of dry matter per hectare, providing sustenance and allowing excellent performance of cattle, goats and sheep (as well as silk worms). Cassava, grown as a shrub and given high levels of organic manure, can produce more than 10 tonnes of dry matter per hectare per year, including 3 tonnes of protein. Water plants such as Lemna and Azolla species can provide a green feed factory in the small farmer's pond.
All these are known to small farmers in the tropics but have been disregarded by the livestock "improvers". There is now increasing interest in using local feed resources within integrated small farming systems which produce grains, tubers, fruit, vegetables, meat and milk, with manure for fertilizer and for the production of fuel as biogas. The systems are self-contained, sustainable and diverse, providing food for the family and for sale, and insuring against failures of particular crops and markets. They employ family labour, the major contribution being made by women and children.
The limitations on development for the small family farm are often the lack of the small amount of capital necessary for basic equipment, the availability of stock and planting material (tree nurseries, for example), the institutional support for their activities and the infrastructure to assist the small-scale marketing of produce, especially such perishables as milk. Great strides could be made in local development in many places by providing a few "nuts and bolts", rather than completely new "machinery". The provision of basic veterinary services at the local level by village trainees is a good example (see the article by Mehraban, Ward and Otte).
In this issue, the article by Rushton and Ngongi on rural poultry highlights the need for consideration of cultural and market constraints as well as technical interventions. Better access to extension services is called for, especially for women producers.
There have been some successful examples of small farm development and some demonstrations of highly productive integrated systems. While global communications develop at a rapid pace, there is a need to spread information at the village level, to collect and pass on the good ideas with the greatest potential for the small farmer.
The Big Project is inappropriate. Focusing on one species or one aspect of production and "selling" the results in order to claim success are not what is needed. This is especially true when the focus is on cattle, maize and commercial crops which are of no interest to the small farmer. Rather it is better to collect and disseminate appropriate small-scale technologies and make them available to the farmer. A range of choices allows the individual to select the most appropriate system for the local environment. As with "biodiversity", diversity in farming systems is good for the environment and for supplying the market with a range of produce in response to demand.
Many good ideas have been presented in the pages of World Animal Review. The challenge is to improve communications at the grassroots level so that more farmers get to hear about them. Development at the local level has global benefits. Highly productive small farms can supply the food needs of the world, with benefits to the environment and society. It is time for global action at the level of the individual.
The Editorial Advisory Committee would like to record its sincere thanks to Brian Hursey who, at the end of January 1999, will be handing over the editorship of World Animal Review to Andrew Speedy.
Le Comité éditorial adresse ses très sincères remerciements à Brian Hursey pour sa contribution à la rédaction de la Revue mondiale de zootechnie. Son mandat se terminant en janvier 1999, Andrew Speedy lui succédera.

El Comité Editorial presenta sus más sinceros agradecimientos a Brian Hursey por su apoyo profesional en las actividades de programación y supervisión de la Revista mundial de zootecnia. Brian Hursey finalizará su mandato en enero de 1999 y será reemplazado por Andrew Speedy.

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