Livestock play a very important role in the agriculture of most developing countries, accounting on average for an estimated half of agricultural output through their direct and indirect contributions. Major functions include: production of human-edible food from human-inedible forages, crop residues and by-products; concentrating nutrients, thus increasing the quality of food and producing high-value products for sale; serving as a source of savings and income for producers who lack access to banks or credit; recycling plant nutrients and improving soil fertility; serving as a food reserve; and providing draft power. Crop-livestock systems are in general more stable and more productive than cropping systems alone. A perceived problem due to livestock is overgrazing and environmental degradation, but these are usually the result of human mismanagement of the animals. Traditional pastoral systems can be not only persistent, but ecologically sound. The currently observed problems associated with pastoral systems in arid and semi-arid lands are more likely to result from breakdown of traditional management practices due to human population increase and external intervention or social changes, or from abiotic factors such as climatic variation, than from flaws in the traditional system. Research and development programs can increase the contributions of animals to the well-being of their owners and to the economies of developing countries. Some areas with high potential include: evaluation of local genetic resources; assessment of feed resources and design of economical, efficient supplementation strategies; and reduction of costs of disease control by development of multivalent vaccines. There are opportunities for large increases in efficiency of resource utilization and animal productivity. However, a more thorough understanding of social and economic as well as biological aspects of production systems than has usually existed in development projects is essential for interventions, where they are indicated, to be effective. Key words: Food quality, efficiency, production systems, sustainability, genetic resources, animal traction
Efectos de la capacidad innovadora en el crecimiento económico. Análisis comparativo entre países desarrollados y en desarrollo