Sustainable systems of intensive livestock production for the humid tropics using local resources

Abstract

AbstractThe design of sustainable intensive livestock production systems for developing countries must be judged according to their likely impact on economic, ecological, ethological and sociological issues. Economic issues to be satisfied include international competitivity in price of finished products which requires maximizing comparative advantages of available natural resources. Ecological sustainability requires that the production system will result in (i) reduced emissions of the principal greenhouse gases carbon dioxide and methane; (ii) reduced contamination of soil and water resources; (iii) an effective control of soil erosion; and (iv) self sufficiency in on-farm production of energy from renewable resources. Ethological concerns relate to potential effects of production systems on animal welfare and the safety and consumer acceptability (wholesomeness) of foods produced in such systems. Sociological acceptability requires that employment opportunities are increased, especially for women, and that the production system encourages self-reliance with minimum dependence on outside inputs.The basic technology, designed and adapted by Convenio Interinstitucional para la Producción Pecuaria en el Valle del Rio Cauca (CIPAV) and cooperating local farmers in the Cauca Valley of Colombia, uses sugar cane, multipurpose trees and water plants as sources of biomass to provide food for a range of livestock species and fuel for the farm and the family. The chosen crops have a proven high capacity to fix atmospheric carbon dioxide and nitrogen into biomass, which is a permanent carbon reservoir (1 ha planted in sugar cane and trees is a sink for some 80 t carbon dioxide), and also a source of substrate for food and fuel. Sugar cane and trees help prevent erosion, maintain soil fertility, have well developed systems of biological pest control, require minimum synthetic chemical inputs and are easily separated into high and low fibre fractions as required for the different end uses of food for monogastric and ruminant animals and fuel.The preferred animal species are pigs and ducks which adapt readily to the ‘non-conventional’ high-moisture food resources (mainly cane juice, tree leaves and water plants) and have a high meat : methane production ratio. They are complemented by African sheep, dual purpose (Holsteinzebu) cattle and buffaloes, managed as triple purpose animals (draught, milk and meat) and deriving most of their food from the more nutritive parts of the fibrous crop residues. All the livestock are managed in partial or total confinement to minimize environmental damage and to maximize nutrient recycling to the crops.Fuel for the family is derived from the biodigestor which uses as substrate the excreta from the pigs; and from the sugar cane bagasse. Earthworms upgrade the fertilizer value of the excreta from the ruminant animals and produce part of the protein for the ducks.The CIPAV model is flexible as witnessed by the increasing acceptance of many of the elements in the model by both resource-poor and entrepreneurial farmers. The biomass concept, on which the CIPAV model is based, can also be scaled up to the level of agro-industry (the biomass refinery) offering renewable alternatives to present fossil-fuel-based technologies for chemical and energy needs.