The scope is enormous and so is the task. The association between humankind and animals dates back to prehistoric times but, although the environment may previously have been hostile it is only in recent times that it has become necessary to consider how to satisfy human needs for food without destroying the environment in which that food production must take place. The domestication of animals and their integration with crop agriculture have provided the main avenue for agricultural intensification and this, in turn, has allowed for unprecedented economic and human population growth. Livestock production, mainly as a result of pressures in this process, has become an important factor in environmental degradation. Large land areas have become degraded through overgrazing and deforestation because of ranching.
Biodiversity is affected by extensive as well as intensive livestock production.
Water availability in low-rainfall areas is affected by livestock. Where animal concentrations are high land and water may be polluted through waste from animal production and processing. All these pressures on the environment are the result of a process of change in which the rising demand for livestock commodities is creating a new role not only for livestock but also for the environment. In essence, the conflict between livestock and the environment is a conflict between different human needs and expectations. Table 1.1 Animal production growth rates in percent for major livestock products from 1990 to 1995.