Environmental impact on production

Weather and climate influence both farm animal production and agronomic production. There are many differences, some obvious and some subtle, in the way animals and plants respond directly and indirectly to given environments, however. It explores the applications of weather and climate information to sustain or improve on-farm animal performance, such as survival, growth, reproduction, and milk and wool production. Management intervention is needed not only to improve the genetic potential of the animals, but also to help overcome the constraints on production set by the climate, the physical environment and the health hazards in a region. On-farm decisions usually involve selection, design and management of production facilities, while the collective impacts may guide regional or national policy, determine responses to potential large-scale changes, or influence other decisions. The case for understanding the implications of regional and local climates affecting those decisions is self-evident, as is the need for timely forecasts to trigger management anticipation and response to adverse conditions.

Background Animal production problems associated with weather and climate go beyond an understanding of the processes and variations in the atmospheric boundary layer and the role of local ground cover and topography in those variations. Knowledge of how potential environmental stressors (ambient temperature, humidity, thermal radiation, air speed) can directly and adversely affect animal performance, health and well-being when coping capabilities of the animals are exceeded is also required . The indirect consequences of weather episodes, such as their impact on feed quality and availability, must also be recognized. Factors for consideration in animal production include:

• Thermoneutral ranges of environmental variables for important classes of livestock in the light of weather and seasonal variations that can occur. Past weather data (both conventional and derived climate data) should be analysed and interpreted for the specific purpose of establishing risks and probabilities;
• Evaluation of detailed energy budgets for individual animals and groups of animals, which can indicate imbalances. Responses of animals to potential environmental stressors that can influence performance and health Intensity Duration Animal response Normal function Disrupted behaviour Impaired immune status Potential environmental stressor Animal Feedback Impaired physiology Behaviour Immunology Physiology Coping Reduced performance or health Impaired function Conditioning, adaptation, nutrition, life stage, genetics, etc.
• Development of an understanding, preferably quantitative, of how environmental variables affect the heat budget of animals. The heat budget, which is based on heat exchanges that depend on factors should suggest how the ambient environment might be manipulated by natural and man-made shelter against wind, sun and precipitation; by site selection to increase or decrease exposure; and by artificial aids that would directly provide additional heating or cooling;
• The possibility that animal housing offers improved animal and economic performance. A plan to change the external macroenvironment into an acceptable microenvironment also calls for an energy budget approach, with the house and its animals as the unit, and ventilation (natural or fan assisted) as the primary control variable;
• The weather dependency of disease and parasitism, especially the timing and scale of the problem; whether exposure to a new infection results in disease depends, among other factors, on the number of infectious organisms taken in and the occurrence of