For an animal to maintain homeothermy, the ambient environment and the animal must exchange heat at a rate that permits balancing the metabolic heat production and the energy gains/losses from radiation, convection, conduction and evaporation. Ruminant animals primarily adjust evaporative heat loss to maintain homeothermy during brief exposures to adverse weather, but will reduce feed intake to lower heat production during prolonged hot weather. Swine and poultry primarily adjust heat production to maintain homeothermy.
Quantitatively, the level of heat exchange by each heat transfer mode is dependent on the magnitude and direction of the gradient involved. In hot environments, energy exchanges by radiation are dominant, while convective energy exchanges tend to dominate in cold environments. To alter the microclimate of an animal effectively through housing or environmental modification, alteration of one or more of the following factors must be considered: temperature and/or emissivity of the surroundings; air temperature; air velocity; air vapour pressure; radiation or shade factors; and conductivity of surfaces that animals might contact. Success in improving production and efficiency in most climates is possible if a rational approach is followed.
All animals require shelter for protection and comfort. They can perform better under favourable environmental conditions. Housing of animals need initial capital to the extent the goat farmers can afford. The animals are to be protected from high and low temperature, strong sunlight, heavy rainfall, high humidity, frost, snowfall, strong winds, ecto-parasite and endo-parasites.
High humidity combined with high temperature causes more stress to animals in tropics. Rainfall in cold climate also causes stress in temperate zone. Strong winds further aggravate the conditions both in tropics and temperate climate. Improved animal housing is crucial among them.
The preferred orientation of a shade structure depends upon whether or not goats are confined to the structure. Alignment of the long-axis in an east-west direction achieves the maximum amount of shade in summers under the structure and is the preferred orientation for confined animals. On the other hand, where goats are free to move with the shadow of the structure a north-south orientation is better. The advantage of this orientation is that it allows sunlight to dry out as much as 35-50% of the area beneath the shade during both the morning and afternoon hours.
Natural air movement under a shade structure is affected by it's height and width, the slope of the roof, and the presence of, or size of, the ridge opening. Air movement may occur naturally as breezes through the open sides of structures or by the concept of thermal buoyancy in which air warmed by the presence of animals and radiation through the roof creates air flow toward the ridge opening.
- Shade structures of 30 feet or less require a minimum eave height of 9-11 feet. Structures wider than 40 feet should have eave heights of 16 feet with open slit.
- There should be at least 50 feet of clearance between adjacent buildings or other obstructions.
- Gable roofs should have at least a 4:12 slope (6:12 is acceptable but difficult to work on) and continuous open ridge. Ridge caps if desired should have a minimum of 1 foot of clearance between it and the roof peak.
- Ridge openings should be a minimum of 1 foot wide plus 2 inches for each 10 feet of structure width over 20 feet.
- Painting metal roofs white and adding insulation directly beneath the roofing will reflect and insulate from effects of solar radiation and will reduce thermal radiation on goats.