Amelioration of Thermal Stress using Modified Roof in Dairy Animals under Tropics: A Review

Roof is an integral part of housing systems, which protects animals from solar radiation and rain water. During summer months, heat stress affects animal production adversely. Housing design and shade material play an important role in the microclimate modification and reduction of radiant heat load inside the shed. The most commonly used roofing materials include asbestos sheets, thatch, clay tiles, reinforced cement concrete, galvanized iron sheets, plastic sheets etc., which possess some merits as well as drawbacks. Ideal roof material should have high reflectivity, low conductivity, low under-surface emissivity besides being light, strong, durable, waterproof, good looking, free from tendency to condense moisture inside and economical. Since, animal houses are permanent structure in large organized dairy farms which cannot be changed frequently. Thus, it is worth giving to modify existing roof rather changing the whole structure, which can be achieved by roof modifications such as thermal insulation, polythene shade cloth or Agro-net, mud plastering, thatched asbestos roof, green roofs, roof paints, evaporative roof cooling, solar panels, etc. Effectiveness of roof may further be improved by using techniques of adjustment of roof height, eave length and angle of eave in years to come. A holistic approach which includes animal nutrition as well as animal genetics in addition to shelter management would be more promising in amelioration of heat stress of dairy animals in tropics.