Irenilza de Alencar Nääs
College of Agricultural Engineering, State University of Campinas, Campinas, SP, Brazil. irenilza@feagri.unicamp.br
ABSTRACT
Each animal species has an individual range of comfort temperature, known as the thermal neutral zone which is defined as the range of effective environmental temperature, where the production is near the ideal. It is limited by the lower and upper critical temperatures were the animal needs to decrease or increase the rate of heat output to maintain a constant body temperature. Pigs have little thermoregulation ability, and they are animals sensible to weather variation. When they are young they suffer when exposed to cold temperatures, and when adults they are heat stressed when the ambient temperatures are high. Their adaptation to hot environment is particularly difficult as the genetic evolution for meat animals generated a large animal with poor heat exchange mechanisms. This is the reason that pigs reared under tropical, and subtropical climate require housing adaptations in order to present good performance. Environmental, physiological and behavioral factors may influence in the overall aspects of animal comfort and well-being. The productive and reproductive performance of swine in all production stages is influenced by their management system, which involves rearing characteristics, nutrition, and the adopted hygiene in the production facilities. During the lactation period, sows increase their metabolism requiring cooler environment while nursing piglets need high temperatures in order to maintain thermal comfort. This constitutes a challenge to design ideal housing and acclimatization patterns. Pigs heat loss decreases in high temperature environments during the growing and finishing period. This leads to decline in performance, which requires proper cooling systems in order to reduce heat stress. This presentation describes the rearing aspects of swine production in tropical and subtropical climate, and proposes cooling systems to alleviate heat stress in pigs reared under high ambient temperature. |
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