Estimating Thermal Comfort for Piglets Considering Ammonia Concentration

Swine production in tropical climate is mainly housed in open sided buildings predominantly with natural ventilation. Ammonia is produced from the animal’s excreta and it has particularly high concentration during the afternoon when the environmental temperature increases. The overall housing environment can be understood as the thermal environment associated to other sources of aerial agents such as ammonia, and when exceeding certain limit it may affect the swine’s performance. This research aimed to develop an algorithm to estimate the piglet limit to ammonia exposition associated to ambient temperature in the housing environment. Wet bulb temperature and black globe temperature index (WBGT) were registered continuously in a piggery in Southeastern Brazil from November 2002 to October 2003. A statistical analysis was applied to the registered input data for determining the significance of the obtained values in order to build a base of rules and generate input data related to the local weather and housing conditions. Fuzzy inference was made using Mamdani method in the software Matlab ® 6.0 Toolbox. A surface function of the thermal comfort values and the interaction between WBGT and ammonia concentration values wa