REGIONAL VARIATION IN TEMPERATURE HUMIDITY INDEX FOR POULTRY HOUSING

A building thermal model was used to compute hourly values of temperat ure humidity index (THI) for a broiler house with and without an evapo rative misting system. Hourly summer time weather data for 238 U.S.A. locations covering 30 years were used to develop extreme occurrences o f THI. Results were incorporated into a Geographical information Syste m (GIS) database to create isolines of THI and percentage of hours exc eeding a heat stress threshold. Regional variations in misting as a su itable cooling technique are presented in terms of hours reduction in annual heat stress. The technique may be used for assisting in managem ent decisions regarding poultry facilities housing design and siting, and with appropriate THI may be extended to other livestock production .