TEMPERATURE HUMIDITY INDEX FOR GROWING TOM TURKEYS

Temperature-humidity effects on physiological responses of tom turkeys were investigated using a two-dimensional rotatable central composite design. Eight temperature-humidity combinations were evaluated from 2 3 to 40 degrees C and 40 to 90% RH. Response surfaces for mean, variat ion, and slope of core body temperature, CO2 production, and moisture production were used to assess level of stress at each of four ages. T emperature and humidity were approximately equal in their effects an p hysiological responses of 6-wk-old tur-keys. Above 10 weeks of age, te mperature decreased in relative significance as a stressor, and humidi ty appeared to be a more important factor in the birds' ability to mai ntain homeothermy.