Tm. Brownbrandl et al., PHYSIOLOGICAL-RESPONSES OF TOM TURKEYS TO TEMPERATURE AND HUMIDITY CHANGE WITH AGE, Journal of thermal biology, 22(1), 1997, pp. 43-52
1. Using a 3-factor uniform-precision rotatable central composite desi
gn, male turkeys at 5 ages (5-20 weeks) subjected to 5 temperatures (T
, 25-40 degrees C) and 5 relative humidities (RH, 40-80%) during 2 h e
xposure periods were assessed for body temperature (BT), moisture prod
uction (MPM), CO2 production, respiration rate (RR) and heart rate (HR
). Prediction equations based on thermal conditions were developed for
each physiological response. 2. For the temperature range selected, R
H had a stronger effect than T. Maximum RR occurred at lower T and RR
was more variable in older, heavier birds. 3. Twenty-week-old birds us
ed compound ventilation in addition to panting, which may have reduced
the severity of heat stress and the consequent lack of a significant
change in body temperature. (C) 1997 Elsevier Science Ltd.