Thermoregulatory responses of Japanese Quail to various air temperatures and humidities

Abstract

Measurements of rectal temperature (Tre), feather surface temperature (Ts), heart rate (HR) and breathing rate (BR) of adult Japanese Quail were taken at combinations of four mean relative humidities (rh) and stable or rising air temperature (Ta). Tre increased about 1.7° and 2.5°C at a stable Ta of 40°C from a Ta of 25°C at low ( 80%) rh, respectively. Ts passively increased with Ta while remaining above Ta as high as 41°C. Panting and gular flutter rates were synchronous and approached rates of 800/min at high rh and stable Ta of 40°C. The steady-state panting rate was a direct curvilinear function of ambient water-vapor pressure (Pw). HR was depressed at successively higher, stable Ta's or with slowly increasing Ta. This thermal bradycardia may be related to the degree of discomfort or stress experienced by the animal.