No dynamic effector responses to fast changes of core temperature at constant skin temperature

Area of Science:

• Physiology
• Thermoregulation
• Animal Science

Background:

• Understanding thermoregulatory mechanisms is crucial for animal welfare and productivity.
• Dynamic responses of heat production and evaporative heat loss to core temperature changes require further investigation.

Purpose of the Study:

• To investigate dynamic responses of heat production and respiratory evaporative heat loss to changing core temperature in conscious goats.
• To determine if the rate of core temperature change influences thermoregulatory effector responses at constant skin temperature.

Main Methods:

• Conscious goats were subjected to controlled changes in core body temperature using external heat exchangers.
• Skin temperature was maintained constant by immersing animals in a circulating water bath.
• Core temperature was altered at rates up to 0.9°C/min, with both step and ramp changes applied.

Main Results:

• Thermoregulatory effector responses (heat production, evaporative heat loss) showed positive derivatives following step changes in core temperature.
• No negative derivatives were observed during sustained core temperature displacements.
• Slopes of effector responses to core temperature changes decreased at higher rates of temperature change.

Conclusions:

• Neither heat production nor respiratory evaporative heat loss are influenced by the rate of core temperature change.
• At constant skin temperature, thermoregulatory effector responses are proportional to the deviation of core temperature from its set point.