CARDIOVASCULAR PARAMETERS IN SHORN SHEEP PRIOR TO AND DURING THEIR EXPOSURE TO A COLD, WET ENVIRONMENT

When shorn sheep were exposed to ambient temperatures of 3°C and the residual fleece was wetted, heart rate and cardiac output increased substantially above levels measured during a control period at 25°C. With continued cold exposure and wetting the sheep become hypothermic and heart rate and cardiac output decreased. In most sheep at rectal temperature 〈32°C cardiac output had fallen below control values while heart rate remained above control. In a minority of hypothermic sheep cardiac output remained above control rates.