Effects of short-term changes in ambient air temperature or altered insulation in horses

Abstract

1. 1. The main aim of this experiment was to study the physiological responses in standing horses exposed to an acute short-term change in ambient temperature. A second aim was to study the effect of changes of coat insulation on the physiological responses of the horse. 2. 2. The parameters studied were body core temperature, heart rate and respiration rate. 3. 3. The measurements were performed on five horses exposed to six different temperatures between −3 and 37°C in a climatic chamber. The measurement of the effect of changes in coat insulation were made in 6°C and the treatements were shearing and covering with a rug. 4. 4. No effects on heart rate or in body core temperature were found in the main study. The respiration rate increased in ambient air temperatures above 20°C. 5. 5. In the measurement of the effects of insulation, the sheared horses had a lower mean respiration rate compared to the horses with intact coat. All horses, except one of the sheared horses, maintain normal body temperature. There was no effect on heart rate.