The effect of fleece on core and rumen temperature in sheep

Temperature loggers were implanted to record core body temperature (Tcore) and rumen temperature (Trumen) in sheep. The relationship between Tcore and Trumen was compared for fleeced and shorn Merino sheep over a range of environmental temperatures and during stressors involved with shearing. Fleeced sheep maintained higher Tcore and Trumen than shorn sheep in all environmental conditions tested (from thermoneutral up to 33 °C and 55% relative humidity). Shearing of the fleeced sheep resulted in those sheep having a lower Tcore when exposed to hot conditions, compared to the previously shorn sheep. Respiratory rates of fleeced sheep followed similar patterns and were higher than shorn sheep under all environmental conditions. After the fleeced sheep were shorn, their respiratory rates decreased to rates similar to the previously shorn sheep when under heat load, suggesting heat loss other than respiratory evaporative heat loss was augmented.