Effect of thermal stress on physiological and blood parameters in merino sheep

Abstract

Fifteen sheep where placed in climatic chamber and exposed to a high temperature (30°C). Then, the air movement was induced in order to examine its soothing effect on heat stress. The physiological reactions like respiratory and heart rates, as well as the morphologic, biochemical parameters and cortisol levels in blood were examined. It was found that under heat stress conditions, the respiratory rate increased up to 96.43 breaths/min, heart rate up to 107.79 beats/min, and white blood cells count decreased to 9.12 k/μL. The increased level of potassium, chlorine, and calcium was also observed. The increased air movement resulted in thermal stress soothing. A decrease in respiratory rate, heart rate, and cortisol concentration was observed. The study demonstrated that heat stress leads to serious changes in physiological and blood parameters in sheep but this effect can be minimised by air movement.