CHANGES IN HEART-RATE, PLASMA-CORTISOL AND HEMATOCRIT OF SHEEP DURING A SHEARING PROCEDURE

Nine Merino wethers were individually subjected to a series of eight handling treatments of increasing complexity, culminating in partial shearing. The treatments were control, separation from other sheep, isolation, human presence, blood sampling, up-ending, exposure to shearing noise, and wool removal. Heart rate was recorded before, during and for 60 min after each treatment. Shearing was the only treatment which elevated heart rate significantly above pre-treatment values. Blood samples were taken before and after isolation in human presence, exposure to shearing noise, and wool removal. Haematocrit and plasma cortisol both increased significantly after shearing, but not after isolation. The response to shearing noise alone was less pronounced than to the actual wool removal. It is concluded that wool removal is more stressful than any of the other manipulations involved in the conventional system of shearing. © 1990.