Seasonal changes in the body surface temperature of Hanwoo (Bos taurus coreanae) steers

Abstract

The present study aimed to gather basic information on measuring body surface temperature (BST) of cattle by using infrared thermography (IRT) and find out whether BST measurement is a useful method to detect thermal balance of livestock. Twenty-seven Hanwoo steers were examined in a field trial. The BST of five body regions (eye, nose, horn, ear, rear) was measured five times daily, with three replicates, during 3 days each season. Body surface temperature of cattle is directly affected by ambient temperature and humidity, and showed different ranges for each region. The BSTs of nose, horns and ears were significantly (P < 0.05) lower than those of eyes and rear area. Rear-area BST was significantly lower than eye-area BST when the ambient temperature was low (P < 0.05). Eye BST (EBST) was highest (P < 0.05) and the least variable of all BSTs measured. Therefore, the eye area of cattle was the most thermostable part of the body. There were significant (P < 0.05) differences among seasonal EBSTs of steers. The EBST range was highest in the summer (37.9-42.2 degrees C), followed by autumn (34.3-37.4 degrees C), spring (33.8-36.5 degrees C) and winter (29.8-32.6 degrees C). During extreme cold, EBST showed a large standard deviation. During conditions of extreme heat, EBST was above the average body temperature of cattle. The results of the present study indicated that BST well reflects the thermal circumstances surrounding animals and may be used as one of the effective tools for precision cattle farming.