Tympanic Temperature Profiles of Confined Beef Cattle

Angus crossbred yearling steers were used to evaluate tympanic temperature (TT) profile of cattle displaying high, moderate, or low levels of heat stress. Data indicate cattle that do not adequately cool down at night are prone to greater body temperatures during a subsequent hot day. Cattle that are prone to displaying moderate levels of heat stress but can cool at night will maintain average tympanic temperatures at or near those of cattle that tend to consistently maintain lower peak tympanic temperatures. In addition, during cooler and moderately hot periods, cattle change TT in a stair-step or incremental pattern, while under hot conditions, average TT of group-fed cattle moves in conjunction with ambient conditions, indicating that thermoregulatory mechanisms are at or near maximum physiological capacity