Physiological Adaptations and Thermoregulatory Indicators of Heat Stress in Bovine Production Systems

Heat stress is a major challenge for cattle production systems because it negatively affects animal welfare, health, productivity, and reproductive performance. This communication reviews the main physiological adaptations and thermoregulatory indicators associated with heat stress in cattle and illustrates their practical application under tropical conditions. Environmental and physiological measurements were evaluated in fifty adult Bos indicus cows in Tabasco, Mexico. Ambient temperature was recorded using black globe and dry-bulb thermometers under different environmental conditions, while rectal temperature was used as an indicator of internal heat load. Black globe temperatures measured under direct solar radiation were significantly higher than those recorded under shaded conditions (p < 0.05), particularly between 10:00 and 14:00 h. Rectal temperature increased from 38.73 ± 0.73 °C during the morning to 41.24 ± 2.00 °C during periods of maximum environmental heat load (p = 0.001). These findings demonstrate the close relationship between environmental heat load and thermoregulatory responses in cattle. Monitoring indicators such as black globe temperature and rectal temperature may provide practical tools for the early detection of heat stress and support management strategies aimed at improving animal welfare and production efficiency under tropical conditions.