Assessment of the relationship between body surface temperature and behavioral responses in rams using infrared...

Animals under heat stress change their behavior to regulate their body temperature, as higher temperatures lead to a decrease in feed intake, thereby affecting production.

This study aimed to evaluate the relationship between the temperature of different body parts measured by a thermal camera as a non-invasive indicator and the behavioral responses shown by the animal under different environmental conditions to predict these responses and understand the physiological and emotional state of rams.

The temperature-humidity index (THI) was used to define the environmental conditions. Infrared thermography was used to measure body surface temperatures (forehead, eye, nose, ear, and back), while concurrent behavioral observations were recorded.

A higher THI was associated (p ≤ 0.01) with significant increases in fear, pushing, and panting behaviors (reaching 12.79, 7.59, and 66.48 events/hour, respectively) and a rise (p ≤ 0.05) in water consumption (4.41 times/hour). Conversely, lower THI was correlated (p ≤ 0.01) with increased feed consumption, huddling, resting, and active movement. The surface temperatures of the forehead, nose, ear, and back increased significantly (p ≤ 0.01) with higher THI (reaching 39.44°C, 38.45°C, 37.30°C, and 38.38°C), while the eye temperature also increased (p ≤ 0.05; 36.87°C). Thermographic measures of the forehead, eye, nose, ear, and back showed positive correlations with fear, isolation, pushing, and panting behaviors but negative correlations with aggressive behavior.

These findings indicate that body surface temperature, measured via thermal imaging, is sensitive to environmental stress and correlates with specific behavioral responses in rams. This supports the potential use of infrared thermography as a non-invasive tool for predicting behavioral changes and assessing welfare states.