Thermal relations in sled dogs before and after exercise.

Area of Science:

• Physiology
• Animal Science
• Exercise Physiology

Background:

• Thermoregulation is vital for endothermic animals, especially athletes who generate more heat.
• Canine athletes, particularly sled dogs with high VO2 max, require efficient heat dissipation mechanisms.
• Existing literature suggests canine athletes may have lower body temperatures than non-athletic dogs, indicating specific adaptations.

Purpose of the Study:

• To investigate correlations between ear temperature (T_ear) and body mass, morphology, and age in canine athletes.
• To analyze body-wide heat dissipation patterns using thermal imaging in sled dogs.
• To examine relationships between thermal variations in the mouth (T_mouth), nose (T_nose), eyes (T_eye), and head morphology.

Main Methods:

• Core body temperature (T_b) was measured using an instant ear thermometer before and after a 2-mile run.
• Thermal imaging was employed to capture heat dissipation patterns across the body.
• Measurements focused on T_ear, T_mouth, T_nose, and T_eye, alongside head morphology and body mass.

Main Results:

• T_ear was consistently the highest temperature, increasing by 1.5°C post-exercise (p < 0.001).
• Significant positive correlation found between T_mouth and body mass post-exercise (p = 0.0023).
• Negative correlations observed between T_nose and body mass pre-exercise (p = 0.0468), T_eye and nose length post-run (p = 0.0076), and T_mouth and nose length post-run (p = 0.0110).

Conclusions:

• Canine athletes possess distinct thermoregulatory strategies involving ear temperature and facial vascularization.
• Snout morphology plays a significant role in evaporative cooling and heat dissipation, particularly in highly athletic dogs.
• Understanding these adaptations is crucial for managing canine athletic performance and health.