Demographic, morphological and coat factors in dogs after exercise at a fast course ability test (FCAT) trial

Domestic dogs are a widely diverse species of endothermic mammals that show a positive correlation between body mass and whole-animal metabolic rate, but a negative correlation between body mass and lifespan, making them an interesting system for determining thermoregulatory patterns in relation to body mass, body morphology, and age within a single mammalian species. Though previous work has found differences in thermoregulation across seasons and with training in dogs of different sizes, we now seek to determine (1) whether sampling event-related temperature differences remained when dogs exercised intensely and acutely outdoors and (2) whether thermal differences were also expressed in short-term burst exercise in athletic dogs compared to long-term exercise in non-athletic dogs, as previously found. Here, we measured tympanic membrane temperature (T_ear) as a correlate of core or internal body temperature (T_b). We also measured changes in body temperature across different body surfaces using thermal imaging (T_eye, T_nose, and T_mouth) in dogs after exercise during Fast Course Agility Trial (FCAT) competitions between spring and summer months in Central New York State, USA (N = 20, July and August N = 26). We correlated these data to each dog's body mass (average(± standard error) = 29.97(± 0.24) lbs.), age (5.99(± 0.78) years), and various aspects of body part measurements and coat characteristics, such as length, type, and color. First, in our overall dataset, being sampled in May was the most significant predictor of temperature slope (p < 0.001), and we identified far more significant predictor variables in the May event dataset than in other datasets. Second, as we gave special attention to our study population, we found that running an outdoor, burst exercise course (FCAT trial) shows a different pattern of thermoregulation compared with previous work. Thus, our data may offer preliminary insights that thermoregulation in dogs varies with sampling event and exercise type, though additional research is needed to understand the complexity of these observed patterns. Our data also provides evidence that responses can be plastic depending on the dog's individual phenotype and that athleticism may affect thermoregulation in dogs, similar to humans.