Effect of heat stress on vital and hematobiochemical parameters of healthy dogs

Background and Aim: Heat stress is a major challenge for animals, impairing their welfare and performance. This study aimed to determine the effect of heat stress on the vital and hematobiochemical parameters of healthy dogs. Materials and Methods: The experimental subjects comprised 10 dogs, encompassing seven males and three non-pregnant females between 2 and 3 years of age. Ambient temperature (AT) and relative humidity (RH) were recorded 2 hourly during the day and the temperature humidity index was calculated. Vital parameters [i.e., rectal temperature (RT), respiratory rate, and heart rate (HR)] were assessed and blood was collected from each dog daily for hematobiochemical analysis. Results: The RT (38.5±0.2°C) of dogs exposed to high AT and high RH (HA/HR) conditions was significantly (p<0.05) higher than that of dogs exposed to HA and low RH (LR) conditions (37.2±0.11°C). Under HA/HR conditions, packed cell volume, hemoglobin concentrations, and white blood cell counts were significantly lower than those of the same dogs exposed to HA/LR conditions. Conversely, under HA/HR conditions, the lymphocyte, monocyte, eosinophil, alanine aminotransferase, aspartate aminotransferase, and cortisol values were significantly higher (p<0.05) than the values obtained in dogs exposed to HA/LR conditions. Meanwhile, the alkaline phosphatase, urea, and glucose levels were significantly lower (p<0.05) in dogs exposed to HA/HR conditions. Conclusion: The exposure of healthy dogs to HA/HR conditions induced heat stress, which may have an adverse effect on their immune status, thereby affecting their health and welfare.