Estimation of a reference interval for eye temperature in dogs

Objective: To estimate a reference interval (RI) for eye temperature (ET) in apparently healthy shelter dogs and to provide a comparative RI for rectal temperature (RT). Methods: This cross-sectional study was conducted at a municipal shelter over a 2-month period. We included apparently healthy dogs and excluded those with illness history, respiratory symptoms, or ocular discharge. Using a handheld thermal camera, ET was obtained under standardized procedures. Rectal temperature measurements were obtained from the same dogs. The central 95% RI was estimated using a robust statistical method with bootstrap-derived 90% CIs for the limits, an approach recommended for datasets with 40 ≤ n < 120 observations. Results: Utilizing data from 78 dogs, the estimated 95% RI for ET was 35.0 to 38.5 °C, with 90% CIs of 34.7 to 35.4 °C (lower limit) and 38.2 to 38.8 °C (upper limit). The 95% RI for RT was 37.5 to 39.7 °C, with 90% CIs of 37.3 to 37.8 °C (lower limit) and 39.5 to 39.9 °C (upper limit). Conclusions: These findings provide baseline ET screening limits from a moderate sample size. Instead of replacing established veterinary guidelines, our calculated RT interval validates the normal temperature status of our population. Temperatures outside these borders justify individual medical evaluation. Clinical Relevance: Population-based RIs for ETs and RTs of dogs are needed to assist veterinarians and researchers in interpreting ET and RT measurements and identifying dogs that might require further clinical examination. Furthermore, eye thermography might provide a practical, fast, and low-stress method for temperature evaluations.