Hot dogs : thermography in the assessment of stress in dogs (Canis familiaris)

Infrared thermography (IRT) represents a novel, not invasive method to investigate stress responses in animals. Despite the interest in the study of stress responses in dogs, the potential use of IRT in assessing dogs’ stress reactions has not been investigated so far. This study evaluates the potential use of IRT to assess dogs emotional responses to an unpleasant and stressful event. Following a preliminary test aimed at evaluating the correlation between eye-temperature and rectal temperature in dogs in a stressful situation, a sample of fourteen adult healthy dogs was observed during a standardised veterinary examination, carried out by an unfamiliar veterinarian in the presence of their owner. Their behaviour and eye temperature were recorded before the start of the veterinary visit, during and after the clinical examination. Dogs’ level of activity and stress related behaviours varied across the different phases of the visit; interestingly, dogs showed an increase in eye temperature during the examination phase, compared to both pre-examination and post examination phases, despite they had a significant decrease in their level of activity, and also showed freezing, when on the examination table. However, it also emerged that the thermographic camera, although remote and not invasive, was to some extent disturbing for dogs, as they showed avoidance behaviours, averting gaze and/or turning their head, exclusively when the thermographic camera was oriented to them. Thus, overall results suggest that IRT may represent a novel and useful tool to investigate negative emotional psychogenic stress in dogs, but with some potential restraints. This potential disturbing effect needs to be taken into account when planning IRT studies with dogs