Hot dogs: Thermography in the assessment of stress in dogs (Canis familiaris)—A pilot study

How good is this food? A study on dogs' emotional responses to a potentially pleasant event using infrared thermography

“…To minimize extraneous noise and disturbance, testing was conducted on weekends over a period of four months. The testing environment was air-conditioned and thus temperature (22 °C) and humidity (40%) remained constant during the procedure [56].Owners were asked not to feed their dogs for at least four hours prior testing.…”

“…Superficial temperature was measured using infrared thermography (IRT), a remote and non-invasive technique that detects changes in peripheral blood flow. This technique has been recently used to explore physiological correlates of stress and emotions in animals [36,[48][49][50][51][52][53][54][55][56] with only one study on dogs [56],whereas heart rate and heart rate variability are regarded as suitable tools to investigate the role of ANS in the modulation of affect and emotion [17,20,35,55,57,58].…”

“…Making predictions on eye temperature changes is difficult, given that the available evidence is relative to a variety of body surface areas, tools and species tested with opposite results (comb in hens: [36]; nose in cows: [41]; eye in dogs: [56]; eye in horses: [54]; nose in macaques: [48,52,64]). …”

“…However, in dogs eye temperature correlates with core body temperature [56] and thus it is possible that eliciting an attentional state would result in an increase in eye temperature due to a general state of arousal. To test these predictions, dogs' eye temperature, heart rate, heart rate variability and behavior were recorded prior (Phase 1), during (Phase 2) and after (Phase 3) food treats delivery.…”

“…To evaluate whether the thermographic camera directed towards the dogs' muzzle could be perceived as stressing (see [56]), during coding, a marker indicating the presence of the thermographic camera accompanied each behavioral element. The dogs' behavior was coded from videos by one of the authors (T.T.)…”