Confinement can be stressful for some dogs and this can lead to behavioural issues and poor welfare. A key component of the stress response is behavioural arousal, characterised by increased alertness and sensory sensitivity. This makes behavioural observations a useful tool to assess stress, as they provide insight into an animal's internal state. Auditory enrichment has been shown to reduce arousal-related behaviour in dogs, but it is not clear if specific characteristics of a music track, such as tempo and/or pitch, produce these effects. The aim of this study was to compare behavioural responses of dogs to music tracks played with different characteristics (high pitch, low pitch, fast tempo, and slow tempo), as well as white noise and a control. Pitch and tempo modifications were applied to ten piano music songs and the six treatments (four different treatment-song combinations, white noise, and control) were presented daily, for ten minutes each, to ten dogs over ten days. Behavioural changes seemed to be driven by low-pitch tracks, which increased the level of alertness of the dogs. These findings could be related to the Morton's motivations-structural rules: harsh, low frequency vocalisations signal aggressive motivations in mammals. Dogs may have perceived low-pitch tracks as more unsettling and were therefore more active and alert when listening to them.
Keywords: alertness; arousal; canine; white noise.