Effects of Olfactory and Auditory Enrichment on Heart Rate Variability in Shelter Dogs

Abstract

Animal shelters can be stressful environments and time in care may affect individual dogs in negative ways, so it is important to try to reduce stress and arousal levels to improve welfare and chance of adoption. A key element of the stress response is the activation of the autonomic nervous system (ANS), and a non-invasive tool to measure this activity is heart rate variability (HRV). Physiologically, stress and arousal result in the production of corticosteroids, increased heart rate and decreased HRV. Environmental enrichment can help to reduce arousal related behaviours in dogs and this study focused on sensory environmental enrichment using olfactory and auditory stimuli with shelter dogs. The aim was to determine if these stimuli have a physiological effect on dogs and if this could be detected through HRV. Sixty dogs were allocated to one of three stimuli groups: lavender, dog appeasing pheromone and music or a control group, and usable heart rate variability data were obtained from 34 dogs. Stimuli were applied for 3 h a day on five consecutive days, with HRV recorded for 4 h (treatment period + 1 h post-treatment) on the 5th and last day of exposure to the stimuli by a Polar® heart rate monitor attached to the dog’s chest. HRV results suggest that music activates both branches of the ANS, which may be useful to relieve both the stress and boredom in shelter environments.

A Review on Mitigating Fear and Aggression in Dogs and Cats in a Veterinary Setting

“…This conclusion was not only based on a critique of study design and reporting of the analysis of the included studies (e.g., measuring a large number of variables without correcting for type 1 error), but also because for Feliway spray, the manufacturer stated that strong-smelling disinfectants, bleach, biological washing powder, detergents or deodorisers—products that are commonly used in a veterinary setting—can interfere with the product’s functioning (reviewed in [ 105 ]). Moreover, several recent controlled studies could not confirm calming effects of Adaptil ® on dogs in other contexts including separation from the owner and shelter housing [ 149 , 150 , 151 ]. According to a systematic review, the effectiveness of pheromones in dogs and cats on fear behaviour could not be demonstrated in the majority of studies due to a lack of adherence to scientific quality criteria [ 152 ].…”

Heart rate as a measure of emotional arousal in evolutionary biology

“…Heart rate can be used to monitor arousal levels of individuals when evaluating the effectiveness of measures intended to reduce stress, for example, when enrichment or other changes are introduced in animal shelters or laboratories. In kennelled dogs, the presentation of auditory and olfactory enrichment decreased heart rate and changed heart rate variability, indicating stress reduction [52,53], and mice, Mus musculus , that were housed in enriched conditions had a significantly lower heart rate compared to individuals housed under minimal husbandry conditions without enrichment and periods of individual housing [55]. Generally, social isolation can cause significant increases in heart rate (alpaca, Vicugna pacos : [90]; dogs: [78]; cattle: [54]; cynomolgus monkeys, Macaca fascicularis : [91]; goats: [18]; wolves [78]).…”

“…[51]dogs, Canis familiaris wearable heart rate beltAmaya et al . [52]; Bowman et al . [53]housing conditioncattle, Bos taurus electrodes attached to skin surface, connected to cardiotachometerBoissy & Le Neindre [54]mice, Mus musculus implanted radio-transmitterMeijer et al .…”

Do Canine Behavioural Assessments and Characteristics Predict the Human-Dog Interaction When Walking on a Leash in a Shelter Setting?

“…In this study, there were difficulties in accurately identifying the underlying emotions and motivation of the dog. Similar to the cortisol level and heart rate variability, our leash tension meter may only be able to differentiate the relaxed and aroused states of the dog but cannot specify whether the arousal is due to excitement, anxiety or fear [ 81 , 92 ]. To precisely interpret the underlying emotion and motivation of the dog, a better video quality that records the face and the entire body of the dog, environment and the context of the interaction is needed.…”