Respostas autonômicas e comportamentais ao estresse sonoro agudo em cães de companhia com histórico de fobia a sons de trovão e/ou fogos de artifício

Abstract

Stress is a situation caused by a challenge in which a body is subject. And despite the stress response is essential for homeostasis, the persistence of the stressor stimulus or exaggerated response can induce deleterious consequences. A phobia is considered an anxiety disorder where the fear (emotional state in response to a situation of danger) is persistent and excessive which results in increased reactivity to stress. In this context many stimuli are considered stressors in dogs and the exposure to noise stimuli as thunder and fireworks is a natural choice for the study of reactivity to stress. Thus, we have evaluated the reactivity of companion dogs with history of phobia of the thunder sounds and/or fireworks to an acute acoustic stress model, by analysing the variability of Cardiac Interval (VCI) and behavioural parameters. We used 28 companion dogs, different breeds, 2 to 6 years old, weighing 10 to 30 kg, with no signs of other diseases, from volunteers owners of City of Seropédica-RJ. The dogs were selected by questionnaire on the intensity of the fear of thunder and fireworks, divided in phobic or not phobic and between the stimuli sound of thunder or fireworks. The sound stimulus consisted of a standardized recording from 2.5 minutes to a maximum intensity of sound of 103-104 dB. For the analysis of VCI, RR intervals were recorded through frequency meter (Polar ® RS800CX model), stored and analysed using CardioSeries 2.4.1 sofware. We also evaluated the profile of the owners, general characteristics (weight, age, race and gender) and handling of animals. No differences were found in the socioeconomic profile of the owners, or general characteristics or animal handling between phobic and non-phobic dogs. The sound stimulus (thunder or fireworks) was able to induce a significant increase in LF / HF ratio in both non-phobic animals and phobic animals. However, the magnitude of the sound-induced increase in the LF/HF was significantly higher in phobic than in non-phobic animals. The acute sound stress model produced an increase in the behaviour of surveillance, trembling and hiding. Only phobic animals submitted to fireworks sound model had significantly more intense behavioural responses than non-phobic dogs in the behaviours: Shivering, Hiding, Surveillance and Salivation. Behavioural responses described by the owners and shown by dogs during the stress model were correlated only in the behaviours: Shivering and Hiding. Significant correlation was found between the ratio values LF / HF and the following behavioural parameters induced by sound in the laboratory: Panting, Shivering, Hiding, Escape, Shockwave, Surveillance, Salivation and Startle. The sound model was able to induce behavioural and autonomic responses of stress and it shown a good tool to measure the magnitude of stress responses in the companion dogs with history of phobia of thunder and fireworks sounds and it can be used in the study of new therapeutic targets.