The effect of dog-human interaction on cortisol and behavior in registered animal-assisted activity dogs

Background: The effect of animal-assisted activities (AAA) on the animal participants has been minimally investigated and the welfare of these animals has been questioned. Cortisol, in conjunction with stress-associated behavior, has been utilized as an objective assessment of animal welfare.

Objective: Salivary cortisol and behavior in AAA dogs were measured to test the null hypothesis that salivary cortisol concentration and behavior are not different in an AAA environment compared to home or neutral environments.  Hair cortisol was measured in AAA dogs to test the null hypothesis that there is no relationship between hair cortisol and salivary cortisol.

Methods:  Fifteen healthy adult dogs registered with an AAA organization were recruited.  A hair sample was collected from each dog upon enrollment.  Saliva samples were collected from each dog every 30 minutes, starting 30 minutes prior to and 30 minutes after a standardized 60 minute session across 3 settings: an AAA session (AS) for college students in the communal area of a residence hall; a neutral session (NS) located in a novel room without interaction with a stranger; and a home session (HS).  Each session was videotaped continuously and behaviors were coded at three separate 5-minute intervals while the dog was petted by a stranger in the AS or handler in the NS and HS.

Results:  Salivary cortisol levels were not different in the AS compared to HS, but were significantly higher in the NS compared to AS and HS.  Dogs exhibited significantly more standing and ambulating behavior in the AS compared to HS.  Salivary cortisol level was negatively correlated with panting and standing at specific time points in the NS and AS, respectively.  Hair cortisol level did not correlate with salivary cortisol level at any time point in any of the settings.

Conclusions:  During a 60 minute AAA session, salivary cortisol concentration and stress-associated behavior were not different compared to when dogs spent the same amount of time in the home setting, suggesting that they were not stressed when being used as AAA animals. The physical environment may be an important consideration when evaluating the effect of AAA on dogs.  Hair cortisol did not correlate with salivary cortisol, suggesting that hair may not be a representative predictor of cortisol in these environments.  Additional investigation is required to support cortisol and behavior as measures of stress and welfare in AAA animals.