Urinary oxytocin as a noninvasive biomarker of positive emotion in dogs

► Dogs were injected intravenously with exogenous OT. ► We measured the time-lapse in the concentration of plasma OT relative to urinary OT. ► The highest concentration of urinary OT occurred 60 min after intravenous injection of exogenous OT. ► To evaluate the influence of stimuli on urinary OT, we subjected the dogs to eating, exercising and stroking. ► These stimuli significantly increased urinary OT concentrations in dogs.