An exploratory study of competition scores and salivary cortisol concentrations in Warmblood horses

The main objective of this explorative study was to describe the relationship between competition scores and salivary cortisol concentrations in young horses during dressage and showjumping competitions. The study also investigated whether the diurnal rhythm of salivary cortisol concentrations was affected by competition over consecutive days compared with the home environment. Saliva samples were collected from 126 dressage horses and showjumpers in their home environment and at 3 different events. The relationship between scores given by judges at the competition and cortisol concentrations at the event was assessed. The results demonstrated that competition scores correlated positively to baseline cortisol concentrations at one of 3 events (r = 0.53, P < 0.001). Salivary cortisol concentrations followed a diurnal rhythm with the highest concentrations measured in the morning and the lowest in the evening, both at home and in the competition environment (P < 0.05). Salivary cortisol concentrations were greater during the competitions than at home (P < 0.05) except at one event where showjumpers did not increase between home and competition. Dressage horses had the highest baseline cortisol concentrations at competition, and exercise caused cortisol concentrations to increase in both showjumpers and dressage horses (P < 0.001). In conclusion, the diurnal rhythm in salivary cortisol concentrations was maintained in the novel environment. Dressage horses demonstrated greater baseline cortisol concentrations at competition than showjumpers, suggesting that they may perceive the novel environment as more stressful. Furthermore, there was no consistent relationship between baseline salivary cortisol concentrations and competition scores across the events.