To assess stress in horses, a method of monitoring eye blinks (full and half) and eyelid twitches while collecting saliva and blood samples before and after annual intensive police training was carried out. This noninvasive monitoring method was used to determine whether blood collection, which is considered invasive, is more stressful for horses than saliva collection. We discovered no significant difference in stress related manifestations between saliva sampling and blood collection in our study. In both cases, sampling (blood and saliva) reduced the number of full and half eye blinks. Based on our hypothesis, we expected a statistically significant changes in the number of eye blinks and eyelid twitches as the number of potential stressors increased (in our case, we considered police training and sampling). Saliva cortisol levels, on the other hand, revealed that police training for horses was not stressful. The method of measuring eye blinks and eyelid twitches appears to be an appropriate alternative method for monitoring stress factors in horses.
Keywords: Blood; cortisol; eye blinks; eyelid twitches; saliva.