Horses Blink Less, Twitch Eyelids More When Stressed

front of the horse in an attempt to startle the animal. In the next the horse was visually separated from its herd for a few minutes. Finally the horses food was withheld for three minutes at feed time while its herdmates were allowed to begin eating.
Researchers attempted to startle the horses by throwing a ball in front of them.
The researchers filmed the horses watching for changes in eye and ear movement head tilt and general restlessness.
They found that withholding the feed for a few minutes was the most stressful for the horse as indicated by its increased heart rate restlessness and head movement. Conversely separation and the startle test evoked little response.
Its important to remember these were riding school horses so they were used to being startled and being separated. But the withholding of food was new so thats likely why they became stressed she said.
When researchers reviewed videos of the horses eyes during feed withholding they noticed the horses blinked less but twitched their upper eyelids more.
On average the horses full blink rate decreased to an average of five blinks per minute during the stress compared to the eight to nine times per minute when relaxed. During the feed restriction when the horses felt the most stress their eyelid twitches increased from an average of two twitches per minute to six twitches per minute. There was no increase in eyelid twitches with the other stress tests.
Merkies said she hopes her teams finding will help horse handlers looking for simple
ways to gauge their animals moods.
Theres no one measure that is going to tell us everything but this is another tool we can add to the toolbox that we can use together to understand our animals better she said