Recent work conducted at the University of Veterinary Medicine, Vienna, and published in the journal Hormones and Behaviour, examined the stress suffered by young horses being backed.

Stress levels were measured by examining the horses’ heartbeats and the levels of the stress hormone cortisol in their saliva.

In looking at heartbeats, researchers considered not only their frequency but also the short-term fluctuations in intervals between the beats, which have previously been shown to be a good indicator for stress.

Unsurprisingly, it was found that the start of training was a stressful period.

Initial lungework caused only a moderate amount of stress, but this rose markedly when the rider first mounted.

It seems likely that the horse interprets the first mounting of a rider as a potentially lethal attack by a predator, from which it is unable to escape. In addition, the rider is outside the horse’s field of vision.

When the horse and rider walk or trot forwards, the level of stress decreased.

It therefore appears the horse adapts rapidly to the idea of being ridden and that — as is the case for humans — exercise may help relieve stress.

To find out how stress affects competition horses’ performance, don’t miss the Vet Clinic in this week’s Horse & Hound, 16 December ’10