Crib biting

Crib biting is one of the typical behavioural disorders of horses, usually caused by psychological trauma, lack of exercise, and inappropriate breeding. However, some horses also start to chew due to stomach ulcers. The lower neck muscles become tense and the horse swallows air into the oesophagus. This produces a sound that sounds like burping. However, new findings show that the air is not really swallowed, but escapes again without a sound when the muscles are relaxed. During the burping process, the horse’s brain releases endogenous opiates that calm the horse. In the process, the heart rate decreases and the horse is thus better able to cope with the “unbearable stress situation”.