Crib biting is a stereoptypical behaviour (also known as a stable vice). Sterotypical behaviours or stereotypies are described as repetitive behaviours which have no apparent function.
Crib biting is when horses use their incisor (front) teeth to grab onto solid objects and ‘gulp’ in air. The objects they can grab onto include:
- Stable doors
- Fence posts
It is therefore a problem which can happen both in the stable and out at grass. Crib biting is very closely linked with windsucking as the same chemicals are released in the brain. When high-grain diets are fed it stimulates endorphin release which in turn causes dopamine to be released. Crib biting is then performed to mimic the dopamine release. Other than a grunting noise, the hypertrophy of muscles on the underside of the neck and the unnatural wear of the incisor teeth there are no real adverse side effects. It becomes a habit as dopamine is released into the blood stream when a horse is windsucking, horses can soon become addicted to this dopamine release.
Recently there has been links made between gastric ulcers and windsucking. It is thought that horses with gastric ulcers seek the dopamine release which is associated with eating as they desperately want to buffer the stomach acid.
Once a horse starts crib biting it is very hard to make them stop as a habit will have formed. Helping them to maintain a healthy gut is the main objective with a crib biting horse. It is therefore important to minimise the risk of gastric ulcers so that they do not become worse.
The best way is to increase the horses forage intake and chewing time as chewing stimulates saliva release. Saliva contains bicarbonate which buffers the stomach acid so that ulcers do not form. Ideally horses should be fed ad lib hay so that there is no risk of gastric ulcers. If an animal is overweight the hay can be soaked so that it contains very few nutrients as long as a broad spectrum vitamins and minerals supplement is being fed.