Horses in the wild are herd animals designed to range across large areas of land seeking food and water, spending much of their day grazing. Modern management techniques enforce very different behaviour, with horses restricted to small paddocks, yards or stables often without close contact with other horses, and fed high grain, low roughage diets. Horses can develop a range of behaviours that are thought to be associated with these management practices. Some, such as crib biting, windsucking and weaving, are called stereotypes.
Crib biting involves the horse biting onto or resting their upper incisors (front teeth) onto wood or other objects, arching their neck, relaxing their throat and drawing air into the upper oesophagus. They usually make a characteristic grunting noise as the air is drawn in.
Windsucking is a similar behaviour to crib biting, however they do not grip onto an object. These terms are often used synonymously.
Why do horses windsuck or crib bite?
Studies have been performed to determine why horses develop behaviours such as these:
- The act of windsucking or crib biting activates narcotic and dopamine receptors (‘feel good’ receptors) in the central nervous system, thereby rewarding the behaviour. Studies have demonstrated decreased severity of the behaviour when treatment for human drug and alcohol addictions are given, with the behaviour recurring when medication is stopped.
- High grain low roughage diets lead to an increase in stomach acidity. It is possible that alkaline saliva produced when crib biting or windsucking helps to neutralize the stomach acid.
Crib biting and windsucking are often referred to as vices and may have a significant effect on the sale-ability of horses, especially pleasure horses.
Issues that may arise secondary to crib biting or windsucking are
- Wear to the upper incisors.
- Weight loss due to less time available to eat (this may be an increased issue where horses are housed in groups).
- There is a perception that affected horses have an increased susceptibility to colic which is supported by some studies.
Managing Crib biting and windsucking
Unfortunately at this stage there is no cure for these behaviours, however there are a range of management methods used.
- Environmental stimulus – increased access to turnout, increased availability of toys, increased access to other horses, increased access to low grain, high roughage feed eg plenty of hay or pasture
- There are a variety of collars available on the market that when fitted firmly around the throat prevent flexion of the neck. Unfortunately it is often necessary to tighten these collars regularly, and they can lead to damage to the underlying skin. Some collars are fitted with aversion therapy such as electric shock therapy, however I find it hard to recommend these.
- Surgical techniques are described that involve cutting the muscles and nerves involved, however studies have shown that some horses will learn alternative ways to continue the behaviour.
- Removing access to hard surfaces for the horse to grip (eg by running an electric wire along the top of post and rail fences) may reduce the incidence of crib biting but will have little effect on windsucking behaviour.
Weaving and stall walking
Weaving involves standing and repetitively shifting their weight from side to side, often with a corresponding side to side movement of the head and neck. Stall walking involves compulsive walking around the stall.
Weaving and stall walking may lead to weight loss due to decreased time available for eating. It may also lead to increased wear to the flooring of the stable or yard.
Management may include environmental enrichment, access to other horses and increased roughage in the diet. Strategic barriers may reduce the behaviour in some horses.
In the event you notice your horses developing any of these habits look to your management program, if you catch it early it may be possible to redirect the behaviour.