Crib-biting falls within the well-recognised category of stereotypical abnormal behaviour.

Considered an unsoundness, crib-biting is the term given to a horse taking hold of a fixed object, such as a fence or top of a stable door, with his teeth and pulling back on it, tensing the neck muscles and sometimes swallowing air. It is common for horses to crib-bite around feeding time, although the behaviour can occur at any time.

Crib-biting is common — between two and 15% of domesticated horses kept in stables around the world exhibit this behaviour, although this varies with breed and management. There is a suspicion that the tendency is inherited, but also a belief that horses learn to crib-bite from others in the yard.

Crib-biting and breeding

Researchers in Helsinki, Finland, have studied the prevalence of crib-biting in Finnhorses, a cold-blooded draught breed that has had a closed and well-documented studbook for more than
100 years.

They looked at the breeding and lineages of horses that were established crib-biters and compared them with non-crib-biters that were matched for age, type of work and management. Horses were not classed as non-crib-biters until they were 10 years old, since the habit can appear in horses up to that age.

It was clear that for this breed — and probably for all others — crib-biting is strongly linked to breeding. In other words, there is a clear genetic predisposition or tendency to crib-bite that can be inherited and passed on to succeeding generations.

But it is not a simple matter of straightforward inheritance, since the study shows that several genes must be involved and that the expression of crib-biting is not just a result of genetics. A horse may inherit the tendency to become a crib-biter, but there will have to be stresses or anxieties in the individual horse that precipitate the actual behaviour.

This article was first published in Horse & Hound magazine (13 November 2014)