Understanding equine stereotypies.

It is frequently asserted that equine stereotypies, such as crib-biting, wind-sucking and weaving, are caused by boredom. However, this explanation is too general to be of practical use in discerning the causes of each stereotypy or in devising management practices to prevent their occurrence. The majority of equine stereotypes start within one month of weaning when both the nutritional and social environment of the foal are substantially altered. Epidemiological research has revealed that the provision of low quantities of forage and minimal opportunities for social contact are associated with a higher reported prevalence of stereotypic behaviour. Experimental data also suggest that oral stereotypies develop in response to a low forage diet but this may be partially adaptative. Oral stereotypies may increase salivary flow therefore reducing the acidity of gastric tract and speeding the transit of ingested feed. Stereotypic horses may be less reactive to short-term aversive stimulation. Neither direct nor circumstantial evidence confirms anecdotal reports that horses copy stereotypies from each other. Surgical and pharmacological methods of prevention should not be attempted unless the underlying causes are removed.