Editor’s note: This article is part of TheHorse.com’s ongoing coverage of topics presented at the 2012 Alltech Symposium, held May 21-23 in Lexington, Ky.

Could a chemical imbalance be responsible for the development of stereotypic behaviors in horses? According to one researcher, a dopamine modulation dysfunction is being implicated as a risk factor for stereotypic behavior development.

At the 2012 Alltech Symposium, held May 21-23 in Lexington, Ky., Sebastian McBride, PhD, researcher at the University of Cambridge in England, discussed dopamine’s potential role in equine stereotypic behaviors.

Types and Development of Stereotypies

McBride said stereotypic behavior is present in about 7-9% of the horse population. Three of the most common stereotypies are:

  • Cribbing (an oral stereotypy that involves the horse sucking air into his esophagus);
  • Weaving (a locomotor stereotypy that involves lateral movement of the head and shifting weight back and forth on the forelimbs); and
  • Stall walking (a locomotor stereotypy that involves a highly invariant movement pattern around the stall or pen).

McBride suggested that stereotypic behaviors often develop as a result of chronic stress or husbandry practices that restrict feeding, social contact, and/or locomotor activity. He said these behaviors are goal-directed and occur when a horse gets "stuck" between the appetitive (having the urge to carry out a task) and consummatory (actually carrying out the task) portions of goal-directed behaviors.

For example, horses evolved to