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Pet Owner Version

Diagnosing Behavior Problems in Horses


Gary M. Landsberg

, BSc, DVM, MRCVS, DACVB, DECAWBM, North Toronto Veterinary Behaviour Specialty Clinic;

Sagi Denenberg

, DVM, DACVB, Dip. ECAWBM (Behaviour), MACVSc (Behaviour), North Toronto Veterinary Behaviour Specialty Clinic

Reviewed/Revised Mar 2019 | Modified Oct 2022
Topic Resources

Some “health” problems faced by horses are associated with behavior problems or unmet expectations about the animal’s behavior. Your veterinarian will need to rule out any possible health problems that could be causing your horse's behavior to change. To do this, they will complete a physical examination and may perform diagnostic tests, such as blood tests. In addition, your veterinarian will consider whether your horse is experiencing stress, which can alter normal body functions, behavior, and immune responses. Especially over time, stress can have various effects on health and behavior.

After ruling out a medical problem, your veterinarian will take a behavioral history. A behavioral history includes the following:

  • sex, breed, and age of the horse

  • age at onset of the problem

  • duration of the problem

  • description of the actual behavior

  • the frequency of the behavior (hourly, daily, weekly, monthly)

  • the duration of an average episode (seconds, minutes, hours)

  • the range of duration of episodes

  • any change in the pattern, frequency, intensity, or duration of episodes

  • any corrective measures tried and the response

  • any activities that stopped the behavior

  • a typical 24-hour schedule for the horse and owner, as well as any day-to-day variability

  • the horse’s breeding (to see if there are any signs of similar problems in the dam or sire)

  • environment and housing

  • anything else the owner thinks is relevant

To get a complete picture of the problem, it is important to discuss these points with everyone responsible for the horse's care, including barn personnel and trainers. It can also help to take a video of the behavior to show to the veterinarian.

In addition, you and your veterinarian should consider the "ABCs" of the behavior problem. What happens prior to the behavior (the Antecedent)? What is the Behavior? What happens immediately afterward (the Consequences)? Because behaviors can change as horses learn and mature, your veterinarian will also consider how the problem initially started.

Where to Get Help

Owners seeking help for a behavior problem with their horse can turn to several sources. The American Veterinary Medical Association recognizes a variety of specialties within veterinary medicine. Similar to specialties in human medicine, these include veterinarians who are board-certified in surgery, internal medicine, ophthalmology (eye care), dentistry, behavior, and many other areas of expertise. Most board-certified veterinary behaviorists work in veterinary colleges or private referral practices. To find a veterinary behaviorist that specializes in horses, please see the American Veterinary Society of Animal Behavior's Find a Consultant tool.

There are also veterinarians who are not board-certified, but who have a special interest in behavior. These veterinarians have a range of experience and expertise in the field, and many offer behavior consultations as a part of their regular veterinary practice.

There are also non-veterinarians who call themselves behaviorists and offer counseling on behavior problems of horses. Some have a doctoral or master’s degree in psychology or a related field, and some have earned a certification. Others, primarily horse trainers, have no formal education in behavior but offer advice on solving behavior problems. Owners who need help for their horse should ask about the background and training of the person offering the behavior consultation before setting up an appointment. Because many behavior problems in horses can be influenced by medical conditions, veterinarians are the professionals who can offer the most comprehensive care.

Defining the Problem

In order to properly diagnose a behavior problem, both you and your veterinarian must use the same definitions for the same behaviors. You both must also accurately recognize and describe the behaviors that are of concern. Video of the horse can ensure that such communication occurs. Your understanding and compliance are critical if horses with behavior disorders are to improve. Only when you recognize the behaviors leading to the problematic ones, can you avoid or prevent the provocative situation. Therefore, by viewing a recording of the problematic behavior, your veterinarian will be able to work with you to achieve more desirable responses and help treat the condition.

An abnormal behavior is one that is dysfunctional and unusual. This is different from a behavioral complaint, which is an undesirable but "normal" action.

Aggression in horses may occur as a threat or as an attack. There are various kinds of aggressive behavior in horses, such as fear aggression and inter-male aggression. Some types of aggression are normal (such as mother being protective of her foal), whereas others are inappropriate and abnormal.

Anxiety is the anticipation of future danger accompanied by signs of tension (vigilance, increased motor activity, and tense muscles). The focus of anxiety can be internal or external.

A horse in conflict has tendencies to perform more than one behavior at once. For example, a horse may want to approach a person to take a treat such as an apple, but be reluctant to get too close because it is nervous. The motivation for the conflict, except for extreme instances associated with survival functions (for example, eating), is often hard to identify in animals. Conflict might result in aggression or displacement behaviors (see below).

Displacement activity is the resolution of a conflict by performing a seemingly unrelated behavior. When a horse is in conflict between breeding and aggression or between aggression and fear, it will often perform an apparently irrelevant activity. Examples of these activities include grooming, feeding, scratching, pawing, and sleeping. Displacement behaviors can also occur due to frustration or for no apparent reason.

Dominance refers to competition over a limited resource (for example, access to a feed bucket or water trough). A higher-ranking animal can displace a lower-ranking one from the resource. Rank or hierarchy is usually defined by an ability to control the resource. A dominant animal is not the one engaged in the most fighting. Most high-ranking animals can be identified by the submissive behavior exhibited toward them by others in their group. Dominance terminology applies to communication between members of a single species (horse-to-horse) but does not apply to communication between species (human-to-horse). The concept of dominance is often overused and applied inaccurately.

Fear is a feeling of apprehension associated with the presence or proximity of an object, individual, or social situation. It is part of normal behavior and serves to protect animals from danger. Deciding whether the fear is abnormal depends on the context. For example, fire is a useful tool, and fear of being consumed by it is a normal behavior. However, if the barn were not on fire, such a fear would be irrational. If this fear was constant or recurrent, it would probably be considered an abnormal behavior. Normal and abnormal fears usually vary in intensity. The intensity of the fear increases as the real or imagined nearness of the object that causes the fear increases. A sudden, exaggerated, abnormal, fearful response is usually called a phobia (see below).

Frustration arises when a horse is unable to perform a behavior due to physical or psychological obstacles in the environment. When a horse is frustrated, it can respond with a displacement activity or signs of anxiety. This term, like dominance, is overused and usually undefined, which means it often is not very helpful when diagnosing a behavior problem.

Most fearful reactions are learned and might be unlearned with gradual exposure. Phobias, though, are profound, fearful reactions that do not diminish either with gradual exposure to the object or without exposure over time. A phobia involves sudden, all-or-nothing, exaggerated, abnormal reactions resulting in panic. Phobias may develop quickly or over time, but once established they are characterized by immediate and intense anxiety. Fear may develop more gradually and, within an episode of fearful behavior, there may be more variation in intensity than would be seen in a phobic reaction. Once a phobic event has been experienced, any event associated with it or the memory of it is sufficient to generate the reaction. Even without re-exposure phobias can remain at or exceed their former high level for years. Phobic situations are either avoided at all costs or, if unavoidable, are endured with intense anxiety or distress.

Stereotypic behaviors are repetitious, relatively unvaried behaviors that have no obvious purpose. They are usually derived from normal behavior, such as grooming, eating, or walking. Stereotypic behaviors may occur in situations of conflict or frustration related to an animal's environment or care, such as confinement, barren environments, stress, and being taken from its mother too soon. Example behaviors are weaving, stall walking (pacing), and cribbing. These behaviors are abnormal because they interfere with the normal functioning of the animal.

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