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Pet Owner Version

Treatment of 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

The diagnosis, treatment, and expected outcome of a behavior problem vary depending on the underlying issue. Early on, owners will usually need to avoid situations that trigger the abnormal behavior. After implementing treatment techniques, the problematic situations might be slowly reintroduced under the recommendations of the overseeing veterinarian. Repetition of the behavior tends to worsen the problem, especially if the behavior successfully accomplishes the intended goal (for example, a horse that acts aggressively to avoid being handled). Treatment for abnormal behaviors takes time and commitment from horse owners. Quick fixes or "magic pills" do not exist for behavior problems. The environment may need to be modified to keep the horse away from areas where the problem occurs or away from stimuli that trigger the problem. In addition, the safety of people, other animals, and the horse itself must be considered, especially in the case of aggression. Modifying a horse's behavior involves behavior modification techniques to promote and reward desirable behaviors; the use of products that improve safety, reduce anxiety, or facilitate improvements; and, possibly, medications. With treatment, improvement is usually a slow and gradual process.

Behavior Modification in Horses

The most commonly used techniques to modify animal behavior include habituation, extinction, desensitization, counterconditioning, response substitution, and shaping. A behavior modification technique called flooding (see Flooding, below) is only used rarely because it has a high potential to make animals worse. While it is claimed that punishment is frequently used with varying degrees of success, few people correctly employ punishment. For punishment (for example, screaming at the horse) to be successful, it must occur sufficiently close to the start of the behavior. Most punishments are inappropriate in context, duration, or time of application. Even when used correctly, punishment may only suppress the unwanted behavior, rather than eliminate it completely.

Most of the humane, passive, or positive techniques involved in behavior modification are not hard to learn and are successfully employed as preventive techniques. They do require a regular investment of time and effort, however. The following is a short review of the basic principles involved in the techniques, and their associated strategies.

Habituation is an elementary form of learning that involves no rewards. It is merely the ending of or decrease in a response to a stimulus that results from repeated or prolonged exposure to that stimulus. For example, horses placed in a pasture bordering a road may at first run away when traffic passes, but eventually learn to ignore it. A horse that habituates to one type of sound does not, as a consequence of this habituation, become habituated to other sounds. Habituation is distinct from failing to respond to stimulation as a result of fatigue or injury. The effects of habituation are generally long lasting. If a horse is repeatedly exposed to a potentially harmful stimulus (such as to a predator) without being harmed, habituation does not generally occur. Responses to dangerous stimuli seem to have an inherited resistance to habituation. If the fear response is too intense, instead of habituation the animal may become increasingly more fearful of the stimulus. This is termed sensitization.

Spontaneous recovery is associated with habituation. If there is a long time between when a horse has experienced an event to which it had habituated and re-exposure to the same event, the horse may again react.

Conditioning refers to associations between stimuli and behavior. For example, a horse that touches an electric fence will receive a painful shock. It will quickly learn to avoid touching the fence. The sight of the fence itself will then become associated with the shock. Classical conditioning can occur in both positive and negative ways. An example of positive response is the pairing of an object with a treat. If the horse sees an object every time that it receives a treat, it will react positively to the object in the future, even if a treat is no longer present.

Reinforcement is any event that increases the chance that a certain behavior will be repeated. When positive reinforcement (such as a reward) is used in training, there is a positive relationship between the behavior and its consequences. The more the horse does a behavior, the more it gets positive reinforcement and what it gets is good. This makes that behavior increase. A negative reinforcement (which is mistakenly thought of as punishment by many people) is something unpleasant that increases a behavior when it is removed. For example, most horses find the application of spurs to be painful. When the horse starts moving, the spurring stops. This reinforces the behavior the rider wanted. Over time, the horse will start moving as soon as the spurs are applied.

Second-order reinforcers are signals that can be used at a distance to let the horse know that the reward is coming. Commonly used second-order reinforcers are words, such as “good girl,” hand signals, and whistles. By carefully pairing these with a primary reward (such as food), second-order reinforcers encourage the same response that the reward would.

Extinction is a response that stops when the reward is removed. For example, if a horse was used to getting a carrot as a treat for coming up to the fence of a paddock, but then the owner stopped giving it a carrot, the horse would eventually stop coming over to the fence. The more valuable the original reinforcer, the longer the reinforcement has been continuing, and the more uncertainty there is about whether the reward has been truly removed, the greater the resistance to extinction.

Resistance to extinction (and thus a continuation of the behavior) can also occur even without reinforcement if the reward was good enough and was tightly linked to the behavior. Because there is often an association between getting the reward and the intensity of the behavior, the intensity or frequency of the behavior you are trying to eliminate usually increases at the beginning of extinction. In other words, a behavior you are trying to extinguish may get worse before it gets better. It is critical that you do not give in. Giving in will only make extinction more difficult. The horse will learn that, although your threshold has increased, the horse can override it by working harder.

Overlearning is the repeated performance of an already learned behavior. It is frequently used in training for specific events. Overlearning accomplishes 3 things: it delays forgetting, it increases the resistance to extinction, and it increases the chance that the response will become an automatic or “knee-jerk” response in similar situations. This aspect can be useful in teaching a horse to overcome fear or anxiety.

Shaping is a training technique that works well for horses that do not know what response is desired by the trainer. Shaping works through gradual approximations and allows the horse to be rewarded initially for any behavior that resembles the desired behavior. For example, when teaching a horse to load on a trailer, at first you might praise and stroke the horse for just taking 1 or 2 steps toward the trailer’s ramp. Next, you would reward it for walking calmly up to the ramp. Finally, the horse would be rewarded only for completely entering the trailer.

Desensitization is a way to teach a horse to tolerate a situation by exposing it to the problem when it is minimized or reduced to a level that does not cause fear. As long as the horse does not act fearful, the intensity can be slowly increased in a series of small steps. For example, a horse that is fearful of having its hooves picked may need to be desensitized to having its feet handled. This could be started by first rubbing and massaging the upper leg, then gradually working down to the hoof. The leg could also be picked up and held for a few seconds, gradually increasing that to several minutes over a series of training sessions.

Counterconditioning is a method for reducing undesirable behavior by teaching the horse to replace it with another more favorable behavior. In the hoof-picking example, the horse will learn faster if it is first taught to stand calmly and relax in exchange for a treat. The horse must be absolutely quiet and calm, and convey by its eyes, body posture, and ear position that it is not alarmed. Once this behavior is learned, the desensitization is added by handling the leg closer and closer to the hoof. If at any time the horse starts to become anxious or agitated, the trainer should handle a higher part of the leg until the horse relaxes again. There is no point in forcing the horse to submit to handling if it is clearly distressed. Relaxation is the first step to changing the behavior. Counterconditioning coupled with desensitization is an effective yet time-consuming technique. The exercises must be repeated often so that the fearful response decreases until it disappears.

Flooding is prolonged exposure to a stimulus until the horse eventually stops reacting. This is the opposite of the approach taken in desensitization. It is far more stressful than any of the other treatment strategies and if not used correctly could make things worse. This technique should be used only by a professional and only as a last resort.

Punishment is also known as aversive conditioning. It is any unpleasant event that lowers the chance that a behavior will be repeated. It can involve applying something unpleasant (called positive punishment) or removing something that is desirable or appealing (called negative punishment). Punishment is not the same as negative reinforcement (see above). To be most successful, punishment must occur as early as possible (within a few seconds of the start of the behavior), and it must be consistent and appropriate. Critical factors in punishment include timing, consistency, appropriate intensity, and the presence of a reward after the undesirable behavior ends. This is the most frequently ignored part of treatment for people whose horses have behavior problems. Owners often resort to physical punishment as the first choice, but punishment does not need to be physical. Furthermore, punishment is just as hard to use correctly as counterconditioning and desensitization. Punishment is never an “easy out” and has a high chance of failure. It can also lead to other negative consequences, such as increased fear or aggression. If a person applies the punishment, the horse may become fearful of that person or only avoid the behavior when that person is present (and continue the behavior in the person's absence). This is helpful, because relationships with people should always remain positive. In addition, punishment cannot be used to achieve desirable behaviors, only to stop what is undesirable. However, before focusing on how to stop what is undesirable, the owner should first focus on providing a desirable alternative.

Response substitution involves the replacement of an undesirable response with a desirable one. This often involves training a desirable behavior, then prompting the horse to perform that behavior during times when the undesired behavior typically occurs. If the horse responds favorably, the horse is rewarded. Alternatively, the horse could be trained to do a task that is incompatible with the undesired behavior. For example, teaching a horse to back up instead of bolting.

The Premack Principle states that more likely behaviors will reinforce less likely behaviors. If a less desirable behavior must be performed in order to accomplish a desired one, it is more likely that the less desirable behavior will occur. For example, a horse that wants to walk ahead can be taught that walking on a slack rein can result in this behavior.

Use of Medication to Treat Behavior Problems

Your veterinarian may, in some cases, prescribe medication to help treat a behavior problem in your horse. Drugs may help normalize a horse's emotions and improve your ability to train anxious, overreactive, or fearful animals. In some cases, they can also improve a horse's welfare. Drug treatment for almost any behavior change is most useful when combined with behavior modification, which is how new behaviors are learned.

In recent years there has been an increase in the use of medication to treat a variety of behavior problems in domestic animals. There are a number of potential disadvantages to the use of medication for treating these problems, however, and you should know that there is no “magic bullet” that will easily and quickly solve the problem. The limitations of medication use include the potential for adverse effects, the cost, the need to treat for a considerable length of time before the medication takes effect, limited information on what medication is most effective, and the potential that the problem will reappear once the medication is withdrawn.

Your veterinarian can discuss whether medication might be appropriate for your horse.

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