aggression | cribbing and windsucking | pawing and kicking | pica | rejecting a foal | self-inflicted injuries | stall walking, circling, or weaving | trailering problems | counterconditioning, desensitization, and reinforcement |
Introduction:
Horses are social animals by nature. In the wild, they live in groups consisting of one to several stallions, several mares, and the mares’ young offspring. As the offspring (colts and fillies) mature, they typically leave the original herd and form other herds. This social maturity occurs at about 5 years of age. Young stallions form new herds, with the highest-ranking (dominant) stallion usually the first one to accept a young mare into the herd. Additional young mares may join this herd or other established herds. Horses that live in the wild almost always stay with other horses. The exception is older or sick stallions that may live alone.Dominance (hierarchical) ranking within a herd depends on numerous factors. In general, these factors include age, sex of the horse, length of time being in the herd, size of the horse, and social rank of the mother (mare). In addition, dominance ranking in stallions is determined by access to mares. Dominance ranking in mares within a herd is determined by their effect on the herd’s behavior and activity, such as locating resources (grass and water holes). These factors are important to analyze when evaluating behavior problems that may arise in stabled horses.
Since horses did not historically exist in confined areas and due to their need for social interaction with other horses, many behavioral problems may develop when horses are confined. When free-ranging, horses spend greater than 60% of their time eating (foraging) and wandering to find feed. The remainder of their day is spent standing, lying down, or playing. Play activities differ between males and females. Horses’ play activities also develop with maturity. Horses less than 3 months old usually play alone. Playing with other horses begins between 3 and 4 months of age, with colts playing more than fillies. Colts also interact differently than fillies. Colt play primarily involves fighting and mounting, while filly play is usually focused on running and grooming. Fillies groom other fillies and colts, while colts limit their grooming to fillies.
Even under confined conditions such as stabling, horses show similar behaviors as previously described. If these social behaviors are not understood and addressed, the following behavioral problems may develop:
Aggression Towards People or Other Horses
: The most common causes of aggression towards people and other horses are the result of sexual behavior (including aggressive stallions), dominance behavior, and fear. It is important to identify which one of these is the cause for the aggression before attempting any treatment. Some aggression associated with sexual behavior and establishing dominance is a normal attribute of horses of both sexes. Dominance over people should be considered abnormal and severely dominant horses are often too dangerous to keep. Fear aggression can be caused by environmental influences (abuse or severe treatment) or by things that naturally scare the horse such as sudden movements, inability to see, loud noises, and predators.Treatment for aggression includes counterconditioning, desensitization, and positive reinforcement (see the end of this discussion for details on these techniques). Problems associated with sexual behavior are often controlled by castration, ovariohysterectomy (spaying), or using hormones such as progestins.
Cribbing and Windsucking: Cribbing (also known as crib biting) and windsucking are common behavior problems in horses. Cribbing is manifest when a horse opens its mouth, places the chewing surface of its upper teeth on a horizontal surface, and flexes its neck with or without swallowing air. Windsucking is similar except for the fact that the horse does swallow air and may not require a surface to anchor itself on while swallowing. In this discussion, the terms cribbing and windsucking will be used interchangeably.
The cause of cribbing is not known, but is suggested to be related to the horse’s neurologic and chemical system. Specifically, horses that crib have lower internal levels of the chemical opium (opiates). Cribbing is thought to increase internal opiate release. Opiate release, in turn, causes a self-induced calming or tranquilizing effect that only reinforces the behavior. Cribbing tends to be associated with the lack of environmental stimulation and social structure that normally exist in free-ranging horses. A few professionals continue to feel that cribbing can be a learned behavior from other horses.
Cribbing is diagnosed by observation of the behavior, or by identifying missing u-shaped pieces on the uppermost wooden fence pole or rail. Horses that crib excessively may have worn top teeth and thickened neck muscles.
Since cribbing is associated with internal opiate release, the suggested treatment is to administer an opiate-blocking agent such as naloxone or nalmefane. These agents help block the cycle caused from opiate release. Increasing roughage and decreasing sweet feeds in the diet may also be beneficial because sweet feeds can cause the internal release of opiates. Other treatments include changing the horse’s environment by adding variety such as allowing access to pastures, providing horse-approved toys, and changing the affected horse’s companion(s). In some cases, it may be more realistic to do nothing and ignore the behavior unless the horse is losing weight or affected by colicky gas. In problem cases, surgery maybe considered as an option.
Cribbing collars may be used to prevent cribbing by placing adverse pressure and pain on the neck when it is flexed. This, however, is not a guaranteed preventative because some horses will crib despite the cribbing collar. If the horse is harming itself during cribbing, a cribbing muzzle may be applied. Ideally, the best preventative is to understand horses’ normal social behavior and environmental needs, and attempt to establish these as much as possible.
Pawing and Kicking: Pawing and sometimes kicking occur when a horse is bored or anticipating something such as food, water, or exercise. Pawing is sometimes associated with a desire to escape or with a diet lacking in roughage. Kicking can be the result of aggression towards another horse or because of frustration. Both problems are potentially dangerous to the horse and possibly to other animals and humans. In either case, the exact reason why the horse is pawing or kicking should be determined. Then the proper treatment such as counterconditioning (see the end of this discussion for details), more exercise, better socialization, a change in diet, and other suggestions found under stall walking can be implemented.
Pica: The term pica means consuming anything out of the ordinary for the horse. This may include sand, gravel, wood, and even manure (coprophagia). Consuming foreign material can cause colic, impactions, and injury to the stomach and intestinal tract. In certain cases, this may be an almost "ritualistic" behavior. Chewing wood is often a result of a lack of time spent grazing, especially during the winter months. It is also associated with consuming small amounts of long stem roughage (less than 1 lb of hay per 100 lbs of body weight) or consuming a pelleted diet. Coprophagia is considered a normal behavior in foals and is most common in the first month of life. If it occurs in adult animals, it is usually associated with a low protein, low roughage diet. It can also occur with dietary deficiencies.
With all of these problems, it is important to act quickly (with the exception of coprophagia in foals) before the problem becomes a habit. The key is identifying the reason the horse is consuming the abnormal material and then replacing it with something that is appropriate. This may mean feeding more hay, increasing the amount of protein in the diet, and adding a salt/mineral supplement. If available, allowing the horse more time to graze can often solve the problem. Exercise and preventing boredom with horse approved play toys are also great options if the problem does not seem to be associated with a lack of roughage.
Rejecting a Foal: Mares tend to reject their foal in three different ways:
To treat these problems, it is important to identify why the mare is rejecting the foal. Some mares that accept the foal but will not let it nurse, do so because of mastitis or pain associated with nursing or lack of nursing. If mastitis is the cause, it should be treated with frequent milkings and antibiotics. If infrequent nursing is the problem causing the udder to distend, try massaging the udder and warm water soaks.
Provide an area where the foal can safely and frequently nurse from the mare. This may involve cross-ties, bars, and barricades that allow the mare to see and smell the foal, but protect the foal from injury. Try and make the experience a positive one for both the foal and mare. Supervise and encourage frequent feedings for the first couple of days and reward the mare for good behavior with positive reinforcement. Making the stall area quiet and dark, along with tranquilization, can often help a mare that is afraid of the foal. If the mare is aggressive and wants to injure the foal, stocks and bars are essential, along with counterconditioning techniques for the mare. Things that stimulate the mare to lick the foal, such as rubbing the placenta on the nose of the mare and foal, can also be used. This is most important in the first few hours of life and will help establish the bond between mare and foal.
Self-inflicted Injuries: This is an uncommon behavior problem that can appear in sexually frustrated horses, in animals that do not socialize well into the herd, and as a compulsive disorder. It can also be the result of certain medical conditions. The most common areas for self-mutilation are the limbs, flanks, and chest. These are areas where the horse can access with the mouth and cause biting injuries. If this problem is associated with sexual frustration, castration and changing the horses the problem animal can associate with will often help. Many times, things such as increased exercise, diet changes (increased roughage and decreased grain), and medications (progestins, opiate blockers, anti-anxiety drugs) are beneficial.
Stall Walking, Circling, or Weaving: Horses that are confined, bored, claustrophobic, or separated from another horse may stall walk or circle. Horses that weave do so when they are restricted from moving because of being tied or from being in a very confined space. All these horses can spend valuable energy in wasted movements. They can even become overheated on warm summer days. Treatment for these problems can involve increased exercise, access to pasture, letting the horse see other horses, providing a companion for the horse, frequent feedings, and some medications. Simply untying or allowing more room for a horse that weaves will often solve the problem.
Trailering Problems: Problems encountered while trying to get a horse to enter, stand in, and leave a trailer are common. The potential for injury to the horse makes these problems more serious. Trailering problems should be addressed early in horse’s life. Loading problems can often be treated by using some or all of the following techniques:
Counterconditioning, Desensitization, and Reinforcement
: Counterconditioning is the replacement of undesirable behavior with an acceptable behavior. The acceptable behavior may simply be standing still, but it must interfere directly with the undesirable behavior. The acceptable behavior can be rewarded using positive reinforcement techniques. Counterconditioning may be useful for horses with anxieties, aggression, and other disorders. An example of counterconditioning is where a nervous or pawing horse is fed only when it is quiet and calm. Desensitization is one of the most commonly used techniques in behavior modification therapies. It consists of gradually exposing the horse to the event or object that causes the undesirable response. Desensitization is especially useful with anxieties, fears, and phobias, but is also very helpful in some types of aggression. Desensitization is often combined with other techniques such as positive reinforcement and counterconditioning. An example of desensitization coupled with counterconditioning is where a horse that is aggressive towards another horse is introduced gradually to that horse. Sometimes, this is done while both horses are separated by one and even two fences for protection. The horse is then fed only when it displays non-aggressive behavior. This is the process of altering the probability that a certain behavior will repeat itself. Reinforcement can be either negative or positive.Selected Reference:
•Aiello, BS: The Merck Veterinary Manual, 1998, Merck & Co., Inc.,
Whitehourse Station, NJ.