Page 49 - New Mexico Summer 2022

PREVENTION AND TREATMENT
The best remedy for stereotypic behaviors
is preventative management, so a horse never has reason to learn to do them. Allowing horses more room for natural activities, feeding more roughage and less grain, or feeding smaller amounts more often so the horse spends more time eating and less time inactive, can help. Pasture time is best, but if this is impossible, devise ways to increase eating time, and give him a larger paddock or more time out of his stall. Provide ways for horses to be near other horses. Visual contact between stalls will often cut down on abnormal behavior. A companion animal may help some horses feel less isolated.
horses from weaving or stall walking but they usually start it again if they are again confined. Change in environment generally won’t stop
a cribber; he will find something to crib on out in the pasture. Treatment with narcotic blocking drugs that neutralize substances like endorphins is often effective, but the horse generally ceases his stereotypic behavior only as long as the drugs are in effect. The benefit is only temporary, and not a cure.
Dr. Sue McDonnell (University of Pennsylvania School of Veterinary Medicine Department
of Clinical Studies, New Bolton Center) is a leading authority on equine physiology, behavior and welfare. She has studied stereotypies in
EQUINE HEALTH
Dr. Jane Williams (Head of Research, Department of Animal and Agriculture, Hartpury University in England) and Dr. Hayley Randle (Associate Professor in Equine Science, Charles Stuart University in Australia) produced a review evaluating the impact of stereotypies on horses’ performance a few years ago. Williams says that from her perspective, if confined horses exhibit weaving or box walking, the additional activity and loading in the limbs could potentially increase their risk of musculoskeletal injury.
“They tend to favor walking in one direction over another, but there is very little research to support this. Cribbing also has the potential to cause incisor teeth wear over time and this could affect the horse’s dentition. Probably the most interesting aspect from the literature related
to horses that exhibit stereotypies linked to performance is the apparent differences in how they learn,” says William.
“There are studies suggesting stereotypic horses learn associations more quickly and stronger, and take longer to ‘unlearn’ it, than non-stereotypic horses. This is great if the horse is taught well, but not so good if they ‘learn’ the incorrect responses to cues.”
SELF-MUTILATION SYNDROME
One of the most detrimental stereotypies
in horses is self-mutilation. The horse bites at himself, often spinning around and grabbing his flanks. He may pin his ears back, gesture toward his flank, then suddenly lunge and squeal as he circles and nips at himself. Or he may make biting movements aimed at his legs, flanks or tail without actually making contact. Some horses take chunks of skin off with their teeth. Some make grunting or barking noises while nipping themselves.
This destructive activity occurs most often
in male horses, especially confined stallions, perhaps because they are kept isolated from other horses. Early research on this problem was done at Tufts University, led by Dr. Nicholas Dodman in the 1980’s while doing research on cribbing. Self-mutilation in horses may have a genetic tendency but does not occur in horses under natural conditions; it seems to be brought on by stress and then the habitual behavior becomes addictive due to the involvement of body-produced opioids/endorphins.
Young horses are more apt to develop stereotypies when brought into an unnatural environment than are older horses. Often a youngster that starts a compulsive behavior continues it throughout life, even if his circumstances change, since it has already become ingrained. Older horses are less apt to develop these behaviors when put into
a confined situation, if they had a normal environment during their growing up years.
Any long-term confinement for a young horse presents higher risk for developing stereotypies. The best solution is to give young horses a more natural environment at pasture or in large paddocks, and with groups of their peers, rather than confined in stalls.
Treatment is generally not nearly as successful as prevention. Castration helps alleviate self-mutilation behavior in some stallions, but not others. Change in stabling or allowing a horse to be at pasture with herdmates, rather than confined in a stall or isolated in a separate paddock, may keep some
horses and is often asked about these problems. Horses in many sports and disciplines are usually confined in stalls, which often leads to stereotypic behavior. Riders and trainers often wonder if these repetitive actions might have an adverse impact
on performance. Overly-developed neck muscles in a cribber, for instance, might affect the horse’s balance and ability to get on the bit. The repetitive actions of a weaver or stall-walker might make a horse tired or result in tight muscles.
“Yes, these behaviors can impact performance. It stands to reason that the horse is using energy for something else, and there is some sort of stress or discomfort
that led to these behaviors. Then it becomes a learned, reinforced habit because many
of these behaviors release endorphins as the horse exerts or gets worked up. Current thinking is that the only humane thing to do is to try to figure out why the horse is doing the stereotypic behavior and try to alleviate and resolve that reason, rather than trying to thwart the behavior,” says McDonnell.
One of the most detrimental stereotypies in horses is self-mutilation when the horse bites at himself, often spinning around and grabbing his flanks.
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