Equine “vices” are annoying. Can they also affect soundness or other aspects of performance? Here’s what we learned.
By Heather Smith Thomas
Reprinted from the July/August 2020 issue of USDF Connection magazine.
Domestic horses may exhibit behaviors not seen in free-roaming horses. The stress of confinement, isolation from other horses, or both can lead to repetitive actions known as stereotypies. Also referred to as vices, such behaviors include cribbing, weaving, stall-walking, stall-kicking, and self-biting. Once established, a stereotypic behavior can become a need in itself, and the horse continues it.
We wondered whether stereotypic behaviors affect horses’ ability to stay sound and to perform successfully in dressage. To find out, we talked to top veterinary researchers as well as to dressage professionals who have worked with such horses. Here’s what they told us.
Physical Implications
“If dressage horses exhibit weaving or box [stall] walking, the additional activity and loading in the limbs could potentially increase the risk of musculoskeletal injury, especially as they tend to favor walking in one direction over another,” says Dr. Jane Williams of Hartpury College in England, who with Dr. Hayley Randle of Charles Sturt University in Australia recently published a review evaluating the impact of stereotypies on performance. Williams adds, however, that “there is very little research to support this.”
One US-based expert who frequently fields questions related to equine stereotypies is the noted researcher Dr. Sue McDonnell, founding head of the Equine Behavior Program at the University of Pennsylvania School of Veterinary Medicine’s New Bolton Center in Kennett Square, Pennsylvania. McDonnell speculates that the repetitive actions associated with stereotypies could potentially be at odds with one’s training objectives. Cribbers, for instance, tend to have overly developed “under neck” muscles, which could alter a horse’s topline, its balance, and its ability to go on the bit. A weaver or stall-walker may be harder to keep weight on as a result of the extra calorie burn, and its movements may produce fatigue or muscle tightness. If a horse always walks or weaves in the same direction, or if its motion puts more stress on one limb (or one side of the limb) than the other, there could be an increased risk of injury, McDonnell says.
Another physical issue associated with stereotypies is ulcers.
“Many of these behaviors, especially cribbing, are associated with minor physical ailments, like gastric ulcers,” McDonnell says. “People argue about which comes first, the cribbing or the ulcers.” She recommends checking any horse with vices for ulcers. If ulcers are brought under control, the stereotypic behavior may lessen, she says.
Stereotypies and Learning Differences
Because stereotypies manifest physically, we tend to think of their effects in those terms. But according to Williams, the brains of horses with stereotypies may actually be different from those of their “normal” peers.
Horses with stereotypies may learn differently than horses that do not exhibit such behaviors, Williams says: “Some studies suggest that stereotypic horses learn associations more quickly and stronger, and take longer to ‘unlearn’ them, 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. For the dressage horse, this could mean these horses learn cues for the lateral and advanced movements quicker, but if the rider confuses the signals, the wrong response will be learned just as quickly.”
As a result, such horses may be somewhat better suited to experienced riders and trainers, who are less apt than novices to use incorrect or inconsistent aids, Williams says. Paired with the right rider/trainer, the stereotypic horse might even progress more quickly than its “normal” counterpart, she surmises.
That ability to make associations between behaviors and outcomes can work for or against us, Williams notes: “The learning and behavior studies we’ve done over the years make it clear that any sort of attention [paid to a horse when it exhibits a given behavior] reinforces the behavior. The smart horses learn that if they make a ruckus, someone will come and give them attention. Whether it’s yelling at them or feeding them, it drives that behavior as reinforcement.” In other words, when you scold your horse for cribbing or for pawing at feeding time, you may think you’re discouraging an unwanted behavior—but from your horse’s point of view, you’re reinforcing him.
Life with Stereotypies
Elverson, Pennsylvania,-based dressage trainer Angelia Bean currently has a weaver in her barn, and over the years she’s dealt with cribbers, other weavers, and stall-kickers.
“People worry about performance, but I feel stereotypic behavior is a bigger problem in the barn than under saddle,” Bean says. “It generally doesn’t affect a horse’s dressage career, though a weaver or stall-walker may have days when their backs, shoulders, and legs are tight. Regarding cribbers, I have two I’m working with right now, and I’ve never noticed that it had any effect on their dressage performance.”
Bean wondered whether the cribbing action puts extra stress on a horse’s back and hocks, and posed the question to her veterinarian. “The vet didn’t seem to think it would, because the horse doesn’t hold that position very long,” she says.
The one area of the horse’s body that cribbing seems to affect, in Bean’s experience, is the poll.
“I have found cribbers to be more sensitive at the poll,” she says, “so you have to be very particular about bridle fit. The anatomical bridles help a lot.”
One particularly dedicated cribber, owned by a student of Bean’s, even cribbed while turned out and while wearing a cribbing collar (most cribbers crib only while indoors). The collar succeeded only in making the horse’s poll sore, “so we quit using it,” Bean says. The vice didn’t stop the horse and his adult-amateur owner/rider from progressing to Third Level, she notes.
The current weaver in Bean’s barn is triggered when he feels claustrophobic and anxious, meaning that he’s worse when he’s in a windowless stall with a full door so that he can’t put his head out.
“His anxiety seems a lot worse than a horse that’s just rhythmically weaving back and forth,” says Bean. “A weaver I had previously moved back and forth in an ‘autistic’ way, but he progressed through the dressage levels just fine. He was a really bad weaver; he even did it outside, not just in his stall.”
Although managing a cribber or a weaver has its challenges—“cribbers are hard on the facilities, and weavers dig holes in their stalls”—Bean has found that “stall-kickers are much harder on their bodies than the cribbers and weavers, because the kickers can injure their feet and legs, and their hocks and SI [sacroiliac] joints get pretty sore.”
When she helps a client shop for a horse, Bean takes a pragmatic approach to the subject of vices.
“As a trainer, if a horse has a solid mind and his temperament is appropriate, I will overlook stereotypic behavior like cribbing or weaving. But if a horse is a little difficult in any way, it becomes the straw that broke the camel’s back. It’s one more challenge we don’t need. If the owner gets discouraged and decides to move on to another horse, there is a potential resale problem,” she says, noting that “some people will not buy a cribber.”
“That being said,” Bean concludes, “I’ll take a cribber or a weaver over a strong-willed, rude horse or [one with] a dirty spook any day. There’s no perfect horse; you try to pick what is most important to this particular horse-rider combination, as part of the big picture.”
“I think cribbing can be attributed to many things, some of which may be serious,” says Merrie Velden, a dressage pro in Fresno, California. “I owned one cribber that had a malfunction in his small intestine, and for him cribbing was probably a way to alleviate pain.” Cribbing, she points out, has been shown to release endorphins, “which puts the horse in a happy place.” Sadly, that horse succumbed to his intestinal defect before he reached the age of five.
Some horses, Velden believes, crib simply because it makes them feel good. “The cribber I have now just cribs for pleasure after eating grain,” she says. “We know this mare does not have ulcers because we scoped her. I think she just craves the endorphins.”
Concerned that nonstop cribbing would develop the mare’s “under neck” muscle to the detriment of her dressage training, and unwilling to use a cribbing collar “because they cause pain,” Velden tried to crib-proof the mare’s environment. “We had to take down her feeder, remove the waterer, and anything else she could reach that was high so she can’t develop that neck muscle. She still found a way to crib on the side of the stall door, but she has to lower her head and neck to do it. We feed her grain in a little pan and her hay on the floor, and her water is in a plastic tub that is very low so she can’t crib on that.” Hot wire around the top rail of her paddock discourages the mare from cribbing on that surface. The result: “She goes nicely and softly on the bit, and I don’t feel the cribbing is a problem, but we’ve taken every humane action to prevent it.”
Cribbing activity can cause wear on a horse’s top incisor teeth, but Velden says the issue hasn’t affected her mare.
“If you look at my mare’s teeth, one is a little shorter because she has to crib low and at an angle,” Velden says. “I am not worried about it because this doesn’t interfere with her eating or riding. She’s eight now and has learned to go on the bit on the snaffle, and keeps a very soft, lovely frame. Her bottom neck muscles are normal and beautiful, and she’s the first horse I got [a score of] 80% on, in Training Level. That doesn’t happen on a horse with an abnormal bottom neck muscle.”
Velden also has experience dealing with a weaver—a mare that “could pick up speed and weave incessantly,” she says. “This mare would stand and weave very fast, with her head barely clearing the stall wall.”
“There is a neurotic component to this behavior,” says Velden. “Horses that weave are not happy horses. When we took this horse to her first show, she weaved continuously and made holes in the stall. We had to take her out of her stall for three hours and just hold her in the arena so she wouldn’t go nuts. At a three-day show, it took until the third day to finally be able to show her without her losing it.”
In Velden’s experience, “Thoroughbreds lead the list as weavers, maybe because they are confined and very hyper [in the racetrack environment]. It’s a bit like lions in a zoo. Caged animals pace and develop repetitive behaviors. I know of horses that have become so broken-down and unsound from weaving that you lose them to those issues,” she says.
To curtail the mare’s weaving, Velden analyzed the behavior pattern. She saw that “a weaver wants to weave facing front, by the door where they’d go out—and since they can’t go out, they weave.” She placed old tires in the front of the stall so that the mare couldn’t stand there, and “because they don’t want to weave at the back of the stall,” the weaving largely stopped, she says.
The effort, Velden says, was worth it: “That mare was actually one of my best riding horses, and easiest to train, once she trusted me. I have her four-year-old and five-year-old sons right now, and her five-year-old is my all-time favorite horse. He is a little high-strung like his mother and a little ‘cracker’ sometimes, but he doesn’t weave.”
In the end, “we don’t like the sound of a cribber, or the look of it,” Velden says, “but weaving bothers me a lot more.”
Address the Cause, Not the Symptom
Although it may be encouraging to learn that a horse with a stereotypy can succeed in dressage, most of us would just as soon eliminate the behavior, which can range from irritating to downright distressing. McDonnell urges a holistic approach rather than merely trying to suppress the action.
“There is some sort of stress or discomfort that led to these behaviors,” she says. “Don’t add stress by yelling at the horse or punishing the behavior. The humane thing is to figure out why the horse is doing the stereotypic behavior and try to alleviate or resolve that reason, rather than try to thwart the behavior.”
McDonnell acknowledges that “vices”—like those that we humans engage in—can prove difficult to break. A stereotypic behavior “may become a reinforced habit because endorphins are released as the horse exerts or gets worked up,” she says. But she offers a note of comfort to owners of such horses, who tend to fret about their animals’ worrisome repetitive actions.
“It can be helpful to get a 24-hour video of the horse, because often the horse is only doing it when people are there. It can be a relief for the owner or trainer to know the behavior is simply related to feeding time or when someone is in the barn,” she says
Do Stereotypies Have a Genetic Component?
California-based FEI-level dressage trainer and competitor Merrie Velden is convinced that genetics plays a role in the development of equine stereotypies.
“A famous sire in Germany was a cribber, and he produced cribbers,” she says. “There seems to be a genetic factor. People wonder if behavior is due to nature or nurture, but I’ve raised a lot of embryo [transfer] babies and had the mother, and the babies have some of the behavior quirks of Mom, even when they never knew her.”
Example: A mare Velden has bred using embryo transfer has the unique habit of rolling on one side, then turning over by sitting on her haunches like a dog and walking her front legs over to the other side. “Her son does the same thing, and she never knew her son; he was raised by a different mare.”
Because stress, confinement, or both seem to trigger the emergence of stereotypic behavior, you could own or even breed a horse with a genetic predisposition to stereotypies and never know it—if, say, he lives outside all his life.
The possibility of a genetic component could be comforting to owners of cribbers, as well as to those whose horses are stabled with those cribbers.
“Some people don’t want a cribber in their barn because they think it will teach the other horses to crib,” says Velden, “but I think this is a fallacy. I’ve had cribbers, and no other horses in the barn around them cribbed.”
Heather Smith Thomas has raised and trained horses for 50 years, written more than 12,000 stories and articles, and published 24 books. Her recent books include Storey’s Guide to Raising Horses, Storey’s Guide to Training Horses, Understanding Equine Hoof Care, and Horse Tales: True Stories from an Idaho Ranch.
