Horse Stable Vices and Domestication
What we horse owners refer to as stable vices (cribbing, wind sucking, and weaving), are also known as stereotypies, or frequent repetition of the same movement, gesture, posture, or sound. These repetitive behaviors have been recently described as “the disease of domestication,” and only develop in horses kept in domestic environments.
According to a 2021 article in “The Horse,”1 behaviors like cribbing and weaving are associated with structural changes in the brain itself.
Stereotypies
Horses aren’t the only animals where stereotypies occur. Stereotypies are seen in primates, birds, and carnivores. Up to 54% of elephants in zoos display stereotypical behaviors, and kenneled dogs display actions such as circling, pacing, whirling, jumping, wall bouncing, self-biting, compulsive staring, and constant barking.
Ten years ago, my family got a special private tour at the San Diego Zoo at Christmas. We were ushered into the tiger house, or I should say tiger holding area; and for one half hour I watched a female tiger pace the front of her cage. She was so full of anxiety that I became nauseous just feeling her angst. I can’t tell you how hard it was to resist the impulse to set her free. I will never go to another zoo again.
Researchers point out that these behaviors don’t have a real purpose. According to Emmanuela Dalla Costa, DVM, PhD, at the Department of Veterinary Medicine at the University of Milan, Italy, these stereotypies aren’t caused by boredom and aren’t habits horses pick up from other horses.
“Horses perform stereotypies such as cribbing and weaving when their environment is suboptimal.” 2
Stereotypies offer the horse a degree of perceived control that is predictable. The repetition produces a beneficial neural feedback loop.
Understanding the brain component
Near the center of the brain is a structure known as the striatum. The upper part is the dorsal striatum and the lower part is the ventral striatum.
The dorsal striatum is involved in goal achievement. The ventral striatum focuses on motivation: the concept of getting a reward. In horses that don’t exhibit stable vices, the two parts of the striatum work together.
The striatum is rich in the neurotransmitter dopamine, which is activated when one or both parts of the striatum are functioning. However, horses that develop stereotypy behaviors, may get a dopamine boost to the ventral striatum (reward motivation) and reduced dopamine from the dorsal striatum (goal oriented).
The result, according to researchers, is a strong drive for meaningless activity.
Causes of stereotypy formation
Stereotypy formation is most commonly found in thoroughbreds and warmbloods, and is linked to management factors. Behaviorists point out that one of the early contributors is a stressful weaning experience.
Other factors include:
- Lack of forage or time spent eating
- Not being bedded on straw
- Limited social contact with other horses
- Not enough free time and movement outside of the stable in turnout
Behavioral disorders under saddle
A study published in 20093 looked at 76 French warmblood geldings, individually stalled, no turnout, ridden for one hour a day. Researchers found that the type of work a horse did was a significant factor in the development of stereotypies. Dressage horses presented the highest incidence and most serious of the stereotypies. Vaulting horses exhibited the fewest and mildest stereotypies.
Out of the 76 horses, an astounding 65 showed some evidence of stereotypical behavior. The authors of the study suggested that potential interpersonal conflict between riders and the horses could explain this pattern.
How to stop cribbing
Researchers and behaviorists agree that devices and methods to reduce cribbing don’t address the underlying cause of the behavior and thus compromise equine welfare. Louise Nicholls of the British Horse Society puts it this way:
“The goal is not to force them to stop, but to find ways to make them need it less.” 4
Environmental and social enrichment
As we all know, horses are social animals. In the wild or in a home herd, horses form pair bonds that can last a lifetime. Mutual grooming is an important social behavior and even lowers a horse’s heart rate.
According to research, both long-term and short-term social isolation can impact horse welfare in a negative way. Horses are by nature highly motivated to seek social interaction.5
Housing horses in a way that allows visual contact appears to reduce the risk of stereotypical behaviors.
Keeping horses in groups is especially important for juvenile horses. Juveniles will be less aggressive and have better social skills if they are kept in group turnout and housing compared to individual stalls.
We can’t forget that the basic motivations and behaviors of horses have remained relatively unaltered by the domestication process. Horses whether in the wild or domesticated need social stimuli, social interaction, and companionship.
Ulcers don’t cause stereotypies
Interestingly, ulcers are the result of the behavior, not the cause of it. This is hugely important. Treating a cribbing horse for ulcers will help the ulcers but not the cause of the cribbing.
With this new understanding of stereotypies, we now realize that horses don’t teach each other cribbing or weaving. Those behaviors are a direct response to frustration and stress.
What we can do to reduce social isolation
Horses need to see and touch one another. We build strong stall walls to protect horses, and yet this creates social isolation, frustration and stress for many of them. We turn horses out in individual paddocks for their protection, but unless the paddocks are side by side and in touching distance for the horses, this just adds to isolation. Just like humans, horses need companionship.
There’s a scene in the movie “Seabiscuit”, when the trainer, Tom Smith, tries to figure out how to reduce Seabiscuit’s anxiety and rage. After trying to bring him a goat, he brought a calm palomino mare, who ends up being the antidote to Seabiscuit’s frustration. All he needed was an equine friend.
Horses need to eat 20 hours a day. I believe many horse owners and trainers have made great strides in making sure our horses are eating constantly. But the horses still need time in turnout, if possible with another horse. They need to groom another horse or be near enough to touch another horse. This physical contact is endemic to their nature and biology.
We also need to think about our role as trainers, in terms of the conflict we may bring to a training session. The study in France (referenced above) highlighted the interpersonal trainer horse conflict and its effect on stereotypy and thus behavior.
Riding in groups
Riding our horses in groups is one idea to try to help reduce isolation from confinement (I have no scientific data to confirm, but it’s an idea). Trail riding in groups and working in the ring with other horses may be a good step in reducing equine frustration.
We have the responsibility to work with the horse’s nature, biology, and innate needs. Reducing the need for horses to weave, crib, and wind suck is an achievable goal.
References:
1 – https://thehorse.com/1105995/vices-in-horses-are-diseases-of-domestication/
2 – https://thehorse.com/1105995/vices-in-horses-are-diseases-of-domestication/
3 – https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0007625
4 – https://iaabcjournal.org/environmental-enrichment-companionship/
5 – https://www.sciencedirect.com/science/article/abs/pii/S0168159111001249
