Horses’ body language and habits can tell you a lot about their pain levels, moods, and motivations.
Observe your horse’s habits and body language to determine whether he’s in pain
Debra Sellon, DVM, PhD, Dipl. ACVIM, often finds herself trying to reverse-engineer her impressions of equine pain. Her students ask her how she knows a horse is in pain, and she stops to consider what she saw in a horse’s body language. And still, she has questions.
“I’ve been a veterinarian now for 40 years, and I’m more uncertain than ever about what I’m seeing,” says Sellon, a professor of equine medicine in Washington State University’s College of Veterinary Medicine, in Pullman.
Over her career she’s noticed a lot of variety in professional assessments on equine pain. “Why would we look at the same patient—both very experienced people—and have totally different opinions as to how painful they were?” she asks.
Sellon’s recent research suggests one’s perception of how much pain a horse is experiencing and whether the horse needs pain relief has a lot to do with who you are. In her survey-based study she found:
Horse owners providing high pain ratings were more likely to have fewer than 10 horses and to not have a college degree.
Veterinarians providing high pain ratings were more likely to be employed in a mixed animal practice and to lack board certification in a veterinary specialty.
Veterinarians providing low pain ratings were more likely to be male. (Sellon noted the gender differences might have more to do with graduation date, as the veterinary field trends more female).
She recalls sharing her research during a continuing education event. One audience member, she says, was shocked by the variety in pain scores for common equine ailments. He wondered whether he needed to rethink his interpretation of equine pain behavior. But that type of questioning can be good, she says—it means you’re paying attention.
“At least you’re thinking about it, and you’re more likely to do something,” Sellon says. “I tend to err on the side of thinking they can be painful and helping this pain would be good.”
The Question of Social License
“I think they’re continually speaking to us,” says Amy McLean, PhD, assistant professor of teaching in equine science at the University of California, Davis. “Are we actually listening to them?”
Much of the research into equine pain involves a concern about our social license to continue competing and using horses, she says. Injuries and deaths create a negative perception of the equine industry, especially when the general public watches events such as horse racing’s Triple Crown. There’s social pressure to question whether we’re doing right by horses, she adds.
“If we can start to recognize those signs of pain and distress early on, I think then that just helps the outcome,” McLean says. “It helps the whole industry.”
If horses are talking to us about pain, the thinking goes, we better listen.
The Tools to Help Us Understand
Body language is a horse’s primary communication method. Pay attention, and you’ll find horses telling you about their pain levels, moods, and motivations.
Ethograms and grimace scales are tools scientists have developed to help researchers and practitioners understand animals. An ethogram is a list of behaviors, whereas a grimace scale is a way to assess and score facial expression changes. If time is of the essence, you’ll want to learn the grimace scale.
In a 2014 study where researchers developed the horse grimace scale (HGS) to evaluate castration pain, they noted time is one advantage the scale offers over ethograms, because you can observe a horse’s expression with little more than a glance, whereas behavior must be observed over time.
The HGS details six facial action units (FAUs) that include stiffly backward ears; orbital tightening (eyes closing partially or fully); tension above the eye area; prominent strained chewing muscles; mouth strained and pronounced chin; and strained nostrils and flattening of the profile.
“Horses are social animals and, therefore, have a developed communication,” explains Sabrina Briefer Freymond, DVM, PhD, a researcher at the Agroscope Swiss National Stud and agricultural research center, in Avenches.
In addition to body language, your horse’s vocalization offers information. Briefer Freymond’s collaborators, for example, have examined whether horses communicate their emotions when they whinny. “This study showed that horses had different intonations when they whinnied in positive or negative situations,” she says.
Horses whinny in lower tones to horses (and people) they know, while a louder whinny or neigh is often a distress sound, explains McLean.
Upcoming Research
Humans already associate writing and symbols with communication. Could horses? Finding the answer to this question is on Briefer Freymond’s to-do list.
“We are currently working on whether horses can communicate their choice by associating a symbol with a consequence for their well-being,” she says, citing a previous study that showed horses could communicate through symbols whether they wanted to wear a blanket.
Other researchers are sniffing out questions of odor. Agnieszka Sabiniewicz, PhD, is a lifelong horse person who works as a researcher in Smell and Taste Clinics at University Hospital Carl Gustav Carus, in Dresden, Germany. Her research has demonstrated that horses can recognize human fear and happiness based on olfactory cues.
“Putting it simply, this is something that every horse person would confirm without studies—horses have a great ability to read human emotions,” Sabiniewicz says, “But what we additionally show here is that human odor is enough for them to understand what is going on.”
What’s more is humans might share that ability. Sabiniewicz’s research found “a fascinating novelty” where humans distinguished a horse’s fear or lack thereof only by sniffing pieces of fleece material that had been placed under tack from scared and relaxed horses.
“We are very excited about this finding, but it needs to be further investigated and replicated because of some methodological difficulties,” Sabiniewicz says. “For example, horses cannot simply declare that they feel stressed at the moment.”
What to Watch for, Head to Foot
The following expressions or behaviors appear on the horse grimace scale and a composite ethogram used in the development of it. Some of the behaviors are scored according to severity, while others are scored based on frequency or timing. Equine facial expressions are generally easier to evaluate from the side (in profile). Low scores mean less evidence of pain, while higher scores mean more.
Head, neck, and face You’re watching for head movements (up and down or side to side), such as looking at the flanks or lip curling. This is a time-based behavior, with one to two repetitions in five minutes being a low score and more than five repetitions being a high score. Also watch for a horse that’s carrying his head low, “below the horizontal.”
Ears Held stiffly or turned backward. The distance between the tips might appear wider than the baseline.
Eyes The grimace scale considers two factors related to eyes. If eyes are partially to fully closed, that’s a score of 1 or 2. Tension (muscle contraction) above the eye area makes the underlying bone structures more obvious. A clearly visible temporal crest bone represents a higher pain score. If you’re looking at the horse from the side, that’s the bone that goes diagonally upward from the corner of the horse’s eye.
Face Strained chewing muscles. If it looks like your horse is chewing but he’s not, score according to the HGS, with obvious chewing muscles receiving a high score.
Chin The mouth is strained and the upper lip is drawn back, with the lower lip giving the appearance of a pronounced chin. A very obvious “chin” gets a higher HGS score.
Nostrils Nostrils are strained, with the nose profile flattening and lips elongating. It’s scored on the HGS based on severity.
Body or posture Look for balance and weight distribution. Balanced standing with even weight distribution gets a low score, with scores increasing if the horse is shifting weight, not bearing weight on one leg, has muscle tremors, looks like he’s trying to pee, or is lying down. Legs that are stretched out, camped under, or dangling are also common indicators of pain.
Legs and feet You’re looking for a horse that’s standing quietly without kicking at the abdomen or pawing. Occasional kicking or pawing of fewer than one to two times in a five-minute period gets a low score, with excessive kicking or pawing (more than five times in five minutes) getting a high score. A horse kicking at his belly and attempting to lie down also earns a high score.
Appetite If a horse is readily eating, that’s a 0. Hesitation to eat is a low score, while a horse that doesn’t eat or show interest in hay is a high score.
Sweating Damp to the touch is a low score, while beads of sweat running off the animal is a high score. Wet to the touch with visible beads of sweat is a middle score.
Movement You’re looking for a horse that’s relaxed or quiet. Moving less or more than normal is a low score, with reluctance and refusal to move or “uncontrollable forward movement” increasing scores.
Interaction How does the horse respond to auditory stimulus (i.e., a person clicking their tongue)? Paying attention gets a low score, an exaggerated response gets middle scores, and stupor or nonreaction gets the highest scores. Also score defensiveness or resistance to touch, with no avoidance or defense reaction getting a 0.
Take-Home Message
Researchers stress that horses are individuals. Nobody wants you to panic over incidental behavior that might have a more immediate cause than an underlying ailment. Flies, for example, might cause a horse to appear very agitated. “Horses communicate with each other mainly through nonverbal communication,” says Briefer Freymond. “It is therefore very important for us to know their behavior in order to interact with them adequately.” The best way to understand a horse’s message is to observe them, she adds, remembering that each horse is different and some express their emotions less—and, therefore, are more difficult to read—than others.
