Progress in Equine Pain Recognition

Equine Pain, horse pain, grimaces score, equineguelph, grimace pain scale

Equine Pain, horse pain, grimaces score, equineguelph, grimace pain scale

By Jackie Bellamy-Zions  

Hiding pain is one of the top survival skills of the horse. An important part of horse ownership is learning to recognize the signs a horse may be in discomfort rather than dismissing certain subtle cues as just bad behaviour. Earlier this year, Dr. Brianne Henderson gave a well-received lecture to a room full of horse owners in Hillsburgh, ON. The attendees were interested in ensuring the welfare of their equine companions by honing their skills for detecting pain.

There has been increased awareness of pain recognition and management in small animals, and this science is also gaining more acknowledgement in the world of horses as well. The Facial Grimaces Score used originally to identify pain in rodents and rabbits has been incorporated into a Horse Grimace Pain Scale” for equines as well. It uses ear position and tightening of the muscles around the eyes and mouth to come up with a score (0 - no pain; 1 – moderate pain; 2 – obvious pain). Everyone wants to be greeted by a bright-eyed, soft and relaxed face. The horse is telling you something hurts when he avoids looking at you, appears despondent, clenches his jaw, flattens ears back and/or squints his eyes. 

Equine Pain, horse pain, grimaces score, equineguelph, grimace pain scale

Citation: Dalla Costa E, Minero M, Lebelt D, Stucke D, Canali E, Leach MC (2014) Development of the Horse Grimace Scale (HGS) as a Pain Assessment Tool in Horses Undergoing Routine Castration. PLoS ONE 9(3): e92281. doi:10.1371/journal.pone.0092281

Dr. Henderson went on to briefly explain pain scales used by veterinarians that focus on physiological parameters and behaviour patterns. One included the Composite Pain Scale (CPS) which looks at the change in frequency of normal behaviour patterns such as eating, the presence of pain-related behaviours such as kicking at the abdomen, and physiological parameters such as elevated vitals. There is a long list of signs that are scored from 0 to 3. Some of these indicators, including vitals, can also be assessed using a quick 16-point health check poster developed by Equine Guelph. The poster or handy new Horse Health Tracker app are invaluable tools for horse owners to provide important health data to their veterinarian.

Henderson rolled through a barrage of images asking the audience to denote which ones depicted animals in pain. By stance, facial cues, and action, the savvy auditors were hitting the mark and also picked up on the fact that circumstance plays a role. How many people have had the phone call of alarm when a passerby sees a horse flat out in the field, when it was actually just napping in the sun? Flehmen is another response that can be circumstantial. It can occur due to an interesting smell or taste sensation, but it can also be a moderate pain response displaying nostril and mouth tension. The stallion curling his upper lip testing for pheromones when a mare passes by is a different context than the horse that didn’t finish his feed, and is stretched out with his poll low and is showing the flehmen response.

Equine Pain, horse pain, grimaces score, equineguelph, grimace pain scale

The flehmen response can occur due to an interesting smell or taste, but it can be a moderate pain response displaying nostril and mouth tension. Photo: ©Canstockphoto/Virgonira

Subtle changes require your attention such as a horse at the back of its stall with a half-eaten breakfast, when it normally stands at the door waiting to go out after licking the feed tub clean. Catching a potential colic at this early stage could result in a huge cost savings as well as avoid what could turn into a very painful experience for the horse. The performance horse that suddenly starts refusing to accomplish tasks that it once found easy requires a careful evaluation, as early signs of lameness rather than misbehaving could be the culprit. As the owner of a stoic animal accustomed to hiding pain, the horse person must be on the lookout for atypical behaviour such as a horse that begins to segregate itself from the herd or suddenly displays a less tolerant behaviour with its paddock mates. 

Equine Pain, horse pain, grimaces score, equineguelph, grimace pain scale

A horse that stands at the back of his stall and ignores his feed should be carefully monitored. A potential colic caught at an early stage could save your horse from a painful experience and save on your vet bill. Photo: Belinda-Hankins-Miller/Wikimedia Commons

When variations in behaviour occur, a step back may be required to figure out if it is you or the horse that has changed. “If I’ve had a bad day at the office and not taken the time to decompress, my horse will not come to the gate for me,” Henderson explains. “Similarly, I know if he doesn’t come to the gate under normal circumstances, there is something wrong because he typically loves his job.”   

Equine Pain, horse pain, grimaces score, equineguelph, grimace pain scale

Look for clues behind atypical behaviour, such as when a horse suddenly displays a less tolerant behaviour with its paddock mates. Photo: Coen Dijkman/Flickr 

Grooming is the next interaction where paying close attention will tell you much about your horse’s health. Rather than quickly dusting off the saddle area and jumping on to ride, take the time to run your hands over the horse’s whole body, especially the back and legs, before and after work, checking for any heat, swelling or reactions that can be early indicators something is not quite right.

Obvious pain requires a veterinary examination. When a horse comes in from the paddock hopping lame, it can often be hard to tell if it is an abscess requiring a simple poultice, or a fracture requiring much more intensive treatment and stabilization. When acute pain is obvious, don’t guess or delay - call a veterinarian. 

For less obvious lameness, your veterinarian has been trained to assess the severity on a scale from one to five. Early intervention increases the chances of a good outcome and can prevent matters from escalating into a much worse injury. The veterinarian will check the horse in both walk and trot, on straight lines and turns. “A lameness that is visible at the walk is automatically going to be at least a three if not higher,” says Henderson. After a thorough exam, a rehabilitation plan can be made.

Chronic pain will impact the horse’s ability to heal and their quality of life. “It is an old way of thinking to want a horse to be a bit sore in the healing process to prevent it from box-walking,” says Henderson. “Our ability to control pain both every day and certainly in the medical environment is becoming more and more recognized as mandatory.” Once the horse is controlled in his pain, he can move better and heal faster, and therefore not lose as much muscle quality during the healing period. Modern treatment methods can also help avoid the effects of stomach ulcers and sourness that often accompany chronic pain. Choosing the right pain control method or treatment is another conversation to have with your veterinarian as there are many options available, and extended use of Phenylbutazone can have negative effects on a horse’s stomach.

In addition to being on the lookout for signs of pain, a dutiful horse owner is always employing prevention practices, such as applying a poultice and wrapping their horse’s legs to stem swelling after a hard workout, and give the horse time to recover. Similarly, we take care of ourselves with rest after a workout, a hearty meal to replace nutrients, and perhaps a hot bath. Our horses count on us, their primary caretakers, to be diligent and attentive in both prevention and early detection of pain.

Reprinted with the kind permission of Equine Guelph.