Pain in Horses: Types, Prevention, Management, and More

Nobody wants a horse to suffer or be in pain. But before pain can be effectively treated, it first must be detected – and that’s not always as easy as you might think. Yes, a horse that is lame or nipping at his belly is clearly in discomfort, but horses often hide other types of discomfort.

Dr. Bri Henderson an equine sports medicine veterinarian, based out of Mono, Ontario, with Ferguson Equine Veterinary Services, pointed out that “Horses are a prey species – they are preprogrammed to hide weakness and pain from potential predators. They are by nature stoic, and often the subtle cues of pain are missed in the daily hustle and bustle.”

Types

Pain can be classified into two general types: somatic, usually associated with bones, ligaments and tendons or injuries to the skin; and visceral, associated with the internal organs and the digestive tract. Somatic pain tends to be more localized, which can make it easier to figure out the source, while visceral pain can be apparent over a larger area of the body, so that the actual source of the injury is not as easy to identify.

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Recognizing it

What can a horse owner do to make sure the horse’s pain doesn’t get missed? As an avid endurance and dressage rider, Dr. Henderson knows the importance of careful observation. Since horses can’t tell us if they are hurting, knowing their normal behaviours and being alert for changes will help identify potential pain. Some things Dr. Henderson recommends watching for:

Change in appetite: Did your horse eat her breakfast? Is she drinking normally? While a change in intake could be a sign of digestive problems, horses experiencing discomfort anywhere in their bodies will often stop or decrease eating and drinking. You may also notice the lack of manure or see abnormal manure.

Avoiding work: If your horse normally comes to the front of the stall or the pasture gate when you arrive, it may be a sign that he’s in discomfort if he instead retreats to the back of the stall or stays in a far corner of the pasture. Resisting being tacked up can be another sign of pain.

Resisting specific movements while being exercised: If your horse suddenly or gradually begins refusing to turn left or right, for example, or starts refusing jumps when he’s previously been an eager jumper, this could be a sign of discomfort. If the problem is in his back or hindquarters, he may also resist being ridden up or down hills.

Facial expression: A 2014 study by Emanuela Dalla Costa and others developed a “Horse Grimace Scale” as a pain assessment tool, by comparing horses undergoing castration to those experiencing less painful care. They identified six visible signs of pain: the horse’s ears are held stiffly backwards; the eyelid is partially or completely closed; there is muscle tension above the eyes causing the bones to be more apparent; the chewing muscles above the mouth are tense and prominent; the muscles of the mouth are tight and pulled back, causing the horse to have a pronounced ‘chin;’ and the nostrils look strained and slightly dilated. Some horses will also grind their teeth when in pain.

Changing posture: Is your horse standing with one forefoot pointed ahead of the other? Or does he look like a goat standing on a rock, with his feet bunched up close together under him? Both of these positions can indicate discomfort in the feet or hocks. Horses who stretch out as though to urinate while being ridden (but don’t urinate) may be experiencing pain in their backs or muscles that are cramping.

Vital signs: Other indications of pain include a rapid heart rate and unusually fast breathing. In a resting horse, more than 60 heart beats per minute and more than 20 breaths per minute is considered abnormal. Sweating despite not being worked, may also be a clue.

Dr. Henderson said she recommends that people who are competing regularly have a “soundness evaluation” done on their horses in early spring, with a follow-up midway through the show season. This gives the veterinarian the opportunity to identify any issues that could become worse with the intensive work that is required of equine athletes. “Choosing to be proactive in this way results in a happier athlete and a more successful show season,” Dr. Henderson said. She added that this doesn’t substitute for daily checks of the horse and careful observation in the stable and at work, but can be a good way to pick up on potential problems.

Identifying the Source

Sometimes the source of your horse’s pain is relatively obvious. “Certain types of pain produce specific behaviours,” said Dr. Henderson. A horse with colic, for example, will look at his flanks, kick at his belly and roll on the ground. A horse with discomfort in his eyes may hold the eye closed and have tears flowing.

In other cases, the source may be less clear. When your horse is lame, he may favour a particular leg, but it might be more difficult to identify if the pain is in his foot, the joints, the muscles or the tendons and ligaments. To figure that out, you’ll want to look for swelling, hot spots and obvious injuries. A horse who is resisting being ridden could have pain in many body parts – his back might be sore, his legs or feet might be bothering him, or perhaps the bit is hurting his mouth.

Most visceral pain is related to the horse’s digestive tract, but it is also possible for horses to develop kidney stones or inflammation in other internal organs.

A consultation with your vet can be very important to determine the location and cause of the pain. Researcher Dr. Alexander Valverde, of the University of Florida, in his study on equine pain, commented “Pain assessment is far from being definite and objective; not only are there species differences, but also individual variations. In addition, the behavioral and physiological manifestations vary.” Just as humans vary in their ability to tolerate pain and in their response to it, so do horses.

Relieving it

While you, naturally, want to relieve your horse’s pain as quickly as possible, Dr. Henderson pointed out that your veterinarian may need to know how your horse is behaving while in pain in order to determine the cause. It may be helpful to discuss immediate pain relief with the veterinarian when making arrangements for him or her to see the horse.

The most commonly used medications to treat discomfort, according to Dr. Henderson, are nonsteroidal anti-inflammatory drugs (NSAIDs), including Banamine® (flunixin), bute (phenylbutazone), Previcox® (firocoxib) and opioids (including morphine and butorphanol). Dr. Henderson pointed out that the long-term use of NSAIDs can cause ulcers to develop in the stomach and digestive tract, in part because they inhibit the production of prostaglandins, which are an essential part of the protective lining in the horse’s gut. NSAIDs will also increase the acid in the horse’s stomach and decrease blood flow, two more factors that can increase the risk of ulcers. A 2005 study in the Journal of Equine Veterinary Science found that 87 per cent of the racehorses studied had gastric ulcers and 63 per cent had colonic ulcers. This led to subclinical anemia in a significant percentage of the animals, and the researchers felt that NSAIDs were a factor in many of the cases.

To reduce this risk, Dr. Henderson suggests adding supportive treatment with omeprazole (Gastrogard®) or hind-gut products (Succeed®/Smart Gut®) along with any NSAIDs being used. “Sedatives such as xylazine and detomidine can provide short-term relief for pain in the horse’s gut,” she added.

Pain in joints is commonly treated with injections of hyaluronic acid (“joint lube”) and steroids. More recently, treatments with stem cells and platelet-rich plasma (PRP) are becoming more common for joint pain. These treatments can actually repair and regrow the damaged tissues, eliminating the cause of the pain rather than just reducing the inflammation and pain symptoms.

In some cases, depending on the source and cause of the discomfort, surgery is the best option to relieve the horse’s pain and begin rehabilitation.

Again, each horse and situation is unique and a comprehensive plan to relieve your horse’s pain needs to be developed with your veterinarian.

Dealing with Chronic Pain

Acute or sudden discomfort has a protective role in animals just as it does in people – when the horse feels it, he’s likely to take action to relieve the pain and, in that way, prevents further injury.

Chronic pain can sometimes start with an acute instance of discomfort, but it becomes long-term and prolonged, often long after the original injury is healed. In these cases, the nerves become the source of the pain. This happens because the nerves transmitting the pain signals to the brain can influence other nerves near them – even those that don’t normally transmit pain signals – to also become active in sending the “it hurts” message. Then, although the original injury has healed up, the now-sensitized nerves continue to influence each other to keep sending pain signals to the brain.

Other possible causes of chronic discomfort in horses include arthritis, chronic inflammation, back pain, abdominal adhesions, etc. Because some of these may come on gradually, they may go unrecognized until the discomfort is quite serious. Signs Dr. Henderson mentions as indicating chronic pain:

Head shaking or stall weaving
Poor appetite
Horse’s performance deteriorates; resisting movements that he performed without difficulty in the past
Horse’s attitude becomes increasingly negative; he begins avoiding contact with people and sometimes other horses
Horse shows signs of depression such as standing for long periods with his head down

A careful examination by the vet is the first step in developing a pain management plan. Dr. Henderson cautioned that it is not always realistic to expect the horse to become completely pain-free and able to return to his previous level of work.

Rehabilitation

Medication for discomfort control may be very important during the rehabilitation process when a horse has had an injury. Dr. Henderson explained that that isn’t just because we want the horse to be comfortable. Good pain control enables the horse to be taken through a controlled exercise program and perform each movement correctly, so that the injured area can be strengthened. Without it, the horse is likely to resist using the still-sensitive area.

Alternative Treatments

Dr. Henderson said alternative or adjunctive medications can be helpful in reducing pain and healing injuries. She speaks positively about chiropractic and acupuncture treatments, for example. Therapeutic massage, therapeutic ultrasound, laser and shockwaves are also used by some veterinary practitioners. A 2004 study found that chiropractic treatments and massage seemed to increase pain tolerance in healthy horses, giving better results than treatment with “bute.” If you decide to use an alternative approach, be sure to discuss the plan with your veterinarian to ensure that they do not conflict with the program he or she has developed for your horse.

Prevention

Overwork or injuries during exercise are major causes of pain in horses, and there are many steps horse owners can take to prevent these, said Dr. Henderson. “An ounce of prevention is worth a pound of cure.” Dr. Henderson recommends:

Back stretches to help develop core strength. Try holding a carrot in front of the horse to encourage him to stretch forward, or press with your arms on the bottom of his belly so that he rounds his back upward. (See page 64 for more on stretches.)
Cross training to create balanced fitness. “Get out of the sand ring and go for a hack,” she said.
Maximizing turn out time to help the horse stay mentally fit and to stretch and move in a natural way.
Optimal nutrition, including good quality hay, low sugar grains (no molasses), omega fatty acids and vitamin/mineral supplements as needed.
Supplements to prevent repetitive strain injuries. “I recommend Bio-Iso-G® (cortaflex),” said Dr. Henderson. “Research conducted at Michigan State University has shown its effectiveness, unlike many products on the market today.”
Regular hoof care by a knowledgeable farrier can also reduce the risk of injury and pain.

Being Aware

Because horses are not able to tell us when they are in pain, horse owners have a responsibility to pay attention to the sometimes subtle signs that something is wrong. It’s easy to assume a horse has developed a “bad attitude” or is being disobedient when in fact he is hurting. Keeping an eye on all aspects of your horse’s behaviour and working with your veterinarian when you see a change will help to keep your equine friend as comfortable as possible.

Understanding Discomfort: The Gate Control Theory

In the past, some people have suggested that horses (and other animals) don’t feel discomfort the way humans do. Research has clearly shown that this is untrue: horses have pain receptors in various parts of their bodies just as humans do – more concentrated in some areas and less than others. And while horses don’t always express pain in the ways people and some other animals do, the signs are there.

One approach to understanding pain, which applies to both humans and horses, is called the “gate control theory.” This theory proposes that the pain signals being sent to the brain must go through a “gate,” which can be wide open, so the horse experiences maximum pain, or can be partially or fully closed, reducing the horse’s awareness of pain sensations.

What will close the gate? Pain medications obviously do. But both human and animal bodies produce natural “gate-closers” called endorphins. Endorphins flood into our systems during times of pain and stress, giving us some relief. The levels can also be increased by providing positive experiences. If your horse is in pain, you may find that he is calmed or soothed by being gently groomed, for example.

This is also why when a little child gets a skinned knee or a bruise, the parents often offer to “kiss it better.” When the injured area has been lovingly smooched, the child usually smiles in relief and goes back to playing. Why does it work? Not because your kiss is magical, but because that tender kiss from a loved and trusted parent raises the endorphin level in the child’s bloodstream and “closes the gate” to the pain sensations.

The level of endorphins tends to be higher first thing in the morning, so that is a good time to do possibly painful activities (such as changing the bandage on a wound), but also a time when you should be careful if there is a risk that the horse might re-injure himself by exercising too vigorously. Quiet hand-walking can be a better choice.

Research tells us that pain is additive as well. Imagine that your horse has arthritis or another condition causing chronic pain. The pain seems to be manageable because the horse continues to accept being ridden and performs well. However, if something else happens – perhaps he experiences pain in his mouth because of a harsh bit or heavy-handed rider – the accumulated sensations may simply be too much, and he begins to refuse or perform poorly.

This often surprises the rider – why should such a minor problem cause such a big reaction from the horse? The answer: adding this new pain to the already-present pain has opened those “pain gates” still wider.

Our picture of the horse’s experience when he’s in discomfort will always be incomplete, because horses can’t tell us how they feel. But research helps us understand that providing endorphin-boosting positive experiences and reducing or getting rid of other sources of discomfort will help to close the gate and reduce the discomfort as much as possible.