“Since horses can’t talk, it is important for the owner or trainer to know the horse as well as possible so that when there is a change in performance, attitude or behaviour they can address the issue promptly,” says Kathleen MacMillan, assistant professor (Equine Ambulatory) at the Atlantic School of Veterinary Medicine. “Just like humans in pain, horses will demonstrate a wide range of signs and behaviour, depending on the location and severity of the pain.”

Dr. Katharina Lohmann, associate professor of Large Animal Medicine at the Western College of Veterinary Medicine in Saskatchewan, adds, “Horses are prey animals, so they tend to try to hide their illness or pain, especially around people they don’t know. Some horses are very stoic, so you have to be careful and aware of the subtle signs that the horse is hurting.”

Some signs that a horse is experiencing pain include:

  • lameness, or taking the weight off one foot while standing
  • looking at the flank, pawing, lying down, rolling, or grunting indicates abdominal pain
  • sweating
  • increased heart rate
  • glassy eyes or an anxious expression
  • snorting or whinnying frequently
  • tail swishing or general restlessness
  • reluctance to accept the bit, not eating, or chewing in an unusual manner (mouth ulcers or dental pain).

Common medications

Pain is often a key factor in diagnosing the problem, and while nobody wants to leave a horse suffering, Lohmann says, “If we give too much medication, it can make it harder to figure out what is going on. If the horse has colic, for example, I need to know how the pain is changing to determine if surgery will be needed.”

The most common pain medications used for horses are the NSAIDS (non-steroidal anti-inflammatory drugs) phenylbutazone and Banamine® (flunixin meglumine). “These are very effective, but come with some significant side-effects,” says MacMillan, including gastric ulcers and toxicity, and should only be used under the advice of your veterinarian. Horses taking these medications may be given Gastrogard® (omeprazole) to help protect the stomach lining. There may be effects on the kidneys as well, especially if the horse is dehydrated. Other pain medications include steroids (dexamethasone); local anesthetics (lidocaine); opiates or narcotics (morphine); alpha-2 agonists (xylazine); and dissociative anesthetics (ketamine).

Some medications may appear in the horse’s blood or urine for a period of time; so if your horse is competing, you need to talk to your vet about the length of time that the drug will still be detected in testing. (For a list of prohibited and controlled medications in FEI-sanctioned events, see prohibitedsubstancesdatabase.feicleansport.org)

MacMillan recommends that a horse on pain medication be hand-walked or lunged at slower speeds rather than turned loose in a paddock. “Some horses on stall rest require some medication to calm them down, so they are less likely to injure themselves bouncing around in the stall,” she says. Reducing the amount of grain in the horse’s diet can help as well. MacMillan adds, “There is always a risk that as the pain decreases, the horse will feel better to the point that he will exercise more freely, further injuring the leg.”

Of course, the ultimate goal is to find and treat the cause of the pain. MacMillan says, “Lameness is something that just about every horse owner deals with at some point. Early recognition and intervention by a veterinarian can play a very important role in successful treatment and resolution, resulting in a better prognosis for long-term soundness.” This applies to other sources of pain as well.

On the other hand, not all causes of pain can be resolved. “Some horses have chronic conditions that can’t be cured, and we treat them with pain medication both to make them comfortable and so that we can use them for riding or other activities,” says Lohmann. “I think in these cases we need to think about the ethical implications of medicating a horse so it can be ridden.”

Alternative therapies

“There is a lot of interest in both human and veterinary medicine to use holistic approaches to manage pain and diseases,” says MacMillan. Chiropractic manipulation, acupuncture, and massage therapies can all be effective non-drug alternatives, but as not all veterinarians have expertise in these treatments, owners interested in trying them may need to search for experts in those fields. “Laser therapy has also been very helpful to manage acute inflammation, as well as speed up wound healing and tendon/ligament injuries,” says MacMillan.

Lohmann recommends using cold water or hydrotherapy for acute injuries, which can decrease swelling, inflammation, and pain. Ice may also be used to relieve pain. “If a horse has foundered, for example, putting his feet in ice can help.”

Holistic and naturopathic practitioners will vouch for a number of herbs that can help relieve minor pain in horses. Devil’s Claw, chamomile and calendula all have anti-inflammatory properties; arnica is good for soft-tissue injuries or sprains; and willow is an analgesic often called “natures aspirin,” to name just a few. (Ed note: always consult with your veterinarian before using any products/substances for pain control, whether alone or in conjunction with pharmaceuticals.)

“We still have a lot to learn about pain in horses and how to understand and manage it,” adds Lohmann. “The horse owner’s understanding of the horse is crucial. Often the owner will say it was just something different about the horse’s expression or eyes that let him know something was wrong, giving us the first clue to the problem.

Morphine – an old drug making a comeback?

Morphine is an opiate derived from the juice of the opium poppy that has been used as a potent painkiller for centuries. Morphine produces its pharmacological effects by binding with the opioid receptors in the brain and central nervous system. In horses, morphine stimulates locomotor activity, causing agitation while suppressing pain and prolonging endurance – giving opiates a long and suspect history in racing circles.

In veterinary practice, morphine sulfate is used as a narcotic analgesic to relieve moderate to severe pain, and also as a pre-anaesthetic agent for some surgical procedures. Decades ago, morphine was commonly used by vets for equine patients, but in the years since had fallen out of favour somewhat. At the “Medical Pain Management” table discussion at the 2012 AAEP Convention, Dr. Debra Sellon of Washington State University noted that there has been a recent resurgence in the use of morphine for pain control. In the right circumstances, morphine can be a very economical and effective alternative that can also work well in conjunction with bute or banamine.

On the 2013 FEI Equine Prohibited Substance List, morphine, previously classified as a Banned Substance, has been re-classified by the FEI Bureau as a Controlled Medication due to its increasingly common legitimate use in equine medicine.