Management of pain is a key element in veterinary care of horses, especially those with colic, lameness or following surgery. Regardless of the underlying cause, pain control is one of the most important short-term goals when working with horses.
The longer-term goal is to pinpoint as quickly as possible the root cause of the pain so that effective treatment can begin since the pain is often accompanied by severe inflammation or conditions that deeply affect the health of the horse.
According to Chris Sanchez, DVM, College of Veterinary medicine, University of Florida, management of pain is a major part of treatment, and the veterinarian's ability to manage severe pain is an important aspect of equine medicine and welfare.
Pain Management Strategies
Strategies for pain management are of crucial value when it comes to helping a horse recover from disease, injury or surgery. Non-steroidal anti-inflammatory drugs (NSAIDs) are often the initial therapy of choice for relieving pain. One reason for the popularity of NSAIDs is the ease of administering them orally.
Opoid drugs including morphine and butorphanol are used in horses with varying success and are often paired with another agent such as an alpha-2 agonist.
Most of these pain killers, however, have negative side effects including stomach ulcers, diarrhea, and kidney failure, so that choosing the best pain killers available becomes an important part of treatment
Horses under intensive care often display severe pain that is not responsive to a single drug, but multiple drugs used together seem to improve the comfort of these horses.
Problems in pain assessment
Since horses cannot speak to tell owners or veterinarians about their pain, the pain assessment is based on the observer's perceptions. This poses problems because a human often forgets about the inherent differences based on species, age, sex, genetics, environment, source, nerves involved and the length of the stimulus causing the pain.
Severe pain in horses is usually obvious. The horse rolls, paws, kicks, limps, refuses to move or obey lead changes, becomes morose, and/or loses its appetite.
Gut pain such as that in a colic attack can result in decreased motility of the gut, causing additional problems. In cases of severe laminitis or lameness, the horse may limp or refuse to put its weight on the affected limb or limbs.
Horses, like people, are in pain after major surgery. Post-surgical equine pain can affect the speed of the horses' recovery. Horses recovering from abdominal surgery traditionally have been given drugs like Advil or Aleve in humans.
For a large animal recovering from the stress and pain of colic as well as the pain of abdominal surgery that amount of pain relief is most likely minimal.
Research changing methods of pain management
Fortunately, research studies are being done regarding the effectiveness of drugs on alleviating pain in horses, ways to avoid side effects, and better understanding of pain in horses through understanding of horse behavior.
In one study done completed at Washington State University, College of Veterinary Medicine by Debra Sellon, DVM and colleagues, the horses that received 24 hours of narcotics in addition to anti-inflammatory treatment after a common abdominal surgery more quickly behaved like happy horses than did horses that received only anti-inflammatory drugs.
Sellon also noted that, "A few years ago I noticed that post-surgical horses lost their greeting behaviors. The horses stood quietly in their stalls, not greeting people and not even coming over for grain offered in a bucket."
Sellon and colleagues began a study that eventually included 31 horses, all of which had surgery for colic. "It was a double blind study, meaning we researchers didn't know which horses got what," she said. "We scored their behaviors, everything from whether their heads were up, or level, or low, and their ear positions, whether they responded when we called their name and if they'd come when we shook a grain bucket."
That research already is changing the way veterinarians do business across the country. "I've talked with numerous vets who say they are now dosing with narcotics," Sellon said.
According to Margaret-Mary McEwen, DVM, who was involved in the study, he horses treated with 24 hours of narcotics also lost less weight and were able to leave the care of the vets sooner than their nontreated counterparts. "So it costs less for the owners," McEwen said.
Owners usually best able to evaluate pain level
Overall, owners and caretakers of horses are in the best position to evaluate a horse's level of pain. Because they are familiar with the horse's normal behavior, they can best judge when those behaviors change as a result of pain. Working with a veterinarian to diagnose the horse's condition and manage pain is an important part of horse ownership.