- Your horse is a natural show hunter, but you take him to the jumper ring. Why? He’s a “roarer.” Hunter judges won’t pin him because his breathing is noisy.
- Your talented young event horse used to drag you around cross country, but now you’re pushing him to finish.
- Your dressage prospect has Grand Prix talent, but he can’t seem to master the degree of collection needed for the higher levels. When you ask for it, he’s willing—but then he makes a weird gurgling noise, tenses up and shuts down.
Different horses, different problems—but all have conditions that affect their breathing and limit their careers. In this article two leading veterinarians explain how some common problems in the upper and lower airways can lead to poor performance and noisy respiration.
Every cell in your horse’s body (including those of the muscles that power performance) depends on the oxygen he takes in with each breath. So the more you ask of him, the harder his respiratory system works and the more significant these problems become.
Abnormalities in the upper airway can restrict the flow of air and sometimes produce odd noises. Roaring is by far the most common of these noises in sporthorses, says Eric Parente, DVM, who specializes in performance evaluations and upper-respiratory surgery at the University of Pennsylvania’s New Bolton Center. Your horse makes a high-pitched, raspy sound when he inhales, especially when he draws deep breaths at the canter or gallop. The noise is typically louder with effort, fatigue or when your horse is flexed at the poll (which restricts his airway like a kink in a hose), and it may worsen over time.
Laryngeal hemiplegia (paralysis on one side of the larynx) causes roaring. During exercise your horse normally expands his airway to draw in more air by pulling back the two arytenoid cartilages at the opening of the larynx. In this condition, one of the two cartilages doesn’t move or may even sag into the airway as he breathes in. The vocal cord just behind it, which would normally be pulled flat, stays in the airway and vibrates. Usually, it’s the left cartilage, and the root cause is nerve damage. As the nerve supplying the muscle that moves the arytenoid degenerates, the muscle weakens and atrophies.
If the narrowed airway restricts airflow enough, your horse tires more quickly and takes longer to recover because he can’t deliver enough oxygen to his muscles in hard work. How big a problem this exercise intolerance is depends on the degree of restriction and the work he does.
- In dressage, your horse may tire in collected work, when his airway is more restricted, and this may limit him at the upper levels.
- An event horse may be limited in cross country, which calls for maximum effort over an extended time. Fatigue will set in—and as it does, his airway will become even more restricted. But the same horse may do well in jumper competition, where peak efforts come in short bursts.
- Even without exercise intolerance, roaring is a problem in the hunter ring, where the noise is considered an unsoundness and will keep your horse out of the ribbons.
Other sounds—gurgling, fluttering, rasping—appear with some less-common problems that may also affect performance. They include
- epiglottic entrapment. Loose folds of mucous membrane surround the opening to the larynx. In this condition the membrane slips over the epiglottis and traps it so it can’t move to cover the opening when your horse swallows. Besides noisy breathing and poor performance, coughing during exercise is a sign, Dr. Parente says. Inflammation, cysts, abscesses and growths that involve the epiglottis can produce similar signs.
- displaced soft palate. Except when your horse swallows, the soft palate should stay flat on the floor of the pharynx, under the epiglottis. Sometimes, though, it flips over the epiglottis and partly blocks the nasal passages as the horse exhales. Often this happens only in intense work or when your horse is tightly flexed at the poll.