Common Breathing Disorders

As an owner, you may not be in the stable with your horses on a daily basis but you will likely be communicating regularly with your trainer of choice, racing manager, or syndicate manager. It is important to be informed regarding the health status of your horse(s) and along with your chosen professionals, you will be able to make informed decisions regarding their health and performance. Racehorses, due to the nature of working at speed, are susceptible to three common breathing conditions: laryngeal hemiplagia, displacement of the soft palette, and Exercise Induced Pulmonary Hemorrhage.

Laryngeal Hemiplagia:

The larynx is between the nostrils/nasal passages and the trachea and it consists of two cartilaginous flaps that open and close as needed. The flaps (called the arytenoid cartilage) open when the horse is breathing and they close when the horse is swallowing to prevent foodstuffs from entering the trachea. Laryngeal hemiplagia is the paralyzation of one or both of the cartilaginous flaps with the left side being the most commonly affected side; this reason is not understood. In a horse that is not affected with this disorder, the cartilage opens outward to allow maximum airflow as the horse inhales. When a horse is affected, the paralyzed flap(s) does not open outward and this restricts the airflow to the animal.

The disorder is rated on a 1-4 scale with 1 being the minimum score and 4 being the complete paralysis of the cartilage. It is possible to diagnose the disorder with a dynamic endoscope. (A long and flexible tube that is inserted through the nostril/nasal passage and allows a veterinarian to view the throat while the horse is in motion.) Prior to this veterinary examination, the horse may exhibit a few different signs including: a roaring or whistling noise when at work, exercise intolerance, or even a shrinking of the tissues/muscles around the throatlatch (the area at the back of the jaw where the neck ties into the head).

Fortunately, there are a variety of treatment options and the use of a “tie back” surgery is the most common; all options available typically have a good prognosis. This procedure is performed under general anesthesia in a clinical setting and the affected flap is “tied back” (open) to allow the horse to have maximal airflow. If the horse does not respond to the tie back procedure, the removal of the affected flap(s) may be required. Thankfully, horses generally respond well to the procedures and with adequate post-operative care, may go on to high performance careers. As with any biological procedure, complications can arise and range from swelling post-surgery to coughing and breaking the suture. Horses who have had the procedure will likely need to be fed wet food and hay to lower dust risk and irritation of the airway.

Thoroughbreds are not the only breed affected by this disorder but it is most commonly seen in the breed due to the volume of horses and the nature of their workload.

Displacement of the Soft Palette/Flipping

The soft palette of the horse, much like in a human, is between the hard palette and the nasal passage. This soft tissue helps protect the airway from food and other irritants that the horse may ingest by creating a seal over the larynx. When the horse is at work, the soft palette allows the horse to breathe maximally by moving up and down. The term “flapping” is derived from the motion that the soft palette makes when it is moving improperly up and down over the larynx, impending airflow. A horse who is affected by disorder may be referred to as a “flapper”, a “flipper”, or he “flipped” in a race.

There any many outward signs to the displacement of the soft palette with the top two most common being a slight gurgling sound as the horse exhales and also a horse who suddenly stops putting in maximal effort in his gallop or even stops movement altogether. Due to the nature of these symptoms, displacement is a likely diagnosis even if the displacement is not seen on an endoscopic examination performed by a veterinarian. However, a dynamic endoscope can be used on a horse at speed to try to get images of the displacement occurring and to measure the severity of the disorder.

A tongue tie used to tie the horse’s tongue forward in the mouth helps keep the tongue from interfering with the soft palette. Oftentimes you will see horses in the paddock with a two to four inch section of their tongue hanging out of the side of their mouths and that is due to the horse finding a comfortable position to hang his tongue. This is not painful for the horse and it is a cost effective and non-invasive solution to deal with a horse who displaces his soft palette intermittently, especially when paired with a figure-eight noseband (more information about equipment can be found here.) If the displacement is more advanced, there are a few surgical options available. First, a laser can be used on the soft palette with the intent to create a small amount of scar tissue to give the area some rigidity and reduce the chances of displacement. A laryngeal advancement or “tie forward” surgery can also be performed and it is a common choice for treatment. The surgery involves pulling the larynx forward towards the horse’s nose. This makes it harder for the soft tissue to flip onto the larynx, therefore allowing maximal airflow.

Unfortunately, flipping can be difficult to fully correct and the condition can recur despite successful treatments. Your veterinarian will be able to help you determine the best option for your horse

EIPH 

Exercise-Induced Pulmonary Hemorrhage is also known as “bleeding” is a common pulmonary disorder that is commonly associated with a high intensity workload. When the blood pressure rises when the horse is at work, the delicate capillaries in the lungs can burst, releasing blood into the respiratory tract. The blood present may or may not affect athletic performance and is not believed to be painful to the horse. EIPH is not entirely understood disorder but it affects nearly all racehorses and is commonly managed with the diuretic Furosemide, also commonly known as Lasix or Salix.

More information on the topic can be found here.

This article purely informational and is not intended to diagnose, treat, or act as veterinary advice. Please work closely with your veterinary and management team to choose the best treatment options for your horses.

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