Exercise-Induced Pulmonary Hemorrhage—a common occurrence in barrel horses—may cause blood that originated in the horse’s lungs to reach the nasal passages. BHN file photo

If you ask anyone in the barrel racing industry, few topics will incite a more controversial flood of opinions than ‘bleeders’—horses with exercise-induced pulmonary hemorrhage (EIPH). While some people won’t even consider purchasing a horse that has been diagnosed as a bleeder, others don’t give it a second thought. Any way you slice it, understanding what causes a horse to bleed post-run—and how to effectively manage it—is an important skillset for every barrel racer to have.

According to Dr. Noah Grimes, DVM, of Athens Equine in Athens, Texas, bleeding originates in the caudo-dorsal lung field underneath where the saddle sits. An increase in blood pressure during intense exercise overloads the thin vessel walls, causing the small capillaries that surround the alveoli—the air-filled sacs in the lungs where gas exchanges between the lungs and the venous system— to rupture and fill the airway with blood. While it’s a serious condition, EIPH is usually not career limiting. Understanding the facts about EIPH and developing a good working relationship with a performance veterinarian should allow your horse to continue successfully in a competitive career. 

—>Read more: Understanding EIPH

Myth: I don’t see any blood, so my horse isn’t a bleeder.

Truth:  Because the blood originates deep in the lungs, oftentimes it will not be observed in the nostrils. The easiest way to accurately diagnose exercise-induced pulmonary hemorrhage is by scoping your horse. The ideal timeframe for scoping is between 90 minutes and 12 hours post-run, but evidence of bleeding may still be observed at 48 hours. Because many horses do not show observable signs of bleeding, scoping is a good idea for any horse that is running barrels. If you are unable to scope your horse following a run, you can use a bronchoalveolar lavage (BAL) to help identify the presence of blood in the airways for up to two to three weeks after a suspected bleeding episode.

Myth: Bleeding from the nasal passages and coughing are the only signs of EIPH.

Truth: Expelling blood from the nasal passages and coughing are good indications that your horse may be experiencing exercise-induced pulmonary hemorrhage, but they’re not the only ones. Horses may also sneeze or take longer to recover after a run. Behaviorally, they may be reluctant to go in the gate, may step off barrels or elevate in their turns, or may start crashing barrels due to the frantic drowning sensation they are experiencing during a run. 

Myth: Once a bleeder, always a bleeder.

Truth: Most barrel horses will bleed at least once over the course of their career. Even horses that are known bleeders will not bleed during every run. The bleeding may or may not be observed by the owner. There are many factors that can increase a horse’s risk for bleeding—heightened allergies, environmental triggers, and lung pathologies such as inflammatory airway disease are among the most common—but just because your horse bleeds once doesn’t mean it will bleed again.

Myth: Running on Lasix (furosemide) is hard on my horse.

Truth: Bleeding is harder on your horse than running on Lasix. Every time a horse bleeds, the alveoli in the lungs are damaged. Repeat bleeding episodes result in lung tissue that is scarred and inelastic, making the lungs even more susceptible to future bleeding and further damage. Many people are afraid to administer Lasix because of the possibility of colic or episodes of tying up. These concerns can be mitigated by ensuring the horse is properly hydrated after a run and by administering electrolytes daily or post-run. Managing underlying muscle conditions such as polysaccharide storage myopathy (PSSM) also plays a vital role. 

Myth: It’s OK if I leave my horse a little hay and water after I administer Lasix.

Truth: Lasix needs adequate time to deplete blood volume in the body. Water should be pulled when Lasix is administered. A horse can be given a couple sips of water—no more than an inch in the bucket—prior to making a run. Hay should also be pulled at the time of administration to reduce the risk of impaction colic due to dehydration. Alfalfa hay is a great option for horses that run on Lasix because it soothes the stomach and offers a decreased risk of impaction. Soaked alfalfa cubes offer a nice post-run alternative because they double as an extra source of hydration.

Myth: I need to take it easy on my horse because it’s a bleeder.

Truth: For a horse diagnosed with exercise-induced pulmonary hemorrhage, fitness is key. It is imperative that horses with a history of bleeding are kept in excellent physical condition—running a horse that is not fully fit will always increase the risk of bleeding, but the risk is exponentially increased in a known bleeder. Prolonged low intensity conditioning, like long trotting, is recommended for maintaining a base level of fitness. Galloping the horse once per week to allow exertion and conditioning of the fast twitch muscles is also ideal, and Lasix can be administered, if necessary, for galloping at home.

Myth: My horse isn’t a 1D horse, so it’s probably not going to bleed.

Truth: Horses at all divisional levels in barrel racing are at risk for EIPH. Many times, lower-division horses are running and exerting their bodies’ own personal maximum effort, even if they don’t clock as fast as the upper-division horses. If your horse is maximally exerting itself during a run, it is at risk of experiencing EIPH, no matter what division it is clocking in.

Myth: All methods of Lasix administration are created equal.

Truth: Intravenous (IV) administration is the preferred method for giving Lasix. This is the most accurate method for ensuring absorption rate and timing. IV Lasix should be given three to four hours prior to a competition run. Owners should work with their veterinarian if they are not confident giving IV injections, since damaging the vein with repeated failed administration attempts is the most common concern with this method of administration. 

Intramuscular (IM) injections are also a popular administration route, and they do offer relatively good absorption rates. Lasix given by IM injection needs every bit of four hours to be absorbed, so make sure you are allowing enough time for the Lasix to work. Be sure to swab your injection site with alcohol and practice sterile technique to prevent injection site reactions using this route of administration. 

Oral absorption of Lasix is very poor in horses—only 5-10% of the medication is utilized by the horse’s body, so this method of administration is discouraged. For horses that absolutely will not tolerate an injection, oral Lasix dose is usually doubled. Many horses that bleed through Lasix can be helped by adjusting either the administration route, the timing of the dosage, or both. Any horse that bleeds through Lasix needs to seek veterinary attention prior to increasing the Lasix dose.

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