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Sound Check: Learn To Listen To Your Horse’s Lungs, And Know When To Call The Vet

The noises that can be heard when listening to a horse's lungs can offer a lot of insight into his health. Purchasing an inexpensive stethoscope and learning how to use it proficiently can help a horse owner or caretaker know when something may be amiss with his respiratory health.

Practicing stethoscope use on a horse that is healthy can help horse owners know what is “normal.” To learn proper use, the horse should be placed in a quiet area away from excess noise. Place the stethoscope five inches behind and seven inches above the horse's elbow. Ask a helper to restrict the horse's nose so you can hear changes in lung sounds as the horse takes deeper and more shallow breaths.

Healthy lung sounds like gentle blowing, but this can be hard to hear between the horse's gut noises and heartbeat.

If you hear squeaking, loud noises over a large area or bubbly noises, call your veterinarian.

When Is A Cough Just A Cough?

Almost everyone knows that one horse who coughs when his rider first gets on. His cough may sound like he's clearing his lungs or the horse may stop moving, throw his head down and cough from deep in his lungs. Most of these horses then go right back to work, happy to do their job, with no more coughing episodes.

A horse who coughs a few times at the beginning of a ride may be clearing mucus from behind his larynx. Some horses create more mucus than others, so a cough for them is normal. If the horse has no other trouble breathing and isn't ill, his coughing may be a natural reaction to beginning work, when he breathes deeper.

A horse coughs when his esophagus is irritated by something, whether that's dust, pollen or cold air. The horse rapidly expels air in an effort to remove irritants from the respiratory tract; this is the cough that is heard.

Prolonged coughing or coughs that become more frequent, a call to the veterinarian is warranted.

Proper Training Doesn’t Just Make Horses Faster — It Changes Their Organs

Proper training of the equine athlete can produce results in more than just muscle mass: it can and should create physiological changes in the lungs, spleen and heart.

Proper athletic conditioning can increase the actual size of the heart, which is a factor in cardiac output. Cardiac output is a combination of heart rate and stroke volume. The more blood that pumps through the heart, the more oxygen arrives at the muscles.

A horse that has been trained properly will have healthy lungs, which can take in more oxygen. The oxygen is then carried by the blood and distributed to the muscles. Called maximum oxygen uptake, this process provides power for a longer time. If all other equine systems are in order, the horse's performance level is directly related to maximal oxygen uptake, which can increase by 35 times between rest and intensive exercise.

Athletic conditioning also affects the spleen, which acts as a filter for blood and a blood storage area. Correct training increases the spleen's capacity to hold blood. It also makes the spleen more efficient at contracting during exercise, which forces more blood cells into circulation.

Proper training also enlarges the capillary network within muscles, allowing more blood to be delivered in a shorter amount of time.

Study: Heaves Can Wreak Havoc On More Than Just Lungs

Horses with uncontrolled respiratory disease have more organs at risk than simply their lungs, new Canadian research shows. Drs. Serena Ceriotti, Michela Bullone, Mathilde Leclere, Francesco Ferrucci and Jean-Pierre Lavoie have discovered that horses with uncontrolled respiratory disease are at risk of having pulmonary arterial changes that could lead to heart failure.

Horses that suffer from severe equine asthma have inflamed airways; they also cough and have difficulty breathing. The researchers hypothesized that this condition, which is triggered by dust and mold in a horse's hay and environment, can put horses at risk of pulmonary hypertension. Pulmonary hypertension occurs when the walls of the pulmonary arteries thicken and increase the horse's blood pressure.

For the study, the research team obtained multiple post-mortem lung samples from 18 horses: six that were in heaves episodes when they died; six that were in remission from heaves from being kept in a dust-free environment; and six that had no heaves and served as controls.

The researchers measured the thickness of the arteries and found that horses with uncontrolled asthma had thicker arterial walls than other horses in the study.

Why the artery walls thicken when a horse has breathing trouble is unknown, but it is hypothesized that the low oxygen content and inflammation may increase the amount of smooth muscle in the artery walls, which makes it more difficult for blood to move out of the lungs. Eventually, this condition could lead to an enlargement and failure of the right ventricle of the heart.

The final part of the team's study focused on potential treatments for pulmonary hypertension in horses: they used 11 asthmatic horses divided into two groups that were treated for a full year with two different treatment protocols. One group had reduced dust exposure, primarily through the feeding of hay alternatives. The second group went on a corticosteroid for the first six months, the had dust control measures added in. Both treatments led to a reversal in arterial wall thickness, but changes in the second group were not seen until the dust control measures were taken.

They scientists determined that the thickening of arterial walls in horses with heaves can be reversed, but environmental changes must be made; the administration of corticosteroids, while helpful, must be made in conjunction with changes in management.

Read the full study here.