Why is My Horse Coughing?

It’s not uncommon for horses to cough, and there are many possible reasons why. Just like people, a cough can be a simple response to dusty conditions or an early sign of something more serious. So how can you tell what’s causing your horse’s cough – and when it’s time to call the veterinarian?

When Armon Blair, DVM, of Ocala Equine Hospital in Ocala, Florida, receives a call about a coughing horse, he starts by asking a few key questions:

• What is the horse’s age?
• Does the horse have a fever?
• When does the horse cough?
• Is the coughing seasonal or year-round?
• How frequent is the cough?
• What does the cough sound like?

These answers provide critical clues to the underlying cause of the cough and help determine whether a veterinary exam is needed.

A coughing horse is a common call for veterinarians, but the causes can vary widely,” says Blair. “Most of the cases I see aren't infectious; they’re typically related to allergies or environmental factors.

What is the horse’s age?

The age of the horse will help to guide the veterinarian’s thought process down a particular path,” says Blair. “If a foal is coughing, it’s more likely a sign of illness, while in adult horses, coughing is most often associated with allergies in the cases I see.

Does the horse have a fever?

“Any time a horse is coughing, it’s important to take his temperature to check if he has a fever,” says Blair. “While a fever doesn’t always accompany a cough, the absence of a fever doesn’t rule out a possible infection.”

Many horse owners only take a temperature when they suspect their horse may be sick, but it’s helpful to check it regularly to know what’s normal for their horse. That way, they can quickly recognize when something may not be right.

When does the horse cough?

It’s important to note the time of day and/or activity that causes the cough. Is it during feeding time? When he’s active or being ridden? Or when he’s in his stall at rest? Coughing tied to exercise or dusty hay may point to irritation, while coughing at rest may signal a more serious concern. These details can help determine how urgent the situation is and whether veterinary attention is needed.

It’s common for horse owners to call when their horse is coughing during feeding time or when exercising,” says Blair. “It’s less common, but more concerning, if the horse is coughing at rest.”

Is the coughing seasonal or year-round?

Noticing whether a horse coughs only at certain times of year or consistently throughout the year can help pinpoint the cause. Seasonal coughing is more often linked to allergies, while persistent, year-round coughing may suggest a more chronic issue.

“In Florida, we see a spike in fall allergies when certain weeds are blooming,” notes Blair. “I tend to see more allergy-related coughing in the fall than the spring, which is often the opposite of what we see in people.”

Blair points out that the winter months in cold climates can also bring an increase in coughing due to management factors, as dust and mold is common from the horses being stalled more. “Dust, mold and ammonia in an enclosed barn can irritate the airways and contribute to coughing,” he says. “When horses are turned out in milder conditions, coughing is more often caused by environmental factors.”

How frequent is the cough?

“If the horse typically coughs a couple of times at the start of lunging or riding and then stops, it’s usually not a major concern,” says Blair. “What’s more worrisome is a cough that’s persistent or notably deep.”

A persistent or deep cough suggests ongoing irritation within the airways rather than a brief response to a trigger like dust or exercise. When coughing continues over time, it can indicate that the underlying issue isn’t resolving on its own and may require veterinary evaluation.

What does the cough sound like?

Pay attention to the sound of the cough – is it a light, hacking cough, or deep and forceful? A light, hacking cough is usually mild, dry and short-lived. It may sound tickly or superficial and often appears only a few times, such as at the start of a ride or during feeding. A deep, forceful cough is stronger, more intense and sounds like it’s coming from lower in the chest. It often requires more effort from the horse and may be repeated or persistent. This type of cough can be accompanied by other signs of illness like nasal discharge.

Veterinarian Exam

A veterinary exam for a coughing horse typically starts with a detailed history and physical evaluation to help identify the underlying cause. A full physical exam will be performed including:

• Taking the horse’s temperature
• Listening to the lungs with a stethoscope
• Checking for other symptoms of illness, such as nasal discharge

“Whenever I'm examining a horse for a cough, I always take his temperature to check for fever and listen to the lungs with a stethoscope to check for abnormal breathing sounds,” says Blair.

Depending on the findings, the veterinarian may recommend additional diagnostics, such as:

• Bloodwork
• Rebreathing exam
• Endoscopy
• Tracheal or transtracheal wash

Veterinarians typically start with a basic inflammatory and infection screening panel through bloodwork. This includes a complete blood count (CBC) to look for signs of infection, inflammation or immune response such as elevated white blood cells. “I may pull blood for a CBC to see what white blood cells are present. Sometimes allergies can be detected this way,” Blair notes, adding that blood test results can also indicate if an infection is present.

In some cases, a serum chemistry panel can be run to assess the overall health of the horse to rule out other underlying issues that could be affecting the horse’s condition.

A rebreathing exam is where the horse is temporarily made to rebreathe exhaled air by holding a plastic bag over the nose for a short period. This causes the horse to take deeper breaths, which helps to amplify normal and abnormal lung sounds.

The endoscopy is performed by inserting a long, flexible camera (endoscope) into the horse’s nostril to directly view the upper respiratory tract. This allows the vet to examine the nasal passages, throat and sometimes deeper into the airway to detect any abnormalities.

We may also do an upper airway endoscopy, or ‘scope’ the horse, looking for mucus in the trachea. Sometimes scoping can reveal the cause of a cough. For example, if there is infection in the guttural pouches, mucus can drain into the pharynx and cause coughing,” Blair explains.

If the cause of the cough is still undetermined, a tracheal or transtracheal wash is usually the next step. Blair says that rather than a first choice, this is typically a “down the road” option for veterinary diagnostics when an infectious lung disease is suspected.

A tracheal wash is used to collect fluid and mucus samples from the lower respiratory tract. The samples are gathered via the endoscope through the horse’s nostril and sent to a lab for analysis.

For the transtracheal wash, the horse is sedated and given a local anesthetic. A small incision is made in the neck, and a catheter is passed into the trachea so sterile saline can be infused into the airway. This fluid is collected back out and sent to the lab for culture and cytology. These results will guide the veterinarian to the appropriate treatment and medication if needed.

Cough Treatments

Treating a horse’s cough depends entirely on the underlying cause, so it’s important to identify why the horse is coughing with the help of a veterinarian.

If a cough is related to environmental irritants or allergies, management changes such as reducing dust exposure by soaking hay, improving barn ventilation, removing moldy bedding, or increasing turnout time can make a big difference.

“You don't want to overtreat an occasional cough,” says Blair. If a veterinary exam reveals the coughing is caused by allergies, one of the first lines of defense is to treat the horse with antihistamines to help reduce airway inflammation.

Another option for horse owners is to try an over-the-counter cough remedy, like Farnam’s Cough Free® Respiratory Health Pellets. Cough Free® supplement is designed to provide daily respiratory support in horses experiencing stable cough, dry cough or seasonal allergies due to environmental factors, such as pollen and dust. Its unique, show-safe formula combines herbs and minerals in palatable, easy-to-give pellets that are perfect for stabled horses with limited or restricted turnout that may struggle from ammonia build-up or lack of air flow in a dusty stall to help maintain respiratory health.

If an infection is present, the veterinarian may prescribe antibiotics along with supportive care, like rest and hydration. For horses with chronic respiratory conditions, systemic anti-inflammatories (corticosteroids) may be recommended.

Smart Horsekeeping

Smart horsekeeping plays a major role in preventing and managing coughing in horses since many causes are linked to the environment. Simple, consistent management practices can make a difference in air quality and your horse’s comfort. Here are some steps you can take to ensure your stable management practices aren’t contributing to your horse’s coughing:

• Reduce dust exposure by soaking hay, using low-dust bedding and avoiding sweeping or blowing dust near horses.
• Maintain a daily stall cleaning routine, making sure to remove ammonia-soaked bedding.
• Turn horses out while cleaning stalls and aisles.
• Increase turnout time so horses can spend more time outside in the open air.
• Adjust turnout times to later in the day when pollen counts are lower.
• Improve barn ventilation by opening windows and doors to increase fresh airflow and help minimize the build-up of ammonia, mold spores and airborne particles.
• Don’t store hay or straw in loft areas directly over stalls.