Respiratory Noises in Horses: How to Identify Early Signs of Abnormal Breathing

Respiratory noises in horses can signal disrupted airflow through the nose, throat, or lungs. While some breathing sounds are subtle or temporary, persistent or unusual noises may suggest irritation, inflammation, mucus buildup, airway narrowing, or another respiratory concern that needs attention.

Because horses are obligate nasal breathers, efficient airflow is essential for comfort, health, and performance. Changes in breathing sounds can provide useful clues about where a problem may be occurring and whether veterinary assessment is needed.

Equine respiratory conditions can have many causes, and some types can escalate into severe breathing impairment. Early recognition is especially important when noisy breathing occurs with distress, rapid breathing at rest, blood or pus-like discharge, or sudden changes in performance.

Understanding the different types of breathing sounds, their possible causes, and the role of diagnosis, treatment, and stable management can help horse owners respond appropriately and support long-term respiratory health.

Equine Respiratory Noises

Respiratory noises in horses can vary from mild snorting or occasional coughing to loud whistling, roaring, rattling, wheezing, or labored breathing. Some sounds occur briefly during exercise, excitement, dust exposure, or cold weather, while others are persistent signs of an airway problem.

The type, timing, and location of the sound can provide important clues. Noises that occur during inhalation often suggest narrowing or obstruction in the upper airway, while sounds associated with exhalation, coughing, mucus, or increased breathing effort may point to lower airway irritation or lung involvement.

Not all respiratory noises have the same level of urgency. A horse that makes a brief noise while clearing dust from the nostrils may not require immediate intervention, but loud, repeated, or worsening sounds should be taken seriously, especially if they occur at rest or interfere with exercise.

Because several airway structures can produce similar sounds, diagnosis often requires more than listening alone. Understanding the major parts of the respiratory system can help explain why different conditions produce different noises and why veterinary examination is sometimes needed to identify the underlying cause.

×

Enjoy $10 Off From Us

What's your top priority with your horse's health?

🦴 Joint Health 🐎 Hoof Health 💪 Topline & Muscles 🥕 Gut Health & Digestion ⚡ Metabolic Health 🏆 Athletic Performance 🌿 Behavior & Calming 💨 Respiratory Health

• Yes, send me expert advice on horse health and nutrition

* Limit one per customer

Equine Respiratory Anatomy

Changes in the way a horse’s breathing sounds may indicate which part of the respiratory tract the problem is coming from. Airflow, filtration, and oxygen exchange all depend on the coordinated function of the nostrils, nasal passages, trachea, bronchi, bronchioles, and lungs. ^[1]

The respiratory tract is divided into upper and lower sections. The upper respiratory tract includes the nostrils and nasal passages. The lower respiratory tract includes the trachea and the lungs. ^[2][3] The trachea is further divided into cervical (within the neck) and thoracic (within the chest) portions.

Within the lungs, the trachea divides into bronchi, which further divide into smaller airways called bronchioles. At the end of the bronchioles are alveoli, small sacs where oxygen moves into the blood and carbon dioxide is released back into the lungs for exhalation. ^[1]

Equine Respiratory Physiology

When a horse inhales, air enters through the nostrils, passes through the trachea and into the lungs. The air is dispersed throughout the bronchi and bronchioles, where gas exchange takes place in the alveoli.

On exhalation, the air ascends back through the same pathway, allowing the horse to excrete carbon dioxide waste produced by the body’s normal metabolic processes. ^[1]

The respiratory system warms and humidifies inhaled air and helps filter out particles. ^[1][3] Large particles tend to collect on the mucus lining of the nasal passages and are moved toward the throat where they are swallowed or coughed up.

In healthy horses, smaller particles and foreign microorganisms captured in the upper airways are neutralized by the immune system. ^[1]

Because horses cannot breathe through the mouth, their nasal passages must accommodate all incoming air. During exercise, these passages expand slightly to increase airflow through the upper airway, helping the horse meet the higher oxygen demands of physical activity.

Any swelling, mucus, inflammation, or narrowing in this region can interfere with airflow and may contribute to respiratory noise or reduced performance. ^[1][3]

Common Respiratory Noises in Horses

Horses with respiratory issues may produce a variety of distinctive noises, each of which can provide clues about the location and severity of airway obstruction or irritation.

These noises include: ^[4]

• Stridor: A high-pitched, harsh sound when the horse breathes in, usually caused by a blockage in the upper airway
• Stertor: A snoring or heavy breathing sound, often caused by a partial blockage in the upper airway
• Whistling: A musical or squeaky sound made when the horse forces air through a narrow passage, usually indicating partial airway narrowing or blockage
• Roaring: A noisy, rough sound caused by air passing through a partly paralyzed or blocked larynx
• Gurgling or choking up: A fluttering or snoring sound heard when the horse breathes in or out, often from mucus or partial airway obstruction

Table 1. Common respiratory noises in horses and what they may mean

What Do Different Respiratory Noises in Horses Mean?

Respiratory noises in horses can occur when airflow is disrupted anywhere from the nose and throat to the lower airways and lungs. Noise during breathing is listed among the signs of respiratory disorders and may include sounds such as grunting. ^[1]

The sound itself does not confirm a diagnosis, but it can help indicate whether the problem may involve upper airway narrowing, mucus in the airways, inflammation, or reduced airflow during exercise. Persistent, worsening, or exercise-related noise should be evaluated in the context of the horse’s other signs.

Signs of Respiratory Problems in Horses

Normal breathing in horses is quiet, regular, and efficient at rest. Horses should not need visible effort to breathe when standing calmly, and their nostrils, abdomen, and chest should move smoothly without exaggerated motion.

Noisy breathing, increased effort, or changes in breathing pattern can indicate irritation, obstruction, inflammation, or impaired airflow.

Signs of equine respiratory disorders include: ^[1][5]

• Coughing that may be dry or may include mucus or blood
• Nasal discharge, including mucus, pus, or blood
• Rapid breathing while at rest
• Labored or difficulty breathing
• Shallow breathing
• Signs of pain associated with breathing in or out
• A “heave” line along the horse’s side, more pronounced after exercise

Respiratory signs should be interpreted in context. A single cough or brief nasal noise may occur after dust exposure or exercise, but repeated, persistent, worsening, or unusual signs warrant closer attention.

Respiratory Noise & Performance Changes During Exercise

Horses may show changes in breathing and performance during exercise even if they appear normal at rest. ^[1] Exercise intolerance, fatigue, or altered breathing effort can indicate underlying respiratory problems. ^[2]

Signs of underlying respiratory problems during performance may include: ^[2][6]

• Noise during exercise, such as whistling, roaring, or gurgling
• Reduced stamina
• Flared nostrils
• Pronounced abdominal effort while breathing
• Excess nasal mucus during or after exercise

Monitoring Respiratory Baselines

Monitoring your horse’s respiratory effort and breathing rate helps you identify changes that may indicate stress, pain, illness, or respiratory distress. Because some horses change their breathing patterns around humans, observe your horse from a distance whenever possible.

Ideally, assess your horse’s breathing when they have been resting for a long period, so recent exercise does not influence their breathing rate or pattern.

To assess respiratory effort, watch for movement of the flanks, nostril flaring, noise with breathing, head and neck position, and use of the abdominal muscles.

To measure breathing rate, count the number of breaths over 15 seconds, then multiply by 4 to calculate breaths per minute. You can watch the horse’s flanks rise and fall, observe movement at the nostrils, or use a stethoscope over the trachea or lungs.

To listen to the trachea, place your stethoscope on the horse’s windpipe approximately halfway up the neck. ^[7] Tracheal sounds are typically louder and easier to hear than lung sounds.

Breathing Check over Trachea
Photo: Dr. Madison Ricard, DVM, PhD, DACVP, PAS

To listen over the lungs, place your stethoscope between two ribs of the horse, approximately halfway down their ribcage and halfway up their body. ^[7] Listen carefully, as lung sounds are typically very quiet.

Breathing Check over Lung
Photo: Dr. Madison Ricard, DVM, PhD, DACVP, PAS

Table 2. Equine respiratory monitoring assessment at-a-glance

When to Call the Veterinarian

Call a veterinarian promptly if noisy breathing is persistent, worsening, or occurs with signs that suggest the horse is struggling to move air through their respiratory system normally.

Respiratory signs can have many causes, and veterinary evaluation is important for identifying whether the problem involves the upper airway, lower airway, lungs, infection, inflammation, or another underlying condition.

Seek veterinary care right away if your horse shows:

• Labored breathing or rapid breathing at rest
• Breathing noise with distress, weakness, or reduced alertness
• Blood, pus-like discharge, or large amounts of mucus from the nose
• Sudden onset of roaring, whistling, gurgling, or choking-like sounds
• Coughing with blood, fever, or significant nasal discharge
• Reduced stamina, exercise intolerance, or performance decline that appears suddenly or worsens over time
• Pale or blue gums

Prompt assessment is especially important when the horse has abnormal breathing at rest, signs of low oxygen delivery, or suspected airway obstruction. Emergency respiratory conditions can progress quickly and should not be managed with stable changes alone.

Intro to Equine Nutrition

Gain a deeper understanding of your horse's nutrition needs. This free introductory course provides a foundation for horse owners to learn how to balance your horse's diet.

Enroll Now

What Causes Noisy Breathing in Horses

Respiratory problems in horses can arise from infectious or noninfectious sources, as well as environmental triggers. ^[2]

Common causes include: ^{[2][6][8][9][10]}

• Viral, bacterial, fungal, or parasitic infections
• RAO or asthma
• Exposure to airborne irritants, such as dust, mold, ammonia, or feed particles
• Poor ventilation or damp conditions

Respiratory Infections

Respiratory infections are common in horses and can cause nasal discharge, coughing, fever, reduced appetite, swollen lymph nodes, and changes in breathing sounds.

These infections may irritate the upper airway, increase mucus production, or contribute to airway inflammation that makes breathing noisier than usual. ^[1]

Common infectious respiratory diseases in horses include: ^{[11][12][13][14][15]}

• Equine influenza: A highly contagious viral disease that can cause fever, dry cough, nasal discharge, lethargy, and reduced performance. Respiratory noise may occur when airway irritation, mucus, or coughing affects airflow.
• Equine herpesvirus: A common viral infection that may cause fever, nasal discharge, coughing, and enlarged lymph nodes. Some strains can also cause neurologic or reproductive disease, so outbreaks require careful veterinary management.
• Strangles: A contagious bacterial disease caused by Streptococcus equi. Strangles commonly causes fever, thick nasal discharge, swollen lymph nodes, and abscesses around the throatlatch, which can interfere with normal breathing in severe cases.
• Bacterial pneumonia: A lower respiratory infection that may develop after viral disease, aspiration, transport stress, or impaired immune defenses. Signs can include fever, cough, nasal discharge, increased breathing effort, and reduced stamina.
• Pleuropneumonia: A severe infection involving the lungs and surrounding pleural space. Affected horses may show fever, painful breathing, rapid breathing, depression, and reluctance to move or exercise.
• Parasitic or fungal respiratory disease: Less common infections can also affect the airways, sinuses, guttural pouches, or lungs, depending on the organism involved and the horse’s exposure history.

Bacterial infections may occur after viral disease because inflammation and mucus can weaken normal respiratory defenses. Infectious respiratory disease may also be more likely when horses are transported, housed in groups, exposed to new horses, or kept in environments with poor ventilation. ^[1][2]

Recurrent Airway Obstruction & Equine Asthma

One common condition that affects exercise performance is recurrent airway obstruction (RAO), also known as heaves or COPD. RAO is an inflammatory disease of the lower airways that causes constriction and mucus accumulation, making breathing more difficult during activity. ^[6][8][16]

Horses with RAO may display exercise intolerance, labored breathing, and respiratory noises that worsen with activity or exposure to dust and allergens. ^[6][8] Related lower-airway conditions are often discussed under the broader category of equine asthma. RAO is the most severe form of equine asthma.

Airborne Irritants & Stable Environment

Airborne irritants and poor stable conditions are common contributors to noisy breathing because they can irritate the respiratory tract and increase inflammation, mucus production, and airway sensitivity.

When horses inhale dust, mold spores, ammonia, feed particles, or other airborne contaminants, these materials can trigger coughing, nasal discharge, wheezing, labored breathing, or reduced performance, especially in horses with underlying airway disease. ^[6][17]

Barn environments can increase exposure when ventilation is limited, bedding is dusty, hay is dry or moldy, stalls are damp, or ammonia builds up from urine-soaked bedding. These irritants may not cause infection directly, but they can compromise normal airway defenses and make existing respiratory conditions more noticeable. ^[6]

Stress

In addition to direct causes, lifestyle and management stressors can weaken immune defenses and increase a horse’s susceptibility to infectious respiratory disease after exposure. In predisposed horses, chronic stress may also contribute to immune dysregulation or inflammatory responses that affect respiratory health.

Potential contributing stressors include: ^[18]

• Transport or frequent travel
• Intense exercise or inadequate recovery time
• Rapid dietary changes
• Inconsistent access to forage
• Limited turnout or prolonged confinement
• Mixing with unfamiliar horses or frequent changes in herd groups

Diagnosing Respiratory Conditions

If veterinary intervention is required for abnormal breathing noises, medical history and physical examination are used to help determine the possible cause and location of respiratory disease. The veterinarian may consider when the noise occurs, whether the horse is at rest or exercising, and whether signs such as coughing, nasal discharge, fever, or reduced performance are also present. ^[1]

Other diagnostic techniques include: ^[1][2][5]

• X-rays of the chest or neck
• Use of an endoscope, a small camera and light mounted on flexible tubing, to view the nose, throat, and airways
• Bronchoalveolar lavage
• Aspiration or retrieval fluid from the space around the lungs
• Bloodwork

These diagnostic tools help determine whether the noise is coming from the upper airway, lower airway, lungs, or surrounding structures. Identifying the source of the problem is important because treatment and management recommendations vary depending on whether the horse has infection, inflammation, airway obstruction, excess secretions, or another underlying condition.

Once a diagnosis is made, the next step is to address the cause of abnormal breathing while reducing future exposure to triggers that can worsen respiratory health.

Management & Prevention

Respiratory disorders often involve the production of excess secretions in the respiratory system, such as in the nose and lungs, which may not be cleared without assistance.

Supportive treatment aims to reduce the volume and thickness of these secretions and make their removal easier. This can involve controlling infection, thinning secretions, improving drainage, or mechanically removing material. ^[1]

Therapies for respiratory conditions may include medications, supportive care, and changes to the horse’s environment. Depending on the diagnosis, medications may include expectorants, cough suppressants, bronchodilators, antibiotics, or diuretics. ^[1]

Environmental management is also important for reducing airway irritation and supporting recovery. Strategies may include improving barn air quality, reducing dust, increasing humidity when appropriate, and minimizing exposure to mold, ammonia, feed particles, and other airborne irritants. ^[1][6][17]

Practical management changes can include using lower-dust bedding, feeding hay cubes or soaked hay, cleaning stalls carefully, and avoiding barn chores that stir up dust while horses are inside. Turnout on pasture and minimizing exposure to known triggers are also recommended for horses with conditions such as RAO. ^[6]

Adequate water intake helps keep respiratory secretions from thickening, making them easier to clear. A comfortable, dry environment with suitable temperature and ventilation also supports rest and reduces unnecessary strain on the respiratory system. ^[1][17]

By recognizing respiratory noises early and reducing common airway triggers, horse owners can help support more comfortable breathing and long-term respiratory health.

Frequently Asked Questions

Here are some frequently asked questions about respiratory noises in horses:

Summary

Respiratory noises in horses are unusual breathing sounds that may happen when airflow through the nose, throat, airways, or lungs is restricted or disrupted.

• Horses rely on their nasal passages for breathing, so clear airflow is important for comfort, health, and performance
• Noisy breathing may include sounds such as whistling, roaring, gurgling, snoring, grunting, or harsh breathing
• These sounds may be linked to irritation, inflammation, mucus buildup, airway narrowing, infection, or partial blockage
• Other signs of respiratory problems may include coughing, nasal discharge, rapid breathing, labored breathing, reduced stamina, or poor performance
• Dust, mold, ammonia, poor ventilation, infections, equine asthma, and recurrent airway obstruction can all contribute to noisy breathing
• A veterinarian should assess noisy breathing if it is persistent, worsening, occurs during exercise, or appears with distress, abnormal discharge, fever, or sudden performance decline