Respiratory Problems in Horses - RAO, COPD and SPAOD

hay should be dust freeIf your horse or pony has a respiratory problem such as a cough, he wheezes or is short of breath he could be suffering from Recurrent Airway Obstruction (RAO) or Summer Pasture-Associated Obstructive Pulmonary Disease (SPAOD) - also known as chronic obstructive pulmonary disease (COPD).

Horses and ponies suffering from these conditions need special care and management to allow them to live a comfortable and active life.

Difficulty in breathing causes the horse's flanks to heave - hence equine respiratory problems have been traditionally known by many horse owners as "Heaves". This condition is also described as "broken wind", "hay-straw allergy" or emphysema.

RAO and SPAOD both affect the smaller airways of the lungs and affect the horse's capacity and ability to breathe. These diseases cause thickening of the airway walls and the secretion of excess mucus.

RAO is an equine disease affecting the horse or pony's lungs. It is also referred to as chronic obstructive pulmonary disease (COPD) although some equine veterinary surgeons now prefer to use the description of RAO as there is also a human disease called COPD.

RAO is mainly caused by exposure to dusts and moulds, especially in bedding and feed.

SPAOD (summer pasture-associated obstructive pulmonary disease), produces similar symptoms to RAO / COPD but has different causes. It is is associated with the pollens and dust particles that a horse is exposed to during the summer months, especially when it is very hot and humid.

Up until fairly recently, SPAOD was originally found mainly in the South East of the USA, now more cases are being seen elsewhere in the world, especially in the UK. This could be due to climate changes as a result of global warming. SPAOD occurs in the UK in horses that are kept out at grass during warm and humid weather conditions.


Another equine respiratory disease is Strangles. This is highly contagious and most commonly seen in young horses. Symptoms of Strangles include a high temperature, enlarged glands under the jaws, thick nasal discharge, a high temperature and a cough. The swollen glands may form abscesses which burst. Older and very young horses and ponies are more susceptible to strangles.

If you suspect that your horse may have Strangles call your vet immediately. The horse or pony must be isolated to try to contain the spread of the disease. The horse may have difficulty in eating, in which case a gruel can be fed.

A long rest period is necessary following an episode of Strangles to ensure that no permanent damage is done to the horse's respiratory system.

It is essential to have these conditions correctly diagnosed and treated by a veterinary surgeon.

Care of horses & ponies with respiratory problems

  • Keep horses suffering from RAO or equine COPD turned out at grass as much as possible - ideally this should be for 24 hours a day.
  • Remove hay from the horse's diet and get an alternate source of fibre such as haylage.
  • If your horse has to be stabled ensure that all bedding and feed is as free of dust and mould spores as possible.
  • Don't groom or muck out your horse while he is still in his stable as this will expose him to more dust.
  • Good ventilation is always essential for the respiratory health of your horse or pony.
  • Never work your horse in a dusty arena or school.
  • Feed your horse at floor level - lowering his head will help to clear secretions from his lungs .
  • Discuss a care and management regime with your vet

Causes of RAO, COPD and SPAOD

  • Horses suffering from RAO, COPD and SPAOD illnesses are usually over six years old.
  • RAO / COPD is common in horses that are kept in a stable for long periods. As many as 80% of horses who spend some part of the day stabled have been found to have some airway inflammation.
  • Respiratory problems can affect any type, height or breed of horse or pony
  • The environment in which a horse is kept, and repeated exposure to dust and mould spores is the primary cause of Recurrent Airway Obstruction

Veterinary Treatment of Heaves

The two main equestrian treatments for respiratory disases are drugs that dilate the bronchioles and those that decrease the inflammation within the lungs.

One option is the drug clenbuterol (Ventipulmin) which is given orally twice a day.

The other group are corticosteroids, which function to reduce the inflammation occurring with respiratory illnesses.

It is also possible to use certain human asthma drugs in the horse using a tight fitting mask. Your veterinary surgeon can advise you on this.

bales of hay

Signs of Respiratory Diseases in Horses

One of the first indications that your horse has a respiratory problem is repeated coughing as he trys to shift the mucus in his airways.

This coughing usually occurs when he is kept in dusty conditions or exposed to mould spores. The symptoms can also show up when a horse is being exercised.

If the problem is not spotted early enough and the horse or pony continues to be exposed to dust and moulds he may then show symptoms of a runny nose. He may also lack energy in his work and become breathless in faster work.

He may also show laboured breathing and flaring nostrils when at rest.

Some animals deteriorate to the point where they have breathing problems whenever they experience a dusty or mouldy environment.


Diagnosing the type of equine respiratory ailment a horse may involve any of the following veterinary techniques:

  • Ultrasound
  • Radiology
  • Endoscopy - A thin fiber-optic scope is inserted into the horse's nostril and then up through the nasal passages into the trachea and larger bronchi for examination.
  • Transtracheal wash - Fluid is flushed through the trachea via a small tube inserted into the windpipe. The fliud is then removed for analysis of bacterial content.
  • Bronchoalveolar lavage - A more representative sample of cells is collected via a tube inserted deeply into the lung airways.
  • Pulmonary Function Testing.

Soaking hay

Soaking your horse's hay before feeding can control the dust and mould spores which cause respiratory illnesses. A better alternative is using a hay steamer to steam hay

If you can only get poor quality hay it would be better to switch to an alternative such as haylage rather than soaking the hay.

  Care and management of Equine Respiratory Problems - coughs, broken wind,heaves,
  Recurrent Airway Obstruction - RAO, chronic obstructive pulmonary disease - copd and
  SPAOD in Horses and ponies