• Rebecca Watson MSc RVN

Winter respiratory conditions in horses

Rebecca Watson advises what to do if you horse has a winter respiratory condition


During the cooler winter months, it is not unusual for your horse to experience some respiratory issues as the environmental air cools and he spends more time indoors than out.


Cold weather alone will not cause respiratory disease but, it can contribute to the horse’s vulnerability to infection; very cold air can cause drying of the tissues that line the respiratory tract, resulting in impaired local defences and potentially increasing their susceptibility to both irritation and respiratory pathogens.

Why do our management decisions matter?

The combination of cold air and winter management choices might influence the health and function of your horse’s respiratory tract; studies indicate that as many as 25–80% of stabled horses suffer from respiratory issues.


The transition from paddock to stable can mean a drastic drop in the air quality. All too often, horse owners are tempted to close windows and doors in barns because they feel the cold. This is very bad for the quality of the circulating air and can contribute greatly to the amount of airway irritants – dust and fungal spores, or indeed, bacterial or viral pathogens, that the stabled horses then breathe in. Bacterial or viral infections thrive in instances where there are a large number of horses housed in close proximity, it is relatively easy for airborne pathogens to spread quickly from horse to horse, through a barn or yard.

If your horse suffers from respiratory disease in the wintertime, it is important to distinguish what exactly, is the root cause of your horse’s condition. Respiratory disease can be caused by:

  • Infective agents (bacterial or viral)

  • Irritants

  • Allergens

Clinical signs of bacterial and viral infections can be similar; cough, dull / depressed demeanour, anorexia, fever. It is important you get your horse examined and diagnosed by a veterinary surgeon, so that you can treat him in the most appropriate manner.



Take precautions

To reduce the spread of bacterial and viral infections in the yard, isolate any sick horses at the first sign of disease. Ensure they are examined and treated by a veterinary surgeon and only reintroduce them to the main population once you are satisfied that they are healthy.


To help reduce the risk of viral infections – ensure that all horses in the yard are up to date with their vaccinations for equine viruses, such as flu and herpes. When a horse has been sick with a fever, it is important to give him time to recover; for the inflammation to resolve and for him to be fully fit before any hard work is asked of him. As a general rule, for every 24 hours he has had a fever, he should have a week off / or light work only.


Biosecurity is of utmost importance, ensure that any horses arriving at the stable yard are isolated away from the main barn for a period of 14 days, so they are not introducing diseases or pathogens to the yard. Once you are satisfied that they are healthy – they can be introduced to the main horse population.


Isolation means stabling the horse away from the main horse population, so that they are not sharing the same airspace and you can minimise the risk of disease transmission. Ensure strict hygiene protocols are followed with regards to tack / rugs / mucking out equipment and handlers. Most importantly, ensure there is no nose to nose contact with other horses.


What are the symptoms?

Inhaling airway irritants can trigger equine asthma. Additionally, because bronchioles and alveoli in the lungs are sensitive to temperature extremes, cold, dry air can increase the risk of bronchoconstriction (airway-narrowing) triggering asthma episodes.

Equine asthma can also be known as:

  • Broken wind

  • Heaves

  • RAO (respiratory airway obstruction)

  • COPD (chronic obstructive pulmonary disease)

Clinical signs of equine asthma include chronic cough (usually dry / non-productive), poor performance and increased respiratory effort, abnormal lung sounds, flared nostrils and ‘heave line’.

If your horse suffers from this chronic condition, several management adjustments can help to lessen the clinical symptoms and help him breathe more easily:

  • Exercise – avoid in the early morning, or late evening, when temperatures are likely to be lower. Also try to avoid dry / dusty arena surfaces.

  • Stable ventilation (make sure windows are always open) airflow is very important

  • Bedding – a dust free option, such as paper is advisable

  • Hay – soaked or steamed hay will minimise dust / fungal spores

  • Ensure bedding and hay are not stored in the barn where the horses are stabled

  • Feed – ensure you feed a good quality feed with no dust particles

  • Feed hay and feed from the ground, so that the horse has his head down (this will encourage natural respiratory drainage)

  • Supplements – if you are feeding supplements, choose liquid over powder

  • Turn out – throw a warm, waterproof rug on him every day and get him out in the fresh air!

  • Bear in mind, that if you are soaking or steaming the hay for one individual and carefully bedding him on paper, he could still suffer the ill effects of dust inhalation if his neighbour is eating dry hay and is stabled on straw or dusty shavings.

Fumes from tractor exhausts or from leaf blowers, or even the dust from sweeping the barn after mucking out, can also set off an asthma episode in a susceptible horse. Make sure you get the horse out of the barn during these times.


If your horse’s asthma cannot be successfully conservatively managed, talk to your veterinary surgeon about long term medication options. Exposure to allergens in the horse’s winter environment can cause an allergic airway response. The primary treatment is avoidance of the offending allergen: using a process of elimination is a good strategy to identify the offending substance (once all other causes of respiratory disease have been ruled out).


Any time you notice coughing or laboured breathing in your horse, seek a veterinary examination to determine the cause of the problem and the best course of treatment action.

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