Key Facts:

• Allergic respiratory disease is usually caused by moulds, organic dust and bacterial toxins found in hay and straw.

• It is best managed by avoiding exposure to these allergens through bedding on shavings or cardboard and feeding haylage or dust-extracted dried forages.

• Forages rich in antioxidant nutrients or dietary supplements may provide additional benefit.

Recurrent airway obstruction (RAO) is the equine equivalent of asthma. It is also known as heaves and was previously referred to as chronic obstructive pulmonary disease or COPD. Around 10% of horses are affected by RAO, the signs of which include coughing, nasal discharge, exercise intolerance and laboured breathing.

The disease is triggered by the inhalation of moulds, organic dust and bacterial toxins present in hay and straw. It is most commonly seen in stabled horses during the winter months, although horses at pasture can be affected by exposure to pollens and dust during the summer months. Diagnosis is usually made on the basis of clinical findings, supported by endoscopy and results of laboratory tests on fluid collected from the lower airways.

The most important treatment for RAO is to reduce exposure to the inciting allergens in hay and straw. This requires bedding on dust-free shavings or cardboard, as well as feeding soaked hay, dust-extracted forages or haylage. Additional drug therapy may be required initially, for the first week or so, while these management changes are instituted.

Of the dietary options, soaking of hay is arguably the most demanding and least effective. Prolonged washing of the hay is necessary to remove all the allergens but this can also remove key nutrients. Pressurised hay steamers are more effective, with minimal nutrient loss, but are expensive.

Haylage may be inappropriate for certain animals that are prone to weight gain or suffer from underlying gastrointestinal problems such as gassy colic. Care must also be taken with larger haylage bales, which can dry out and become very dusty in warmer weather.

Forage products from Halley’s Feeds are ideal for all horses and ponies with RAO. Because they are dried extremely quickly, usually within 1 hour of being harvested, and at a high temperature there is not the build-up of moulds, organic dust and bacterial toxins that occurs when hay is left to dry naturally over the course of several days or subsequently stored poorly in a barn. Furthermore, any dust that might be present is extracted during the subsequent cooling process, ensuring minimal potential to trigger RAO.

Recent research has shown that vitamins with anti-oxidant properties can help in the management of RAO. Feeding rapidly dried forages, such as those from Halley’s Feeds, that have preserved levels of these vitamins is of benefit.

Alternatively an appropriate dietary supplement can be fed.