Treating IAD—Inflammatory Airway Disease in Horses

Written by Veterinary Surgeon Hugh Dillon
Wednesday, October 12, 2016 — No Comments Yet

By the time a horse crosses the finish line in a five furlong race, has completed a Grand Prix show jumping round, or gone one sixth of the way around a 3 star cross country course, he will have somewhere around 1,800 litres of air in and out of the lungs. Roughly this equates to moving two five gallon buckets of air into and out of the lungs every second.

These examples underline the importance of the respiratory system. The harder a horse works, the more oxygen it needs and the more air it must move into & out of the lungs. In fact these are so tightly coupled, that if a horse doubles it’s speed, it will need twice the amount of air moved into & out of the lungs.

The horses’ respiratory system, is the second most common cause of depleted performance in competition, second only to lameness. It clearly deserves our attention & the advancements being made in treating respiratory issues in horses. For most Veterinarians, the following conversation is a regular occurrence, but Hugh Dillon, an Irish Veterinarian has emphasized the importance of moving with the times & advancements in nebulisation technology to help horses with IAD, live happy healthy & competitive lives.

 

Why does your horse get out of puff when galloping and blow very hard after exercise?

Whether it’s on the hunting field or racecourse, horses that get short of breath will not perform well. As well as the obvious causes such as unfitness or respiratory infection, there is another cause which is an allergic condition called Inflammatory Airway Disease (IAD). This is very common especially in stabled horses.

Owners see various symptoms including an occasional cough, mild nasal discharge, poor exercise performance & delayed recovery after exercise. Otherwise the horses are very well and there is usually no improvement with antibiotics. The condition can range in severity from very mild (maybe losing three lengths in a race) to very severe (pulling up in distress).

 

How can I detect if my horse has IAD?

It can be difficult to diagnose in mild cases. Veterinarians will use a combination of horses history, clinical signs & and endoscopy examination of the windpipe after exercise and a lung wash. It’s important to distinguish the condition from bacterial or viral infection.

Horses that are otherwise well but have a low grade occasional cough, increased breathing rate in the stable, mild nasal discharge & get tired at exercise too quickly should be investigated for IAD. Trainers sometimes mistake IAD for a choker or other laryngeal problems. Some horses with IAD will also be more prone to bleeding at exercise.

 

What’s the best way to treat IAD?

No two cases are the same and all horses will respond differently to treatment. It is worthwhile for owners/trainers to work closely with you their veterinarian and to persevere until the right therapy is found. Firstly the owner should provide as much fresh air as possible and we often advise to leave the horse turned out in the pasture 24/7. Otherwise, the stable & barn must be kept a dust free as possible and to either soak or steam hay. Feed hay from the ground & not from a hay net or wall mounted hayrack. The stable should be kept really clean, removing droppings, urine spoiled bedding, old feed & hay daily. The ventilation must be excellent with no hay or straw stored nearby. In addition to management, there are many drugs, herbal & traditional remedies that have been used for years with varying success. Veterinarian advice re drugs to counteract the symptoms of the disease and these can be used in combination with the more traditional therapies such as garlic & honey for example, is vital to successful treatment.

 

Have there been any recent advances in therapy in the condition?

For many years, work has been done on developing an efficient nebuliser which is a face mask that can deliver drug therapy directly to the lungs. Treatment this way is much more effective and requires smaller dose administration of medications such as cortisone.

The earlier models have been slightly cumbersome, fragile & slow to deliver medication. The most recent nebulisers are very flexible, light, robust easy & efficient to use. One such system has been developed by an Irish company Nortev, is called Flexineb.

It’s designed to aerosolise a wide range of drugs including corticosteroids, eucalyptus oil, bronchodilators, saline and if needed antibiotics. As all horses are different, it is important to draw up the most suitable protocol for the animal, your client & to vary treatment if needed. Flexineb has been developed to deliver optimum particle size to the lungs, scintigraphy studies show that 71% of the nebulised drug is delivered to the lower airways, with the remaining 29% into the upper airway & trachea.

Personally I find this more modern nebuliser easier to use than its predecessors. It involves about 5 to 10 minutes twice a day for application. The mask is placed comfortably above the horse’s nostrils & the medication is inhaled in each breath taken by the horse and is drawn right down to where the oxygen is transferred to the bloodstream (the 71% of drug delivered to the lower respiratory system). The condition IAD causes inflammation in this area, and the exchange of oxygen is hampered. With the use of nebulisers and face masks the required medication is very effectively delivered to where it is needed. Thus we can use very accurate and high doses of a specific medication without burdening the rest of the body with such doses. The medicine hits the spot without having to pass through all organs of the body.

The profession welcomes this new Irish designed & manufactured product and hopes its increased use will lead to better outcomes in the ongoing treatment of IAD.

 

Hugh Dillon is an esteemed partner in one of Irelands main Equine Hospitals, Troytown Greyabbey, in the heart of The Curragh, Co Kildare. 

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