Trooper has not been properly diagnosed with this condition but I am pretty sure he has it. He used to get a cough every year at the end of the winter before he was going to go out in the field at night. Once he was out at night it would go. The vet would come and see him for his cough and he has been on ventipulmin (to open the airways) and sputolosin (to bring up any mucus). He is also a very loud breather when you ride him but he does get himself a bit excited which will add to this.
As he is now 22 years old it has gradually been getting worse and this year it was quite bad as it was paired with him being quite over weight. We had the vet out this year because of his cough and she said his chest sounded clear. If he was to be diagnosed with RAO he would need endoscopes doing and he doesn't like the vet so I think this would be a bit tricky! When I was riding him I would go into trot and he would cough so I would have to walk again. Sometimes he would stretched his neck right out like race horses do when they are trying to get more air down their airways. He would also breathe a pattern of 3 sometimes, he would take 3 short breaths then there would be a break. I don't know if the noise was him breathing in or out though. I also think he has a bit of a"heave line", I tried to take a photo of this but as he is black and it isn't very severe it didn't show up well.
Photo of a heaves line (image from Knottenbelt, Pascoe and Saunders, Diseases and Disorders of the Horse)
He is much better now though as he has lost weight and that paired with Winergy Ventilate (Click here for Winergy Ventilate review!) have made him return back to normal. Also I should say he is on shavings not straw and isn't on any hay or haylage at the moment, only grass, so there is no need for anything to be soaked. However, his stable is next door to where the hay is kept which I don't think is helping it! As he gets older I think it is important we keep him as fit as possible in order to keep his respiratory system healthy.
RAO is the horse equivalent to asthma in humans. It is an allergy (type 1 hypersensitivity), to the spores of mould that are often seen in dusty hay. When horses eat the hay the spores will be concentrated around their nose and are easily breathed in. This leads to an inflammation in the lungs.
In humans, breathing in is an active movement in which muscles are used and breathing out is passive, due to the muscles relaxing the rib cage coming down pushing the air out. In horses, breathing out is half active and half passive, as is breathing in. When horses have RAO they often have forced expiration as they struggle to expel the air leading to a double breath out (which is what I think Trooper was doing when I was riding him and he was breathing in a pattern of 3). Horses can get heave lines due to the forced expiration. This can also lead to emphysema which is bursting of the alveoli in the lungs and is irreversible.
There are a number of other respiratory conditions that are contagious and very serious. These include strangles, equine influenza and rhodococcal infection. Veterinary advice should be sought if you think your horse has any kind of respiratory problem.
There are lots of horses that go on to have high performing careers with the condition. I think Trooper is much better now and it is very important we keep his weight under control. If anyone has an tips from their own experiences with RAO then please let me know!