The term COPD is not being used for horses anymore, as COPD is a term used to describe a condition in humans that smoke.
In horses, it is called RAO (Recurrent Airway Obstruction) or heaves, and is more similar to human asthma.
The best treatment you can provide your horse is a complete change in her environment. She needs to be permanently moved from the barn to the pasture, as RAO is triggered by the inhalation of dusts, like the dusts present in hay and bedding materials.
If that is not possible, you need to keep your horse as close to the door as possible, or in the most well ventilated area of the barn. Only soaked hay should be fed to RAO horses. Pelleted feed should be fed as an alternative.
One important thing to know is that the inhaler medications are rescue/emergency medications and should only be administered during an acute episode to alleviate respiratory distress.
The duration of action of the majority of inhalers in the market, such as albuterol and pirbuterol, is less than 1 hour, and thus they are emergency medications rather than treatment. There is one oral bronchodilator used for horses (Clenbuterol, or Ventipulmin), and the duration of action is up to 8 hours. But you should not use the bronchodilators in the place of changing the environment the horse is housed in.
The use of steroids is recommended especially if you are going to keep your horse indoors. The steroid of choice is generally dexamethasone, but that needs to be given intravenously. If you are giving an oral steroid, it is probably prednisone or prednisolone.
Prednisone is ineffective for the treatment of heaves, as it has to be transformed in the body into prednisolne before it becomes active. Check your label, and if it is prednisone you're administering, you should wean your horse off of it. It is not doing her any good, and is obviously harming her.
I can't reinforce it enough, the only way to bring your horse to complete remission is to keep her outdoors year-round.
