HOW TO MANAGE EQUINE ASTHMA
”Equine Asthma”- yep, that's the new name for "heaves," "RAO," "COPD" or whatever else we've called it over the years!
There are two types of this condition, “summer-pasture-associated” and “classic” recurrent airway obstruction (RAO).
Summer-pasture-associated horses tend to be triggered by spring/summer allergens like grasses and trees, and “classic” horses tend to be triggered by barn dust and mold spores. Most horses in our area of North Carolina are "Summer-Pasture-Associated" asthma patients, so we recommend starting yearly treatment or management in March or April. It’s important to know, however, that some horses can have BOTH types, and will need to managed year-round!
What are your treatment and management options? Read on below!
MEDICATIONS:
There are a few medication protocols for horses with Equine Asthma.
Option 1 is the cheap/easy route, but comes with risks. This involves treatment with a systemic steroid (usually dexamethasone or prednisolone). The steroids are usually given orally, but we may want to start with injections for a week or so in severely affected horses. Cost is <$50/month, it’s easy, and it’s usually very effective. The downside is that it can cause laminitis and can suppress their immune system. It is most risky in horses that have metabolic disease like Equine Metabolic Syndrome (insulin resistance), PPID (cushings), or those that are overweight.
Option 2 is the Aservo Equihaler. (PLEASE NOTE- THIS PRODUCT IS BEING DISCONTINUED AS OF 2024) This product is a hand-held device that administers an anti-inflammatory mist into the horse’s nostril. This treatment option is FDA approved for equine asthma, and is very safe with no known side effects. This product came to the market in the US in Fall 2020. We have had variable results with this treatmet. Cost for the initial course of treatment (about 12 days) will be around $300-400. Treatment will probably need to repeated somewhere between 1 and 6 weeks after the initial treatment course. The biggest disadvantages are the cost, the need to acclimate the horse to having the device placed in his or her nostril, poor tolerance by some horses who dislike the device, and the uncertainty about how long your horse will be able to go without repeating the treatment.
Option 3 is using a nebulizer with a selection of different drugs and therapies. This option has fewer risks than option 1, has a higher initial cost ($1,000 for the nebulizer mask), but a lower monthly cost (as low as $20-$40/month). Owners using a nebulizer will also have to replace the medication cups on the nebulizer every few months, at a cost of about $80 per cup.
Options for nebulization include the following:
a bronchodilator (albuterol or ipratropium) and a steroid (typically budesonide) - this protocol involves administration of two medications, one after the other, via the nebulizer, once or twice daily. This protocol is lower risk than nebulization of dexamethasone, and relatively inexpensive
Alpha 2 macroglobulin - this protocol involves nebulization of a biologic anti-inflammatory molecule made from the horse’s own blood. Two early studies showed success with this method, in which horses were nebulized every-other-day for one week. Horses then nebulized again if clinical signs returned. Reported lengths of time to needing another treatment varied, with the suggestion that monthly nebulizer treatments may be effective at controlling symptoms. Cost for this therapy as described in the early studies would be about 1,100 for enough product to cover ten total treatments. This protocol may avoid the need to purchase a nebulizer if one is available to rent during your initial treatment phase.
Option 4 is an oral tablet called Apoquel. This is a newer treatment option, and currently the tablets are not FDA approved for horses, only dogs. Like most treatments, this medication will not be successful in every horse, but if it does work, it avoids the risks associated with steroids. Cost is about $10 per day for the first few weeks of treatment, and may decrease to around $5 per day depending on the horse’s response. This medication may be a very good option for minis, since the costs will be much lower. Our success rates have been variable.
Option 5 is shockwave therapy for the lungs. This is a very newly reported treatment, and we have not yet recommended or performed this treatment for asthma. Initially reported data was encouraging, but we will probably hold off on recommending this until we have more information.
DIET AND MANAGEMENT:
1. The Feed: One of the most common recommendations for managing Equine Asthma has always been to stop feeding hay. While this is a very important strategy for some types of Equine Asthma ("classic" RAO), it may not be as important when managing those with Summer-Pasture-Associated disease. I often recommend switching your Asthma horse off of regular hay and trying a period of hay-replacement to see if it helps. Hay replacement consists of any of the following: a complete pelleted diet, soaked alfalfa cubes, hay pellets, or possibly a bagged forage product like Chaffhaye. Once you have the horse's symptoms under control, you can try re-introducing hay. If your horse worsens when hay is re-introduced, you'll need to consider a permanent change to one of the other options!
2: The Barn and Pasture: Horses with Summer-Pasture-Associated disease usually have less symptoms when kept in the barn during the warmer months. Since some horses have both "types" of asthma, you may need to try a stall without bedding, or experiment with different types of bedding. If your horse has "classic" RAO, he may have more difficulty in the barn, and need to be kept outside 24/7.
3: The Supplements: Studies have shown that horses with Asthma benefit from supplements with Omega 3 fatty acids. Look for a supplement with at least 1,500mg of DHA per serving. We recommend Platinum Skin and Allergy or Aleira.
Other Therapy:
So what else can we do for our Equine Asthma patients?
Acupuncture: It appears that some horses with Equine Asthma can benefit from acupuncture to help with breathing function. Typically, a few sessions are required.
Zyrtec: The human antihistamine may be beneficial in a small proportion of horses with Equine Asthma. Since the vast majority of Equine Asthma patients do not have a histamine-associated problem, this isn't likely to work for most. If your horse's test results (from a BAL or tracheal wash) show a certain cell type in the lungs, we may recommend trying Zyrtec!
Clenbuterol: This is a bronchodilator that may be beneficial in treating some horses with Equine Asthma. Clenbuterol dilates the airways, and may improve air flow, but it doesn't treat the inflammation associated with the disease. Clenbuterol should only be used short-term, since it will stop working with long-term administration.