My horse was diagnosed with COPD over 5 years ago. I just wanted to give you some words of encouragement that things are not always doom and gloom and although COPD is not curable, the prognosis really depends on several things. The first two years were rough for my guy and I was disheartened that he may not be able to perform at the level he was at before. However, with situational changes and management, he has improved heaps since then. His COPD is barely recognizable now and really has only affected him on very hot days. He has not been maintained on medication, although I do keep some on hand for emergency. Here is my advice if you are interested:
I recommend this website for a good overview: https://equinemedsurg.com/pages/in-d...ne-heaves-copd
First, to deal with respiratory attacks. I recommend buying some medication to have on hand, in case of a respiratory attack. There are several different types and they all have pros and cons. Talk with your vet to see what they think would be best. For example, dexamethasone is not usually the best option for horses with metabolic issues, nor horses with Ulcers. I also recommend making or investing in a aerosol with bronchodilator. They are a good tool to have on hand. Also, expect symptoms to be prominent or even worsen the first few years. It will take time for your horse to build his immunity back, and that is with the right conditions. You will also be learning how to manage it. During the first few years and every so often in subsequent years, I actually took TPR measurements and wrote down any observations to see if I could find any patterns. Now, obviously this isn't necessary, just the nerd in me, but I did learn exactly when my horse was most vulnerable for a respiratory attack. I found he was more likely to have breathing issues during transitional weather periods, when we was unfit and after vaccinations. I was also able to see his average respiration gradually declining. It was initially around the 30s, then low 20s, etc...now It is 16 or lower on average.
My horse has actually never been maintained on medication, besides the period following diagnosis and in flare ups. A lot of this has to do with the fact that we caught it earlier and immediately made management changes as soon as possible. I also went down a rabbit hole of reading a ton of research articles and chatted up a few vets when he was first diagnosed and slowly made changes according to see what would work, and it seems it may have. Long term medication, while necessary in some situations and in flare ups, can also be harmful to prognosis. Long term corticosteroids, such as dex can impair the adrenal cortex's ability to keep up with natural cortisol demands. So, you have two competing systems: dex, the synthetic corticosteroid that is at a much higher level ideal for quicker action in inflammation reduction and (2) the body's naturally produced cortisol, which eventually can't be sustained to the levels of the drug and hence the body's ability to naturally combat inflammation becomes faulty. Thus, the result of long term drug use can actually cause dependence of the drug.
I also ended up modifying his diet so that it was centered on reducing inflammation. First, was optimizing Omega 3 to Omega 6 ratios. Omega 6 is plentiful in most commercial grains and actually has a pro-inflammatory effect when higher than Omega-3, which is found in fewer feeds. Increasing Omega-3 relative to Omega-6 helps the body deal with inflammation. Cereal grains, such as corn and oats, along with sunflower and safflower seeds contain much higher levels of Omega-6, as do many Oils. Flax seed is one oil that is actually good in its Omega 3 content and there have been a few studies on flax supplementation on COPD horses, so I had added 1/4 cup of seed per day. I also added things such as MSM (20,000mg) , which was recommended by my vet. Tried some joint supplements and Vitamin E, etc. I had also used Omega Alpha Respirfree when needed.
Exercise is also beneficial to help bring up mucous and condition the lungs. I definitely noticed a difference when my horse was unfit and FAT, which is just extra weight on his lungs. My barn owner's 20 year old has advanced COPD and the one thing that has kept her going is the consistent exercise, which the vet also recommended to her at the time. There are also some studies showing some improvement in COPD with consistent exercise. There is a fine line though, as you wouldn't want to work the horse during a respiratory attack. However, a few minutes of trot could also help open the airways before he worsens.
Additionally, good hay is a must! We actually haven't soaked his, but I had moved him to a barn where there was very good quality square bales. I've been pretty adamant on not feeding round bales, especially when he was at his worst. I might be more open to round bales now that he is at a better point, but no free feeding from one for two reasons: (1) feeding directly from the round bale exposes him to more spores and (2) typically it is easier for mold to go undetected in a round bale vs square bale. He has been eating hay from the ground for this reason. Any scenario involving him shoving his nose into a big bin of hay or roundbale, and well he is a foodie that will not move until all is gone....anyways, it usually makes his breathing rate go up. The big thing is keeping dust down.
There could also be specific allergies involved that you'll find later or even the air quality, spores etc. My vet used to deal with a COPD horse that was always flaring up. Well, he was sold to a different area and apparently all the issues went away.