I have a horse work allergies and asthma. Looking at something to help build her immunity up. Ideas?

Excel EQ

CBD! Google "CBD and immune system" for proof

Equinety Horse XL

She is on Equinity. 

My horse used to be so bad with allergies that he always had to be on something and that didnt help much.  and sometimes you couldnt ride him.  I quit bout 4-5 years ago on the rhino/flu shot.  each year he has gotten better and better!  This is the first year I havent had to give him anything for allergies or breathing issues!  When I run I will always use a flair strip for him tho.  The reason I quit the vaccination is bc it seem like within a month (which I gave in spring) he would get bad and sometimes sick! and I would be off all summer!  He hasnt been sick since the first year I quit the vaccination!  and Im shocked bout his allergies! even with his epm flair up his breathing been amazing! and he is happy this summer! I used to dread summers with him! Good luck!  If you are vaccinating Im not saying to quit Im just sharing what worked for us!  Also, had a vet from Texas that told me that if you vaccinate for our area to do around Feb. before the spring attacks their immune system. He said he doesnt believe in vaccinating past being a baby. Very well known vet.

Might not be what you are looking for however my horses issues cleared up by simply removing everything from his diet down to good hay and either something like renew gold or a ration balancer, no traditional grain cut the supplements etc. A huge part of their immune system comes from the gut. I was having to give a lot of meds prior.