I was wondering your opinions on SMZ's for horses with respiratory issues. My horse has been coughing within a minute of loping. It just started this week. The cough is a very deep and only happens when I lope her. My trainer swears that SMZ's will solve this problem. What are your opinions or recommendations? Thank you in advance.

Sounds like your horse has allergy's, I would call my vet and ask him/her..Does your horse have a snotty nose?

Thanks for you input! She does have a small amount of discharge in her nose. :)

if its clear discharge then I'll say allergys, but if the discharge is gross snott they I would think more of a infection going on and then antibiotcs would come in handy. But theres alot of good supplements for allergys out there.

I’ve had several vets say NOOOO.  Bear would be a good one to answer that even though he treats humans.  Bear??

If it's a cough, no runny nose or temperature I'd give him 30cc of yellow mustard once or twice per day for a week and see if that helps. If the mustard doesn't help I'd be going to the vet and have him scoped, do a BAL. upper respiratory infections can turn into pneumonia really quickly so I don't try to second guess I'll if it doesn't easily clear up. 

My mare gets really sensitive and cough. I put her on curost total support and it stops after the second dose. It's expensive but well worth it for me. 

Smz works with bacterial infections. Your situation does not sound infectious, especially if it only happens during the lope. Probably more allergy related. try watering down their hay or talk to your vet.

My gelding has clear runny nose, no cough and seems to struggle to breath when humid.  I am giving him the CurOst Total but it does not seem to help much.  I am thinking it is Heaves.  Any suggestions?

If it's heaves... Hay is 99% the cause. They are allergic to the dust which contains mold and fungal spores. Even the best hay still has them! If you think it's heaves try watering your horses hay. Like I said, Even if there is NO dust there are still mold and fungal spores you cannot see. Watering will allow them to stick to hay so when your horse sticks it's nose in the hay to take a bite they won't breath it in. Something as simple as that makes a difference. If your horse continues to struggle. Hay should be removed and hay cubes or a complete feed should be fed. Steroids only help symptoms... They don't stop the on going damage from inflammation after continuously being fed hay. If you were allergic to bee's you would not sit by a bee hive.  99% of the cause of heaves is like I sais is hay. Best bet is talk to a good internal medicine vet about respiratory not just your average vet.  Heaves is a progressive disease and until you take the allergen away, hay, it will continue to damage your horses lungs and cause a loss of lung function. When someone says my horse has heaves and they are still struggling and they tried everything under the sun... but watering removing or hay... It frustrates me. Because heaves is caused by hay lol. Common sense. Sorry for my rant. After going through it with two of my horses and basically putting their heaves in remission due to pulling hay I get overly Passionate about it. Because who hates not being able to breathe where there is such an easy fix.. no drugs, no supplements.... Just No hay or at least start by watering it.  BUT before all else get the horse scoped and a bal to get a diagnosis.