TL;DR- sudden onset cough about a month ago. No temp, lungs are clear, steroids didn’t touch it, some improvement on antibiotics but not much. Horse otherwise acting normally.
The long version- While I wait for the vet to schedule a scope appointment, I’d love to hear any possible ideas or experiences that sound similar to what I’m dealing with right now.
My 7yo gelding has a cough. It came on suddenly a month ago. We were doing a conditioning set in the indoor and he started a severe coughing jag. This horse has never coughed in the 3 years I’ve owned him so I quickly cooled him out, got him on the crossties and called the on call vet. He continued to cough - a full body, gaggy sounding cough. His temperature was normal and he was eating, so on call vet recommended keeping an eye on him and having someone put if it continued to be a problem.
I kept him in lighter work thinking maybe it was allergies but his cough got worse so stopped riding him, started him on TriHist on day 9 and the vet came out on day 13 as the TriHist didn’t make any discernible difference. His lungs sounded clear so vet recommended 5 days (with a taper off) of steroids and a 10 day round of SMZs in case it was some sort of infection (still normal temp). When the vet was out 5 days later for barn spring shots, they checked his lungs (still clear) and extended the antibiotics to 14 days given his current condition.
The vet said it was ok to do walk hacks through this as horse does best when in work. The only sort of improvement I saw was on day 18- (6 days after starting antibiotics) he was maybe 50% better. In the days following he seemed to stay at that same level of cough. It was definitely still there but less deep and less frequent; made worse when he’s a heart rate would elevate.
Per the vets instructions, I called after on the last day of the SMZs because his cough was not cured and still a significant problem. The vet came out to do blood work and talk about further options (scoping, lavage etc). Also gave us more antibiotics in case blood work showed an infection. Bloodwork came back clean and now I’m waiting on a scope appointment. Since the blood work on Friday, the horse seems to have declined again and is now coughing in the paddock and on the crossties so I’ve stopped walking him for the time being.
The latest theory (which makes the most sense to me and fits the timeline) is that he inhaled something and it’s stuck somewhere in his upper respiratory system. If nothing is found with this scope they would refer us to Tufts or somewhere for a dynamic scope.
Being a stereotypical adult ammie, I’ve tried to Google and read about the different possibilities but everything I come up with is heaves/RAO/inflammatory lung disease related which doesn’t help because his lungs are clear sounding. So hear I am, writing a novel, in hopes that somebody in here has gone through something similar and might be able to share their experience.
FWIW, horse lives in a field with shelter (so not stalled- the only dust he was regularly exposed to was when we rode in the indoor but that hasn’t been excessively dusty). He has free choice to a round bale but there have been 3 or 4 new bales since this started and neither or his pasture mates have any coughs. He doesn’t have or had any visible injuries on his neck or head indicating he hit it and somehow damaged an internal structure (and this is a horse that gets and shows dings easily so I would expect to see something if he did something like that).
Thought? Advice or soothing words? I just want my boy to feel better 
). The only improvement I noticed was after he was off the dex, day 6 or 7 of the antibiotics.
