When I first ask for a trot he will pick it up right away but after a minute or two he begins to cough. I usually let him walk and he will cough 7-8 times then he is fine for the whole rest of the ride. He only coughs the first time I trot at the beginning of the ride. After that we could trot around all day and he won't have that issue again. Normally I wouldn't worry too much but I have worked with a few horses (not a ton) but a few and never had one do that before.
I was just wondering if it was something I should be especially concerned with? Do I need the vet to come out?