Respiratory supplements...? do they actually make a difference?

[Lynsey88]

My horse always coughs 2 or 3 times when first warming up, usually once we start trot work. Once he's warmed up he is usually fine but the other day he has a coughing fit half way through a dressage test! i think this was because i hadn't warmed him up properly! it doesn't seem to bother him much and he has always done it as if to clear his throat before he works, and doesn't effect him at hard work in any way. But when warming up at competitions i get some funny looks as if my horses is going to drop dead!! :/
I thought it was his hay, even when soaked but he's now on just grass and its still not changed
I am considering putting him on a respiratory supplement and wondered what peopled experiences of using these are? do they actually work? and which ones do u recommend (on a budget!) ?

thanks!

 

[dotty1]

My four year old started coughing a couple of weeks ago, as soon as I got on her she had a deep dry cough which went on for a while followed by lots of snorting. I bought some Carl Hester Air Power liquid after reading some reviews. She wasn't keen as it does smell strongly like 'vick' but it does seem to have worked and yesterday there was no coughing, today just a couple when we started off.
I got is from www.thomasirving.co.uk as it came with a free pot of nasal stuff (just like vick). It came next day.