My boy has a bad dust allergy and before shows I give him a little Benilyn (dry cough formula) in his breakfast so people don't give us looks like I've brought a diseased pony near theirs! L
I know loads of people who use it, but A WORD OF WARNING!
My friend gave 2 spoonfuls to her ISH and within 15mins he was going absolutely loopy in his stable, literally climbing the walls, he was shaking and didn't know what to do with himself. Ended up having to get the vet out to give him some sedative and just wait it out until it was out of his system. Vet said he had seen it happen once before but that most horses were fine on it.
I'd maybe just try a bit to check he doesn't have an adverse reactions, after witnessing this incident I'm a bit weary as it was awful to see.
Personally would be more inclined to find the cause of cough and treat with suitable antibiotics etc.
I do know that Martin Pipe used to use Benilyn on his horses regularly. No idea if this still happens or if it shows on a dope test!
I have been using benilyn (she hates actifed) for years on one of my horses and she gets chesty coughs, i get the one for chesty coughs and syringe down the back of her throat.
It works brill with her but always try a small amount as even people can have a reaction for cough mixture.
OH assures me that his mum used to make him use horse benelyn when he got a cough as a nipper - she used to get it from a racing yard. Can't you still get it?
Used it on Bobby last year when the field was incredibly dusty & being the smallest old one he seemed to keep getting left behind with dust in his face when they all went off on a mad moment. Gave it to him in a sandwich, he loved it. Best bit was asking the pharmacist what the correct dose for a 13.2 was!!
I use simple linctus - 99p a bottle from most supermarkets. The horses all love it and it can be added to pure glycerine BP and syringed down. Tastes yummy.
I always use Glycerin and Lemon (Buttercup Syrup) added to feed as it has no active ingredients so is very safe to use. Always does the trick if ever I have some hay which is a little dusty and causes my boy to have the odd cough. Sorts it out next day.