hello, I had a horse years ago, a dapple grey arab/welsh gelding. he was fine till we got a load of clover hay or some with more frequent clover. we had 4 horses at the time and he developed a cough and grew to the point of nonriding. the vet said originally it was an aggravation and we should seperate his feed, wet his hay, etc. We did what we could. I think I read later that dapple greys can be prone. not sure if that's fact. none of our other horses had anything near what he developed.
coincidently, recently, I bought my neices walker/paint he had a cough, or developed one. I've only owned him for several months. again (history repeats) we have another mare and two ponies and they have virtually no symptoms of cough. he got a one-tub steady of Equihist granules when she owned him, shortly before I bought him. I think it was end of year last year. It seems to have subsided, but I ride him more and he does have some bouts that come and go.
I think the Equihist is an antihistamine. my aunt (owns the mare) thinks a good burst, then back off and let his immune build up?? wet the hay down. I've thought of the herbals, but I'm apprehensive. I'm playing it by ear. My paint/walker is a bit underworked, I think he may get stronger. I'm hoping. I was on here looking for info on heaves. I think he may have that and not emphysema. the dapple grey was diagnosed eventually with emphysema. I've used some vitamin/mineral supplements.
I welcome any comments from the experts here.