I bought the large dog version for Andre (it is an inch shorter than the horse version) and he hates it; he tries to bite and acts like it's going to kill him. Hasten to add that I've gone back to using a rubber curry comb and shedding blade! No-one else seems to have this problem with them though, I obviously have a rather sensitive neddy
I have the large dog version for my large dog, he hates it too! I think it's the shh, shh noise it makes when you groom with it. Does it make the same noise on a horses coat?