Has anyone encountered this issue with their horse? My Cleveland bay gelding on occasion falls asleep while on cross-ties. Can happen while he is being groomed or while he is simply standing. His knees buckle and he collapses as far as the cross-ties will hold him. He's done it a couple of times and caught him once while he was standing in his paddock..... Any thoughts on this and what to do to correct the problem would be appreciated. Hopefully this is not a narcolepsy issue!