Well, obviously, Janice you are right about there being something wrong with this horse. Was there water on the trail? Was he dehydrated? You can take a pinch of skin and see how long it tents and check for anal tone.
His heart rate of 120 doesn't scare me too much, since we back off at 200, but it's probably pretty high if he was at rest. He should recover to around 60 in ten to twenty minutes. We aren't allowed to continue on if they don't recover to 60 bpm in thirty minutes. The respirations are of great concern. Horses do die. There's a rider (an RN) whose horse went down just before the vet check at a ride last year. She was totally freaked. I heard later that the horse survived, but unless there was an underlying health problem, this is rider error. Another thought ... one of the first horses I bought had what they then called "heaves". I think it's actually emphysema and usually caused by feeding moldy hay. At least that was what we were told 40 years ago. Nancy
