We saved a horse in very poor condition that was treated pretty badly. He is now up to good weight and fighting fit but we have had him diagnosed with something called a roar (scientific term is laryngeal larynx) , the condition involving larynx dysfunction can severely compromise a horse's ability to breathe, especially during exercise. The problem often is first discovered in growing horses. There is no cure other than this operation. He is 6 and has his hole life ahead of him. Be lovely to see him galloping freely.