airway inflammation allergies ambassador ammonia behaviour breathing breathless colic comfortstall dressage EGUS elderly equine asthma equine behaviour equine health Equine nutrition eventing fatigue feed feeding foals forage forager geriatric grazing hay steaming hay storage Haygain horse coughing hydration IAD joint health laminitis nasal discharge nutrition owner testimonial palatability performance physiotherapy professional groom professional rider rehabilitation centre research respiratory disease respiratory health review rider review rubber matting senior skin conditions slow feeding soaked hay soaking hay stable flooring stabling steamed hay testimonial top tips veterinarian WEG winter