Bleeding from the lungs is common in racehorses, where high blood flow rates are essential to deliver oxygen to rapidly contracting muscles.

The pressures generated by this blood flow in the small, thin-walled pulmonary arteries result in rupture and haemorrhage.

“Horses that bleed on the track often do not bleed again when they finish racing. The exertion their lungs are placed under in any discipline outside of racing will be nothing compared to what they were used to before,” says Caroline George MRCVS from Lambourne Equine Vets, who has an ex-racehorse of her own that she hopes to event next season.

The 1995 Cheltenham Gold Cup winner Master Oats suffered from EIPH, but that didn’t stop him going on to hunt with the Heythrop well into his 20s.

For the full veterinary article on health management for ex-racehorses, see the current issue of Horse & Hound (29 September, 2011)