Sara Galotiere, ridden by Holland's Sanne Thijssen, suffered a freak accident during Saturday night's four-star international jump-off class at Liverpool Echo Arena.
The horse received immediate expert on-site veterinary assessment and care.
Nina Barbour, president of the Liverpool International Horse Show, said: "We offer our heartfelt and sincere condolences to Sanne, her support team, the Thijssen family and all connections of the horse."