Sea Of Class, is fighting for her life after suffering a career-ending bout of colic.
She is receiving intensive care after an operation on Wednesday.
Her trainer William Haggas told the Racing Post on Sunday morning: "It is with great regret that I have to announce that Sea Of Class underwent a colic operation on Wednesday, which will end her racing career.
"At the moment she is at the vets and receiving intensive care and is doing everything as well as can be expected."