The estate of a prominent breeder who insisted the show go on for the benefit of riders has made the largest-ever bequest to the National Jockeys Trust.

The $400,000 donation, announced on Saturday, came from proceeds of Denise Cobcroft's stud, which has continued operating since her death in 2010.

The donation is the largest from an individual, fundraiser or bequest in the NJT's 13-year history.

"It was Denise's desire that the money should benefit injured jockeys so it gives the trustees great satisfaction to have been able to fulfil the wishes of this beautiful friend," Cobcroft trustee Bob Charley said.

Breeders Classic winner In Her Time and last year's Stradbroke Handicap winner Under the Louvre are among the stakes winners bred by the Cobcroft estate.

The daughter of a Hollywood actor worked on stage in London, New York, Paris and New Zealand before meeting polo player John Comcroft at a horse show in 1966.

"Denise Cobcroft certainly was one of a kind and the National Jockeys Trust will remember her that way," the NJT said in a statement.