Animal welfare groups have called for an outright ban on the Grand National following the deaths of two horses in Saturday's race.
The animals were killed during the first circuit of the gruelling four-and-a-half-mile course.
Ornais fell at the fourth and Dooneys Gate fell at the sixth, Becher's Brook. Only 19 of the 40 starters finished.
The latest deaths have prompted campaigners to call for an end to the historic race.
Animal Aid director Andrew Tyler said: "The Grand National should be banned. It's a deliberately hazardous, challenging and predictably lethal event."
He said the race's combination of a tightly packed field, high fences, long distance and huge crowd noise meant it was extremely dangerous for the horses taking part.
The League Against Cruel Sports said there had been 17 deaths at the National in the past 16 years.
Julian Thick, managing director of Aintree Racecourse, said: "When a horse gets hurt, everyone is deeply upset. We will redouble our efforts to make sure that everyone involved in the event is able to participate in safety."