Deputy Chief Executive at World Horse Welfare, Tony Tyler, has told ITV Daybreak that "having fewer horses at the Grand National would reduce the number of falls."
The first day of the festival was marred on Thursday after a horse died of a suspected heart attack while racing:
Jockey Katie Walsh has paid tribute to her ride Battlefront, who was pulled up on the first day of the Grand National meeting at Aintree and later collapsed and died.
Very sad to lose Battlefront today. We had many great days and he was a great teacher. He was a gent and I will miss him very much!!
Today is Ladies' Day at the Aintree Festival in Sefton, where thousands of women will compete in the fashion stakes.
Aintree is famous for its raceday fashion contest where one lucky racegoer will be selected as the most stylish at the Grand National meeting.
Thousands of people are expected to attend the event over the weekend.
Animal welfare at the Grand National is back under scrutiny after a horse died on the first day of the meeting at Aintree.
Battlefront was pulled up during the fourth race by jockey Katie Walsh and later collapsed and died.
Battlefront had cleared 10 fences in the John Smith's Fox Hunters' Steeple Chase, the first competitive test of significant course changes and new fence frames designed to improve safety.
The cause of his death has not been confirmed but it is thought Battlefront may have suffered a heart attack. A further five horses fell in the race, although none was significantly injured.
Andrew Tyler, director of Animal Aid, said: "The Aintree authorities and the British Horse Racing Authority have been claiming that major new safety measures and efficiencies would eliminate much of the risk associated with racing on the Grand National course.
"But today's Fox Hunters' Chase, in which Battlefront lost his life, was stomach-wrenchingly chaotic from start to finish. Several horses fell or were pulled up, tired and potentially injured.
"It was both utterly depressing and served as confirmation that the Aintree authorities have got it badly wrong once again."
Battlefront was the 23rd horse to die on the Grand National course since 2000, Animal Aid said.
The world's most famous steeplechase is less than 48 hours away.
A staggering two-thirds of us are expected to have a bet on the Grand National this Saturday.
The race meeting started today and our sports reporter David Chisnall has been among the crowds.
The going was a bit soft for riders in this recreation of Saturday's Aintree Grand National!
As thousands arrive on the banks of the Mersey, jet skis dressed as horses took to the waves of the river.
They were racing in the Coral National, a 500 metre race on the River Mersey in Liverpool.
The 'jockeys' wore the colours of the real riders who'll battle it out in the world's greatest steeplechase this weekend.
Organisers are expecting record crowds at this year's Grand National meeting starting today.
Officials at the world -famous Aintree course say it is now safer than ever for the horses.
New plastic frames for some fences pose less danger following the deaths of two horses last year.
The starting post has also been moved 90 yards.
Animal Rights campaigners have long demonstrated against the steeplechase.