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The Grand National steeplechase was marred for the second year in a row with the death of two horses Saturday, including the pre-race favorite Synchronised.

Synchronised went down at the sixth fence of the 4½-mile, 30-fence race considered one of the world's most prestigious jumping races. According to Pete went down at the same fence, but later in the race.

The start was delayed when Synchronised unseated jockey Tony McCoy, but race organizers said the horse was "thoroughly checked" by a veterinarian and allowed to line up in the 40-horse field.

Neptune Collonges, a 33-1 long shot, won in the closest finish in the history of the race, which drew a crowd of 70,441.

"In both cases the horse incurred a fracture to the leg and the humane option was to put the injured horses down," said Tim Morris of the British Horseracing Authority. "The Grand National undoubtedly represents a challenge to both horse and rider.

"It has inherent risks, but, working closely with Aintree and other stakeholders, we do all we can to minimize these risks while maintaining the unique character of the race."

There was no immediate word on injuries to McCoy or Harry Haynes, who was aboard According to Pete.

Morris said the BHA's objective is to reduce the number of injuries and fatalities in racing.

"We will examine closely the circumstances which led to both incidents ... and consider what measures can be taken to address the risk of a repeat in the future," he said.

After two horses died in last year's Grand National, organizers responded to criticism from animal rights groups by altering the course.

"We are desperately sad at these two accidents and our sympathies are with the connections of both horses," Aintree managing director Julian Thick said in a statement.

Despite the drop at Becher's Brook — one of several fences noted for their severity — having been reduced several inches, that was where both horses fell.

"I am not happy about drop fences and Becher's is a drop fence," said David Muir of the Royal Society for the Prevention of Cruelty to Animals. "Before the race I said let's see how horses cope (with modifications made since last year) and it appears they still had difficulties coping with that fence, but it is a work in progress."

"After today, we will, as always, be looking at all aspects of this year's race to see how we can improve safety further," Thick said.

"Since last year's race we have made further significant changes to the course and there have been four races run over the course without serious incident since then," Thick said. "After today, we will, as always, be looking at all aspects of this year's race to see how we can improve safety further."

Trainer Paul Nicholls, who won the National for the first time with Neptune Collonges, said risks come with racing.

"When you are in competitive sport, whatever you do, motor racing, hockey there is an element of risk," Nicholls told the BBC. "The worst thing you can do is to go too far. You make the fences smaller, they go faster and you get more fallers.

"Sport is risk. We have to live with that and get on with it. We have to grow up, basically. A lot of people have to grow up, and realize that it is life, and get on with it."

The death revived memories for winning owner John Hales of his horse, One Man, dying in a fall during the 1998 Aintree Festival.

"It split the family coming here," Hales said. "My wife was 50-50, my daughter couldn't face it. She has gone show jumping and is overcome with emotion."

Hales said Neptune Collonges would be retired after coming from behind to beat Sunnyhillboy in a photo finish. The horse, ridden by Daryl Jacob, became the first gray National winner since Nicolaus Silver in 1961.