The Aintree Festival was plunged into more grief on Friday following the death of another horse over the fences used in the Grand National Steeplechase.

Little Josh was euthanased after breaking a shoulder following a heavy fall in the Topham Steeplechase, the fourth race of the day. He was the second horse to die at this year's festival.

"This injury was not treatable and it was the necessary course of action," Professor Chris Proudman, veterinary advisor at Aintree, said.

It is a major blow to organisers who were hoping for an incident-free festival after making modifications to the course in the wake of four deaths in the past two Grand Nationals and complaints from animal rights groups.

"We have made significant improvements in safety at the course, but we also recognise that jump racing carries risk you can never completely remove from the sport," Aintree boss John Baker said.

Jockey Liam Treadwell was hospitalised after falling from Regal d'Estruval in the same race.

Jockeys have largely approved of Aintree's restyled fences, which have been softened by removing wooden stakes and replacing them with a more forgiving plastic material.

Critics believe still more needs to be done, with 21 horses having now died in races over Grand National fences since 2001.

"Sadly there is a statistical probability that horses will die at the Grand National meeting," said Dr. Mark Kennedy, head of science at the World Society for the Protection of Animals.

Nigel Twiston-Davies, the trainer of Little Josh, said the horse had "gone out doing what he loved most".

"It could happen anywhere, it could happen at home and it's not the fences. It could have happened at a park course," Twiston-Davies said.

Barely 30 minutes earlier, Sprinter Sacre had provided another demonstration of his class by sauntering to victory over a top-class field in the Melling Chase, taking his unbeaten run over fences to nine.