Racing at Great Yarmouth was abandoned after three races on Monday because of concerns over the condition of a patch of ground following a serious fall.
Jockey Gabriele Malune was catapulted into the turf as his mount Lord Chapelfield broke down.
Malune was attended to on the track for some time following the third race, before being taken to hospital for further assessment.
The horse, trained by Amy Murphy, was fatally injured.
A deputation of jockeys subsequently inspected the ground with officials, including clerk of the course Richard Aldous.
“The jockeys were concerned about the mark the horse made when he fell. They felt the course wasn’t fit in their opinion. You have got to respect their opinion as they are the ones riding on it,” said Aldous.
“We will have a further look at the course this evening and tomorrow to see where we are at ahead of the meeting scheduled to take place on Friday.
“I think it was a unanimous decision by the jockeys and you have to respect that. It was terrible to see. Gabriele has gone to the James Paget Hospital in Gorleston for further assessment. He was awake and talking upon leaving the track.”
Newmarket trainer Murphy said: “It is horrible. Gabriele is my apprentice and we have lost a horse, so it is devastating.”