Queensland apprentice Ruby Ride has been taken to hospital for assessment after her mount Red Magic crashed through the fence at the 250m mark in a 1200m-race at Doomben.

Ride had pulled Red Magic to the outside to make a run in the straight in Wednesday's race when the gelding began to wobble and careered back to the fence and crashed through out.

Red Magic and Ride lay motionless on the track as officials raced to help them.

Ride was treated on the track for 25 minutes before being loaded into the ambulance and taken to hospital.

Chairman of stewards Martin Knibbs said Red Magic had bled badly and had been euthanised.

"Ruby was conscious and complaining of some pain in her back and buttocks. But she will have a complete tests at the hospital," Knibbs said.

The remaining two races were put back while another ambulance was sent to the track.

Ride is one of Queensland's most promising apprentices but her career has been dogged by injury.