The 81st running of the Canadian Derby took a scary turn on Saturday after three horses went down on the race track, rattling their riders.

The incident started in the last half of the competition when Anthony Selgado fell over the top of his horse. Jockeys Mario Gutierrez and Eddie Martin Junior could not avoid the fallen rider and also hit the ground.

While Selgado and Gutierrez initially appeared to be in rough shape, CTV News is told that save for some bruises, they are fine.

"They've all come out of the medical tent - they're okay," said John Huntington, an official with Northlands Park.

Those who watched the incident unfold still aren't sure what triggered the crash.

"Looks like he got a little tight or the horse maybe come up and clipped heels on the one in front of 'em," said trainer Jim Meyaard.

"We won't know until we look but anytime this happens it isn't good."

The thoroughbreds involved in the incident – Dyna Stroll, Stachys and Alberta-bred Professor Pollard – are all said to be in good condition.

With Files from Natasha Staniszewski