From 1986 to the present over 50 horses have died in chuckwagon races at the Calgary Stampede.  Another 17 have died in non-chuckwagon incidents, such as cattle penning or bucking events

Two have died in the past four days.

These animals suffered before dying or being euthanized. They have died from injuries, heart attacks, a burst lung artery and more.

Ten calves have had to be euthanized over the same period after suffering broken legs during roping events.

Two people have also died but the difference there is that the people had a choice.  They chose to risk their lives (and their animals) for the sake of entertainment and bragging rights.

The chuckwagon races must be stopped so no more horses die in agony.

The photo is from dailymail.co.uk.  Note the third horse behind the others and the man lying on the ground in front of the horses.