Judges say cowboy Tuf Cooper, who is from Decatur, Texas, aggressively whipped his horse with a rope during the tie-down event Wednesday afternoon.
Stampede spokeswoman Kristina Barnes says it's believed to be the first ruling of its kind at the competition.
She says using a rope as punishment or correction is unacceptable under the Stampede’s animal care protocols.
Cooper's agent, Shawn Wiese, says his client accepts the Stampede's decision and doesn't question it.
Wiese says Cooper has high regard for his horses and would never intentionally hurt an animal.
CTV Calgary said it received a statement Thursday from a member of Cooper's team defending the cowboy's actions.
"Tuf's horse was late coming out of the box," said the statement. "Just like a barrel racer whips her horse home to the finish line or a chuck racer whips their horses to the finish line, Tuf had to get his horse to catch up to the calf.
"The decision of the Calgary judges comes from a long fight with animal activists that want to get rid of calf roping altogether. If the Calgary Stampede keeps making rules up as they go to please animal activists, there will be no Stampede in years to come."
According to the Stampede's website, in the tie-down event, cowboys must rope a calf and tie three of its legs while his horse keeps the rope taught.
Cooper, 25, had been the 2011 Calgary Stampede tie-down roping champion.
Earlier this week, a national animal-rights organization called Animal Justice called on the Calgary Humane Society to prosecute "inhumane rodeo practices" at the Calgary Stampede.
The group said more than 50 horses have been killed during chuckwagon races alone at the Stampede since 1986.
So far this year two horses have been euthanized as the result of injuries suffered during the chuckwagon competition.
The Stampede's Chuckwagon Safety Commission called the deaths "extremely regrettable" and said the Stampede is working to ensure the focus of the drivers "is running a safe, clean race."
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