A young boy who was attacked by a 500kg cow in Geraldine was watching his sister compete in a local adventure race.
A Canterbury West Coast Air Rescue spokesman said the 7-year-old was with his family on Sunday when the cow jumped the fence and stomped on him.
The boy suffered abdominal injuries and fractured ribs and was flown to Christchurch Hospital, the spokesman said.
The Geraldine Adventure Race took place on private land on Waihi Gorge Rd in Woodbury.
An event competitor told Newstalk ZB the boy was attacked while watching his older sister compete.
The person said livestock was moved prior to the race and that a farmer had warned competitors of a "mad cow".
They are concerned the attack will look bad for the family who own the property, and that they may not open it up again in future.