Each square is numbered and the square with the most cow poo is crowned the winner - a surveyor works out the square electronically, so no need for markings on the grass.
When I first heard this was taking place I thought whoever signed off on the idea was mad, however, it turned out to be a real winner.
Yesterday marked the 21st running of the cow dump at the school, with the event raising anywhere between $8000 and $12,000 each year, Cathy Charmichael said.
However, it was also the final bell for principal Brian Field who is retiring at the end of the school term after 26 years at the helm.
"It brings the whole community together," he told the Bay of Plenty Times.
"Heaps of people have been coming here for years. Some of the parents were students themselves when we started."
One focal point was a catapult created by John Charmichael which was used to launch lollies into the air, making for an especially interesting lolly scramble.
She spent her time walking around her makeshift paddock on the school's sports field.
Over the years, the Charmichaels have used three different cows.
"The dump has always been before 2pm," John said. "Daisy has been the best-behaved of the lot, she doesn't have a care in the world."
And after a short feed of hay, Daisy performed her duties well ahead of schedule, going to the toilet at exactly 11.40am right in front of Field.
"I've never seen that before. I've never been here for that," he laughed.
Field thought around $30,000 would be generated by the cow dump and the gala events, which would be used towards providing shade for four new playgrounds.