People spent hours with a shovel, wheelbarrow or a rake performing the tedious task, he said.
Mr Young is at Horse of the Year as the New Zealand SuperScooper distributor.
The idea is simple: you just attach the scooper to the back of a mower or quad bike, drive over the manure and it is scooped inside. The scooper is then flipped, transforming it into a trailer to take the poo away.
The product was a winning invention on Australian TV show New Inventors in 2008.
Mr Young hoped the device would make life easier for other horse owners.
"I was talking to a woman while her husband tested out the machine - I then noticed she was crying," he said. "I asked her why and she said the machine was going to change her life."
The Cleveland woman had 10 horses on four hectares (10 acres). She was getting up at five in the morning to pick up poo, stopping only to cook her family meals.
"That was her life."
This year marks the seventh Horse of the Year show for Mr Young. His highlight is the Olympic Cup, which takes place on Sunday.
"It's a fantastic atmosphere. The grandstand is absolutely packed with people."
He said that unlike other sporting events, the 15,000 people watching stayed silent during competition but as soon as the rider was finished, the crowd erupted.
"It really is amazing to see."