Mr Gregory (19), of Gore, was named supreme champion junior judge of the sheepmeat breeds judging competition run by the Royal Agricultural Society of New Zealand, and the Federal Council of Agricultural Societies of Australia at the Manawatu A&P Show in Feilding last month.
One of seven similar competitions between Australian competitors representing each state, the section included judging a group of Perendale and Southdown ewe hoggets, with the young judges then explaining their rankings and reasons to the overall judge and the crowd.
Other competitions included dairy and dairy handlers, beef and beef handlers, merino sheep, wool and the Young Ambassador.
Mr Gregory is due to start his second year at Lincoln University where he is studying towards a bachelor of commerce (agriculture) degree. A career in rural banking was a possibility, he said.
He got involved in stock judging during his final year at St Peter's College in Gore. He also competed in the Otago-Southland TeenAg regional competitions in 2011 and 2012, both times making it through to the grand final, placing first in 2011 and second in 2012.
He was selected to represent New Zealand after winning a similar competition at the Royal Show in Hamilton following selection at a regional judging day held by the Gore A&P Association.
His mother, Janet, is a member of the Gore A&P show committee which runs the judging school.
It was a great way for young people to learn about judging different types of animals, breed traits and what to look for in animals, as well as gaining confidence in public speaking and handling the stock, Mrs Gregory said.
They gained points for getting the stock in the right order, their own presentation, and the reasons they gave for placing them in that order.
Gore A&P held a regular training day in April which included dairy cows, beef cattle, horses, and both meat and wool breeds of sheep.
Mr Gregory said it was great to win for New Zealand, which took the shield for most points against the Australian states.
He enjoyed stock judging, saying he learned something new every time, as each judge was looking for different things.
''You can build a good image from heaps of different people about what you want to be looking for,'' he said.
It also gave him exposure to breeds with which he was less familiar.
While delighted with his success, he believed he could have done better: ''I wasn't that pleased with my performance; there's plenty to work on.''
While he could not progress any further with judging sheep stock, he was keen to get into judging beef cattle.
He had a strong interest in stud stock and he enjoyed his involvement with Waikaka stud breeder Rob Hall and helping him with his beef cattle.
During the university holidays, he was enjoying working on a hill country property near Cheviot in North Canterbury.