The offspring — named Stumpy High, Pink Bats and James Bond — stem from the frozen semen of Little Yellow Jacket, a three-time world champion Brangus bull.
He has been referred to as "king of the bucking bulls" and "the Michael Jordan of bulls".
The three belong to D&J Bucking Bulls in Clarks Junction, co-owned by Dan Nichol.
Mr Nichol said before Little Yellow Jacket died, straws of semen were taken and frozen using liquid nitrogen.
Those were then implanted into donor cows, who carried out the pregnancy in an otherwise traditional manner.
Bucking bulls were raised exclusively for rodeo, so high kicks and good performing instincts were desirable traits.
When scoring a rodeo, half the points were awarded to the cowboy and half to the bull.
That meant the better the bull, the better the overall score.
There were 34 rodeos across the country and more than 10 throughout the South, he said.
The trio had been to a few rodeos, but were mainly used for breeding.
Some of Little Yellow Jacket’s grandchildren had already joined the herd, he said.
He bought the bulls from a breeder in Rangiora, who had originally imported frozen embryos from the United States, a process which could cost thousands of dollars, he said.
The son of Yellow Jacket and Wrangler Rivets, Little Yellow Jacket was born in 1996. He died September 19, 2011.
The bull won the Professional Bull Riders (PBR) world championship three years in a row, from 2002 to 2004.
He was inducted into the North Dakota Cowboy Hall of Fame in 2006 and posthumously inducted into the Bull Riding Hall of Fame this year.
Little Yellow Jacket was for a time considered the best PBR bull of all time, but was later usurped by Bushwacker.