Mr Child and Dice came first in the long head with 192.75 points.
It was Mr Child's 29th New Zealand or island placing, including his other national title a few years ago in the zigzag hunt, but last week's win felt particularly "special", he said.
"It's a hard hill to head and the sheep have been difficult at times, but it was a good run-off and strong competition," he said.
"To win was a great pleasure."
While Dice was only 2 years old, she had good genes behind her.
Her father, Deal, previously won the New Zealand title in the same event and had sired three New Zealand winners.
"We hope she's got a big future."
Raetihi triallist Bruce Parkinson and Brook won the short head and yard with 194.5 points.
Mr Parkinson could not remember how many New Zealand championships he had contested but said there had been "a few".
His other national title came in 2000, when he won the straight hunt event.
Brook finished second in the last two national championships in the short head and yard and the long head.
Mr Parkinson had competed at Alpha Burn Station before but then "we went home with our tail between our legs ... we made up for it this time," he said.
Representatives from the regional and national sheep dog trial bodies were thrilled with this year's championships, which had attracted record entries of around 300 competitors.
Otago Sheep Dog Trial Centre secretary Alistair King described it as a "roaring success", particularly in terms of the more family-oriented atmosphere this year, which he attributed to organisers moving the event to coincide with Queen's Birthday weekend.
New Zealand Sheep Dog Trial Association vice-president Graham White said feedback from competitors had been very positive.
"One or two old seasoned campaigners ... they reckon it's been one of the best championships they've been to," Mr White said.
The layout of the courses, all in close proximity to each other, had been well received, as had the spectacular scenery at Alpha Burn Station.
"The cameras were going flat out from the North Island people."
The national association's president John Harvey said the McRae family, of Alpha Burn Station, had been integral to the event's success.
"It's a huge, huge ask for any landowner to have the trials on their land ... and they've just been magnificent, they really have been.
"It's just made the whole thing go off so well."
