He has topped the Nutritech Performance Awards in Taranaki, run by Holstein Friesian NZ, for the past three years in a row.
This year his business, Buelin Holsteins which he owns with his partner Amanda Linders, clinched the national title.
The awards are calculated using official herd test results and based on the Fonterra milk payment system. In the 2018-19 season, the stud earned $4722.28 per animal.
It also scooped all four categories in the World Wide Sires Protein Awards.
"The secret to having high-producing dairy cows is to ensure your young stock are well grown," Stefan says.
"My heifer calves born last spring already weigh 380kg and they're all sired by the best New Zealand genetics.
"I try to ensure my heifers calve at their mature liveweight. If you want to do serious production the work starts from the day the calf is born," he says.
Buelin Holsteins' 2-year-old heifers averaged 718kgMS in 285 days in the 2019-20 season, according to official herd test results.
A decade ago, Stefan was finding he could not achieve production of more than 500kgMS per cow.
Things began to turn around when he bought a nearby block of land and started grazing his own heifers.
The support block is also used to grow supplementary feed, such as maize and grass silage, which is fed on the dairy farm, in addition to a blend of soya meal, palm kernel expeller (PKE) and distillers' grains.
"Having a runoff is a lot of extra work, but the cost of the feed I produce there doesn't really ever go up, unless interest rates rise," he says
Stefan believes there is less room for error on high-input farms and focused management is essential.
"I'm always learning and it's okay to make mistakes, but it's important to learn from your mistakes and not to repeat them."
His cow Valden Danny Donna-ET S3F GP84 was the overall winner of the World Wide Sires Protein Awards as a 4-year-old, producing 545kg of protein and 515kg of fat.
Average production in the Taranaki region is 394kg of milksolids per cow, according to DairyNZ figures.
Stefan has been looking into using overseas genetics because his options with New Zealand-bred bulls "have been very limited".
