Long-time exhibitors Philippa and Mark Flemming, Philmar Dairy Co, Tocumwal, NSW, took the junior interbreed award at International Dairy Week.
Miami Magnify Dawn 5206 took the Royal Agricultural Society of Victoria interbreed champion award ahead of the Illawarra heifer shown by Brad and Jessica Gavenlock.
The Flemmings son Mitchell, who is also involved in the family business and is responsible for preparing the show cows, said the win was "awesome".
It was a great reward for the hard work.
Mrs Flemming said earlier in the week when the heifer won the Jersey junior championship that it was the first time the stud had won a championship at IDW.
The calf was from a home-bred bull the Flemmings bought from a farm at Tamworth, NSW, they visited as part of a farm inspection tour at a Jersey Australia forum.
Mrs Flemming said the bull was from the Magnify family Philmar had bred 28 years ago.
The bull was run with the heifers after they had been artificially inseminated and this was one of its first daughters.
"We use a lot of AI, so to get one (a champion) from a home-bred bull is unusual," she said.
Philmar has a 600-cow split-calving herd.
Show cows and embryo transfer donors were run separately from the main herd from September.
Mitchell is also a cattle fitter and worked on preparing the cows.
Mrs Flemming said livestock sales accounted for about 20 per cent of their operation's income with Philmar raising every heifer it breeds.
Showing helped build their profile.
"Other stud breeders buy lines of cows from us," she said.
Jersey judge Mr Lahmers said he loved this great heifer, particularly its straightness of line.