The Shea family from Bacchus Marsh, Vic, dominated the top awards in the Guernsey ring at International Dairy Week (IDW) on Tuesday.
The family took the grand champion, senior champion and junior champion awards.
The Clarke family's Kookaburra stud from Wallalong, NSW, also shared in the spoils, snaring the intermediate champion, best udder and premier exhibitor award.
Veteran Guernsey breeder Lyndon Cleggett took out the premier breeder award.
The Shea family bought the grand champion First Love Pearly three years ago from Alex and Darien Mathews, Tyson Shea said.
The eight-year-old cow, which was shown under the Sheas' Rockmar stud, had had five calves and was the top producer in the Shea herd, peaking at 50 litres.
Judge Carla Stetzer, of the United States, said the cow "is what a Guernsey cow is supposed to look like; she is a true model of the breed".
In the earlier class judging Ms Stetzer said the cow had "loads of great character" with a great bloom to the udder system.
The Sheas also took out the junior champion award.
The young heifer Endeavour-VP Pilot Delight shown by Tyson and his wife Simone under their Endeavour-VP stud, had earlier won the second class for heifers born between January and June last year.
Mr Shea said the heifer had been stylish from an early age.
It's sire was Pilot and the dam was American Pie.
Judge Ms Stetzer, of the United States, said was a really nice calf with exceptional feet and legs.
"She's so dairy and clean," she said.
Mr Shea said the success of the family was a great reward for all the hard work it put into preparing cows for the show.
"It's like footy - it's something you train for and then you've got to perform," he said.
Guernsey breeding was a family tradition - with three generations having been involved.
The intermediate champion Kookaburra Mark Fate, shown by Daniel Clarke, Kookaburra stud, also took the best udder award.
Judge Ms Stetzer said the Kookaburra Mark Fate was an extreme type of cow with an extreme udder.
"It has a beautiful mammary system with height and width in the rear udder," she said.
Mr Clarke said the win and the supreme exhibitor award made the long trip from NSW worthwhile.
Mr Clarke and his parents milk about 200 cows, with the Guernseys making up about 30 of that number.
So to be able to bring a team of milkers and young calves out of that number and snare the top exhibitor award was a real achievement, he said.
The Guernseys were all "beautiful animals" with great temperament and they also produced A2 milk.
His wife Melissa said the whole family came to IDW.
"It's our holiday - this and the Sydney Royal are the only real holidays we get," she said.
Amy Cleggett, Glencoe, South Australia, whose cow Brookleigh Geo Nell, took the reserve senior champion cow award, said her father's win as the premier breeder was testament to the family's consistent approach.
The sire of the four-year-old cow, Golden J Les George, was named the premier sire.
"Breeding quality cows is great - it's what we aim for," she said.
Grand champion: First Love Pearly, M&R Shea,Bacchus Marsh, Vic.
Senior champion: First Love Pearly.
Reserve: Brookleigh Geo Nell, Amy Cleggett, Glencoe, SA.
Best Udder: Kookaburra Mark Fate, Daniel Clarke, Wallalong, NSW.
Intermediate champion: Kookaburra Mark Fate.
Reserve: Rockmar Miami Graceful, M&R Shea.
Junior champion: Endeavour-VP Pilot Delight, T&S Shea, Bacchus Marsh, Vic.
Reserve: Crookslea Showtime Doreen, N&M Wilkie, Bacchus Marsh.
Premier Sire: Golden J Les George.
Premier Breeder: LF&JM Cleggett, Glencoe, SA.
Premier Exhibitor: Daniel Clark.