IT WAS all black and white for dairy judges at this year's Royal Melbourne Show.

Holsteins claimed top honours in the interbreed junior, intermediate, senior and supreme exhibit categories.

Leslie Farms, of Arcadia near Shepparton in Victoria, claimed three of the four interbreed awards and the most-successful exhibitor title, after taking home all the champion ribbons in the Holstein section.

Owner Brian Leslie said the stud had "never done better".

The farm's three-year-old cow, Pooley Bridge Bonanza Oak, was crowned supreme exhibit after winning the Holstein intermediate champion and interbreed intermediate champion ribbons.

Sired by a son of two-time International Dairy Week grand champion, Fairvale Jed Bonnie 94, Mr Leslie has high expectations for Bonanza Oak.

"We think she is the best young cow we have bred," he said.

Interbreed judge David Patterson praised the udder attachment and texture of the freshly calved cow.

"The fact that she has only been in a couple of weeks ... she will only get better and better," he said. "Come Dairy Week she will be a heifer to look out for."

Carson Farm Holding's Glenbrae Astound Dolichos was crowned supreme champion Jersey by judge Roger Heath.

Owner Jim Carson from Irrewillipe said the senior champion cow and best vessel winner was the champion dairy cow in southwest Victoria this year, having won more shows in the region than any other cow.

As a four-year-old last year, the cow produced 8000 litres. She runs as part of a 600-cow herd.

For the first time in the senior classes, the Guernsey, Illawarras, Brown Swiss and Ayrshire breeds were judged together in the "combined breeds" competition.

The Cleggett family, from Glencoe in South Australia, and their Guernseys scooped the prize pool.

Lyndon Cleggett and his daughter Amy, with their Brookleigh animals, proudly took home the junior champion heifer, intermediate champion, senior champion cow, reserve senior champion cow, production and type, best vessel, supreme champion and most successful exhibitor awards.

But despite many successes, Mr Cleggett, who has been showing at the Royal Melbourne Show for 20 years, said he never expects to win.

"You never go along with expectations," he said.

"You go feeling (like) the underdog and work hard to do the best you can."

As for Amy it's clear the supreme champion cow, Brookleigh Actions Brunch, is a favourite. "She gets in calf, milks well ... she is a tough cow," she said.