"For a cow of this age she's in phenomenal form," juror Klaus-Dieter Augustin said.
Gaga beat around 200 competitors from all over Germany and Luxemburg to take the coveted ribbon and be known as "Grand Champion" for the coming two years.
"I bought Lady Gaga three years ago, I have no idea why the previous owner gave her that name," owner Henrik Wille from Lower Saxony told The Local on Friday.
Wille keeps Gaga and two other prize contenders in a private box back on the farm so that she won't be injured by other cows.
"They live together, they won't do anything to each other. We keep them separate from the others so they stay thin and pretty and take them down to the pasture separately.
"I have some very nice, beautiful 'normal' dairy cows who produce milk, but none of them are like her."
Gaga – like many other prize contenders – travels with her own stylist, making backstage before the show a riot of hair trimming, shampoo foam and sweeping brushes.
She had to show off some fancy footwork while running several laps of a paddock before lining up in a row to impress the jury – and 5,000 spectators in Oldenburg's EWE Arena.
But it's all in a day's work for bovine top models like Lady Gaga, whose strong legs, well-formed udders and top-notch phsyique carried her to victory.
The four-legged beauty has been showered with prizes at recent shows, making her a shoo-in for the title among Germany's roughly 2.6 million Holstein dairy cows.
Wille says that the win will be "good advertising for my business.
"If people see that I have good cows, they'll come to me to buy young ones," he added.
Lady Gaga has her own page on his website listing all the awards she's won.
But the dairy farmer was also keen to point out that now she's famous, Lady Gaga can have a teaching role too.
"If anyone wants to come and see her, they're more than welcome," he said. "I have school classes visit sometimes and they can come and interact with the cows, stroke them and so on," he said.
To celebrate her big day, Lady Gaga will be milked and washed before tucking into an extra portion of hay, Wille said.