After escaping from Horace and Jasper, the Dalmatians get stranded in a snowstorm; they are found by the Collie who leads them to their farm for shelter. They are greeted by the cows who are very kind and motherly to the puppies. When all the puppies become hungry, Duchess is the one to offer them their milk. When the pups feed on her, she assures that there's plenty for all. She then makes a face as if they bit her udders or they sucked on them too hard, but still smiles, calling them darlings. When Perdita thanks them for their help, Duchess shudders at the thought of anyone who would harm the puppies.
Duchess returns in the series as one of the cows who lives on the Dearly Farm, along with Princess. Like Princess, she speaks in a jive type voice; however, she seems calmer in demeanor than Princess.
In "Home is Where the Bark Is", Duchess and Princess are amongst the first animals Cadpig greets; the runt, however, slaps nametags, with simply the word "Cow", on Duchess and Princess' noses. The latter, however, snorts it off. When racing the pups back to the farm, The cows block up the road, causing Cruella to swerve into the Dalmatians' trap. Cadpig later thanks Duchess and Princess for helping her reunite with her family, before reviving the nametag distribution; this time with Princess' name on it.
In "Mooove It On Over", she gets into a quarrel with Duchess about the space in their stall. The two try to make up; however, due to Cadpig intervening, things only get worse. Amongst the insults made, Princess comments on seeing Duchess in a saddle factory, this makes Duchess mad enough to move out of the cow stall and in with the puppies. It is then revealed that Duchess snores while she sleeps, much to the great annoyance of all the Puppies. When Lucky and Rolly attempt to role her over, she accidentally falls down from the loft and on top of Princess, and the two begin arguing again. Within the climax of the conflict, Duchess knocks Princess over, which reveals the paint. Princess uses it to mark their boundaries. When Cadpig stops the fights, the two cows tell the reason they were fighting. Spot then suggests they just open the side of the stall, which Princess comments can work. When the other animals chase Cadpig, for causing the trouble for something so simple, Duchess and Princess ironically comment how they're glad they're not that cranky.
In "Chow About That?", Duchess willingly helps the puppies try to break into the Chow Tower, by being the bass of the Pups catapult. She later sees the pups fly about on a balloon and comments how fun it looks. Princess asks if she's been drinking her own milk again.
In "Every Little Crooked Nanny", Cruella overhears Anita making something for Duchess and Princess. Cruella suspects that Anita is secretly moonlighting for royalty, and when she confronts Anita on this, Anita decides to introduce Cruella to the cows. At first, Cruella bows to them, before realizing to her shock that they're cows that Anita was making winter covers for. When Cruella insults the two, Duchess headbutts Cruella, making her fall in a milk pail.
In "Cupid Pups", Duchess is amongst the first of the animals to question the pups wishing to help Cruella. She later becomes Angelica’s riding animal during the chicken hunt. She flings Angelica in the air when Cadpig tells her to stop.
In "The Fungus Among Us", Duchess is the one who bucks Cruella into the shed, as she finds the field of underground mushrooms. She later tells the Pups what happens to the mushrooms in the afternoon.
At the time of "Prophet and Loss", Duchess celebrates her birthday. She receives a milking stool from Princess and a pail from Cornelia. In the same episode, she also is seen wearing a sun hat and sunglasses.
When Lucky tells a tale about fighting an army of yellow-bellied sapsuckers in "Cruella World", Duchess comments the first time he told it, there was only one sapsucker.
Duchess addresses in "Channels" that she has a cousin called Queenie who lives in the dairy barn down the road. When they’re watching Queenie's award ceremony for "Best Butterfat Performance in a Domestic Dairy", Duchess believes Queenie will give special mention for all the advice she gave. During the same episode, Duchess states a dislike for the program "As the World Churns" calling it "drivel".