The two protesters who stormed the stage at Mr. Biden’s rally on Tuesday were identified as Sarah Segal 48, and Ashley Froud, 21, by Direct Action Everywhere in a statement.

“We’re asking him to stand with animal rights advocates, environmental activists and ordinary citizens — and against the inherent violence of the dairy industry,” Ms. Segal said in the statement. Mr. Johnson said she and Ms. Froud were let go after being removed from the stage.

A spokeswoman for Dairy Management Inc., which represents dairy farmers, said on Wednesday that rushing a political candidate onstage was “unsettling and counterproductive to finding shared ground.”

She added that the activists were misrepresenting dairy farming, which she described as “a community comprised of farms of all shapes and sizes that share a commitment to caring for their animals, the land and producing nutritious dairy foods for families worldwide.”

The activist campaign comes as the dairy industry has struggled against many factors, including the rise in dairy-free and plant-based alternatives and a nationwide drop in milk consumption.

And the issue has become more prominent with the backing of the actor Joaquin Phoenix, who provoked the ire of dairy farmers last month when he railed against the industry during the Academy Awards.

“We go into the natural world and plunder it for its resources,” he said as he accepted the Oscar for best actor. “We feel entitled to artificially inseminate a cow and when she gives birth, we steal her baby even though her cries of anguish are unmistakable. And then we take her milk that was intended for her calf and we put it in our coffee and our cereal.”