The practice is pretty common - and it has been for years, according to Gene Baur, cofounder and president of Farm Sanctuary.
"It's just another example of these animals seen as milk machines instead of living creatures," Baur told The Dodo. "When you're burning udders, there can be pain. They say they're doing it quickly, but accidents can happen."
Cows are also very social creatures; they have emotional lives comparable to other mammals, even dogs. So the idea that cows are confined in milking pens while a sudden flame is passed under them is just another thing about massive dairy industry practices that can be hard to stomach.
"Cows, like all animals, are social creatures, and they're very much influenced by their social environment," Baur said. "Burning the udders is just another example of how these animals are disrespected."
Baur added that treating farm animals as just production units isn't good for anyone. "It creates a whole feeling of stress and anxiety and discord," Baur said. "All the animals there feel it, and the people feel it, and it's just unhealthy."