Now, the Hong Kong government agency in charge of managing wildlife is working to preserve the cattle, monitoring their health, tagging them, tracking some with GPS collars, and performing selective sterilizations to keep their numbers in check. Since the agency, the Agriculture, Fisheries and Conservation Department, set up its cattle management team in 2011, more than 300 animals have been sterilized, it said in an emailed response to questions.

Volunteer groups like Ms. Ho’s, as well as similar organizations in other parts of Hong Kong, work closely with the government and the public to protect the animals and handle complaints.

The beasts’ higher profile has given rise to a new breed of residents: urban cowgirls.

Karina O’Carroll, 32, is one of them. As a founder of Sai Kung Buffalo Watch, she takes calls from the public at all hours, responding to reports of cattle blocking roads, and protests from people annoyed by piles of steaming cow patties. All in an effort to maintain bovine-human harmony.

“We have gone to pick up poo to appease people,” she said, explaining to them that “it’s the best thing for your gardens and your plants.”

Ms. O’Carroll does not have a lasso. She has found that the best way to shoo cattle off the road is to jingle some car keys — they will move away from the sound. Failing that, splash them with water. And though she does not carry a six-shooter, she does on occasion fire antimaggot medication at their hindquarters.