She often advocates euthanasia, or, as she calls it, taking animals “over the rainbow bridge.” The men want to work them to the end.
After she gave Mr. Abu Ghoneim her recommendation, his face darkened.
“It is only God who takes life away,” he said.
For generations, the men of Nazlet el-Samman have made their living by offering horses — and camels — to tourists to ride around the Great Pyramids. Or, like Mr. Abu Ghoneim, they rent their horses to prance, gaily decorated, in raucous street weddings.
The men are paid the equivalent of $7 for an hourlong ride around the Pyramids and $20 for a 20-minute wedding dance. Yet no matter how much the men need the animals, they work them until they collapse from exhaustion. The carcasses are then unceremoniously tossed in nearby dunes.
After the Arab Spring uprising in 2011, tourism to Egypt collapsed, to 3.3 million tourists so far this year from 14.7 million in 2010. Horses starved. Camels were sold for meat.
Alongside a veterinarian from the Brooke Hospital for Animals, which has made free weekly visits for years, a parade of animal rights groups rushed to help. One group fed horses for free until it ran out of money. Ahmed al-Shurbaji, 34, who runs a nearby dog shelter, sometimes comes by with a vet to treat light injuries.
Then there is Ms. Barton, 56, who became a jillaroo, or ranch hand, in Australia at 15.
On a recent visit to Nazlet el-Samman with Ms. Barton, I had a feeling that it had hardly changed since 1931, when Dorothy Brooke, an Englishwoman living in Cairo, wrote a letter to a British newspaper soliciting funds to euthanize aging World War I horses that were sold to Egyptians.
“The majority of them drag out wretched days of toil in the ownership of masters too poor to feed them — too inured to hardship themselves to appreciate, in the faintest degree, the sufferings of animals in their hands,” Ms. Brooke wrote. She later established Brooke, now a global charity.
Horses were everywhere in the slum, tied to trees and their troughs lining alleys like equine parking lots. Plenty were gaunt, their ribs showing through their skin. A foal galloped past me and sniffed at a woman walking by. Men picked up their children on horse-driven carts and carried home groceries.
When word filtered out that there were tourists at the Pyramids, some of the men took their horses and headed off.
On a recent day, Ms. Barton gave colorful pads to Mamdouh Abu Basha to wrap around the chains that stretch across his horses’ noses, creating welts. She complimented their healthy, shiny coats.
Salem Abu Basha asked Ms. Barton whether she could treat his gray mare, which was suffering from a leg infection. The mare was not responding to a poultice of yogurt and starch, a Pharaonic treatment that usually worked, he insisted.
The animal was whisked to Ms. Barton’s clinic. There, a sick horse lay on the ground. Ms. Barton wanted to put it down, but the owners took it back a few days later and put it to work. Donkeys clustered in a paddock near the Abusir pyramids, one of several pyramid groupings that dot the area.
A teenager wanted to know whether Ms. Barton could heal his donkey, whose hoof had fallen off from an infection. She offered to take it for six months, but the youth, Gomaa, declined. He needed the donkey to pull his cart, which he used to recycle plastic for $5 a day.
“I rested him for a month already,” Gomaa said, leading the limping donkey away.
Then two men appeared, leading a mare bearing a sore where a saddle had rubbed away her skin.
“Doctora!” they called.
Ms. Barton’s face hardened when she recognized the mare from the bloody gashes across her sides. She said the wounds were from a stallion’s leg, because she had seen the men forcing the mare to breed in the evenings. Was she being punished?
In broken English, one man explained, “She do bad things, so we should — we should learn her.”
“Learning her what?” Ms. Barton said. “She does bad things, so you get the stallion to jump on her? This is how you teach her not to be bad?”