SHUNYI, Beijing  One is named Obama, another goes by Son of Bush. They charge tens of thousands of dollars for sex. Convoys of luxury cars, driven by fans, greet the most expensive studs at airports. Meet the canine gigolos — the purebred Tibetan Mastiffs that have become the latest symbol of China 's growing wealth.

Pet ownership is booming in a nation where dogs and cats are featured as part of meals and animal abuse remains widespread. But none carries the cachet of the Tibetan Mastiff, one of the largest dog breeds, which can weigh 180 pounds.

Last month, a Nanjing breeder paid $234,000 for his purebred pooch, reported the Yangtze Evening Times. In September, a young woman in Xian paid $600,000 for her pet, according to the Xian Evening News. Both led airport welcomes with long convoys of pricey automobiles.

"It's like gambling, as people think they can earn large sums from expensive dogs, but the reality is that it's very hard to breed a top quality purebred Tibetan Mastiff," Beijing breeder Zhao Yanjun says.

Others buy to show off their status. "Like men around the world, Chinese like to own big dogs as it shows 'I am successful, I want to dominate more women and big dogs,' " Zhao says.

In the USA, $5,000 is the upper limit for a show quality puppy, says Martha Feltenstein, president of the American Tibetan Mastiff Association. In China, prices have leapt this year amid a nationwide "Tibetan Mastiff fever" that shows little sign of cooling.

From the frozen steppes and remote monasteries of Tibet to the gated communities of China's urban rich, this guardian dog has come a long way. Movie stardom beckons, too, in two feature-length animations. Tibetan Mastiff, a Sino-Japanese adaptation of a popular novel, premieres next year. In 2011, Tibetan Rock God, based on rock star Zheng Jun's comic book, will follow the hero, Metal, from a Tibetan temple to the Chinese capital.

The dog has changed breeder Zhao's fortunes.

The former chicken farmer, 48, bought his first Tibetan Mastiff in 1990 and earns up to $440,000 a year at his Oriental Treasure breeding center near Beijing.

"They are beautiful, loyal, fierce and run like a lion," he says of the breed, which has a bear-like head and shaggy mane.

Despite enticing offers, Zhao promises never to sell Son of Bush, out of loyalty to his favorite, Bush, who died last year at 11.

"I will never be a high official, but I had fun shouting 'Bush, over here!' " jokes Zhao, who also named and raised Putin, Sharon and several others named for world leaders.

Obama, worth almost $300,000, was born to a dog Zhao sold to Chinese actor Wang Fei. Zhao says Wang charges up to $30,000 per breeding session with Obama.

The top dog among breeders is a celebrity himself. With his "Ma Family Army" of record-breaking female runners, track coach Ma Junren conquered the athletics world in the 1990s. As he pushed his charges through midnight marathons on the high-altitude Tibetan plateau, Ma discovered the region's native Mastiffs.

Ma is still trying to represent his country by pushing for China's full membership in the Fédération Cynologique Internationale (FCI), the World Canine Organization. It's a tough sell, Ma admits, as the FCI is concerned by China's low level of vaccinations, the culling of dogs to prevent rabies and the eating of dog meat.

Those worries are well-justified, says Jeff He, China communication manager for the International Fund for Animal Welfare (IFAW), an advocacy group. Culling continues in some areas, he says, even though vaccination and education are more effective. "The No. 1 threat to companion animals is the lack of animal welfare legislation in this country," he says.

Respect for animal rights is growing, says Qin Xiaona, chairwoman of Beijing's Capital Animal Welfare Association, but the absence of laws slows progress, she says. Last month, Qin rushed to nearby Tianjin to help rescue 800 mostly stolen cats that were locked in cages en route to diners in south China's Guangzhou.

Qin opposes the "Tibetan Mastiff fever."

"They are wild animals, it's cruel to let them leave their habitat," she says. "We should send all of them back to their habitat."

In New York, mastiff owner Feltenstein complains that Chinese traders are importing the large breed into the USA for new owners who simply find them "too much dog," leading to a "huge rescue problem," she says.

"It's unfortunate that the Han Chinese are profiting from these dogs and exploiting them, and breeding in other breeds to make them more ferocious," Feltenstein says.

At American Tibetan Mastiff Association shows, winners parade before a large snow lion flag, a symbol of the Tibetan independence movement that is banned in China.

In response to reports that the purebred Tibetan Mastiff was under threat in its homeland, the China National Kennel Club (CNKC) has sent dozens back to Qinghai province since 2005 and encouraged local authorities to stop their annual cull, says Zhang Xiaofeng, CNKC representative in Beijing. Market forces are helping increase and improve the Mastiff population, he says.

Owner and breeder Zhang Liyan rejects any argument against domesticating the breed.

"Unlike other dogs, the Tibetan Mastiff can be like your son, not just a friend," she says at her Big Sister Zhang breeding center near Beijing. "I can't sell my bigger dogs as they become part of the family," says Zhang, 50, a former restaurant owner who travels to the Tibetan plateau each year.

"When I was young, no one could afford to raise pets, or have a big enough house. But now society has developed, and people are richer."