Alison London/Corbis

“Dear Father,” the announcer intoned over the darkened arena, “we ask that you put your mighty hands on this event, not only on the cowboys, but on the livestock as well.”

The 7,500 fans crowding the Rose Garden in Portland, Oregon, to see the rodeo—an event put on by Professional Bull Riders, Inc., and one steeped in God and country—went hush. Earlier, a lieutenant colonel from the U.S. Air Force had marched, ramrod-erect, onto the loose dirt of the bullring and asked 23 saluting recruits to solemnly raise their right hands, so as to be sworn into the force. A battery of explosives burst in the darkness, leaving three fiery letters—USA—burning bright in the soil. Then, as dry-ice fog crawled the arena, a spotlight settled on a man in a white cowboy hat, his hands on his hips Old West–style, his cold grimace terrifying, as the announcer hailed “the reigning … world … champion!”

Guilherme Marchi? From Leme, São Paulo, Brazil?

Well, yes. Brazil has the world’s largest commercial cattle herd—more than 200 million head—and its own burgeoning rodeo culture. And now, as the PBR launches its 17th season, bringing its 40-rider show to 31 cities coast to coast, several Brazilian riders are in the hunt for the tour’s $11 million in prize money—and for the Ford 4x4 pickup bestowed upon the winner of the PBR World Finals, slated for November, in Las Vegas.

The riders mount snorting 1,800-pound animals specially bred to kick and buck. They endeavor to stay on for a full eight seconds, and last year Marchi, who’s 27, succeeded about 60 percent of the time. He is square-jawed, with plaintive brown eyes and a little crease of a scar in his chin, thanks to a cow that kicked him when he was 6. When he appeared recently on the cover of PBR’s media guide, shilling for what promoters call “the toughest sport on Earth,” the scar was displayed prominently, and Marchi was festooned with every imaginable emblem of cowboy masculinity: ropes, a fist-sized belt buckle, leather chaps.

Away from the spotlight, though, the machismo vanishes and Marchi exudes a common touch, climbing over 10-foot fences to be photographed with fans. “He talks American pretty good,” Dean Woods, a retired heavy-equipment operator, told me. “And he’s not like your basketball and football players—he stops and signs autographs.”

Marchi had plenty of Portuguese-speaking company in Portland. Wiry Renato Nunes performed a backflip off the bullpen fence. Paulo Crimber, from São Paulo, often moonwalks in the ring. Robson Palermo—5 foot 6, 163 pounds, and a bit chubby for a bull rider—has tried dirt dancing, too, but he stuck to bull riding when I saw him. “I have three slipped discs,” Palermo, the 2008 Vegas winner, told me backstage, afterward, “and I’m not a very good dancer.”

A moment later, Palermo was genially grinning as my interpreter showed him cell-phone photos of her children. “It’s funny,” he confided. “Sometimes when you’re with the bulls, you’re laughing and joking. And then you see the TV cameras are on you, so you have to act all serious and mean.”

The pose doesn’t come naturally to the Brazilians, for in their country rodeo is more homey than steely. The 10-day Barretos International Rodeo, which draws 800,000 fans every year, is a sort of festive state fair, replete with petting zoos, outdoor concerts, and barbecue joints. The prize money is paltry, and the cowboys bear a sense of inferiority. “Rodeo is just getting popular in Brazil,” Marchi explains, “and so you want the fans to like you. You try to be nice.”

Palermo once made $30 a month as a cattle hand, and lived with his parents in a remote shack with an outhouse. There was no TV reception, but if he cranked the generator, Palermo could watch bull-riding videos. He learned the art, at first, by bucking and heaving about on his tattered couch.

Today, he’s earned more than $1 million on the PBR circuit. With his wife and infant daughter, he lives on his own Texas ranch, an 82-acre spread in Tyler. He has 10 horses, and he is breeding bucking bulls. But what he cherishes most is the mounted deer head that an admiring PBR fan gave him for his wall. “In Brazil,” he mused, “we only kill deer to eat them. It’s strange what people do in this country, but I think I’m staying. I like it here.”