“Don’t get me started on the Amazon,” Mr. Lima said, referring to the vast river basin where, the authorities say, the expansion of Brazil’s ranching frontier has illegally destroyed large tracts of the rain forest. “I’ve flown over the Amazon in a small plane, and all I saw for hours was trees. Trust me, we can deforest a lot more if we have to.”

Mr. Lima’s readiness to voice publicly what many Brazilians say in private reflects, perhaps, a yearning for the spotlight. As he roams the backlands rodeo circuit in his Mitsubishi Titan pickup, the competitions where Mr. Lima works are often as much about him as they are about bull-riding buckaroos.

At a rodeo here in Goiânia on a recent Friday night, scantily clad female dancers warmed up the arena before Mr. Lima burst onto the scene around midnight, his arrival heralded by fireworks, a nightclub smoke machine, cannons discharging confetti into the air and a dance involving a good deal of strutting by Mr. Lima himself.

After singing Brazil’s national anthem, he led competitors in a lengthy prayer before getting on with the event. He often cracks jokes, exudes pride in Brazil’s ranching culture and bursts into song while describing the technical aspects of the cowpokes competing for prize money.

“I love the United States and recognize how much we owe to the rodeo scene up there, but the folks in Brazil expect a little more from their rodeo announcers,” he explained. “What am I, essentially? A storyteller.”

Mr. Lima got into radio announcing after studying three things: law, journalism and how to be a clown. He said it was during his time at clown school in Rio, when he was trying to find a way into show business, “that I learned the valuable lesson of laughing at my own failures.”