“It’s a tough, rapidly changing business,” said Marshall Ernst, a cattle rancher from Windsor, Colo., who serves as senior director of livestock operations at the two-week stock show, which runs through Sunday. “Those who are not taking advantage of new technology or are resistant to change may not be able to survive.”

Finding good, knowledgeable cowboys has also become harder, as more people have moved to cities away from the rural communities that raised them, cattlemen here said. And these days, ranchers must spend considerably more money and time on marketing their cattle over the Internet to stay relevant and profitable.

At a showcase of breeding cattle last week, ranchers drawled quietly into their cellphones, negotiating sales and checking on business back home. From his front-row seat, Newley Hutchison, a sixth-generation rancher from Seiling, Okla., whose ancestors were original homesteaders, watched intently as a set of prized heifers he was trying to sell stared blankly out at the crowd. He talked of the mounting pressure ranchers feel to keep up with all the advancements, like the newest genetic markers being used for herds and the latest computerized equipment to maximize the efficiency of land.

Still, Mr. Hutchison said, some aspects of ranch work will never change.