DENVER — Time has changed much in the American West. On some ranches, cowboys round up cattle on four-wheelers and track livestock with drones. While technology is easing tasks, though, some think it is also threatening the skills that make a cowboy a cowboy: roping, riding and a near-religious devotion to hard work.

But for centuries, neighbors have gathered each spring for a day of branding newborn animals. Well-trained cattlemen pull a hot iron from the fire, and calves mewl as curved steel singes hair and burns flesh. Afterward, there is cheap beer and a meal, maybe a band and a dance.

The branding process has been criticized as cruel. And some families have moved to other methods, including freeze brands created with liquid nitrogen and ear tags they can read with an electronic wand. Perhaps the most notable innovation is the calf table, a viselike device that allows people to trap, flip and mark an animal, eliminating the need for a crew of helpers.