Back in the day, leather cuffs which covered the forearm and wrists were worn by cowboys to prevent injury while tending cattle and during branding. Along with gloves the cuffs provided a line of defense against brush, cactus, hot branding irons and dangerous rope burns and cuts.
Leather Cowboy Cuffs
Did you ever take a rope in your hands when your catch was trying to run away from you? Just let it slip a little and you will know what happens. Well that's what the cuffs are for. If the whirling lasso were to run over the roper's arm it would cut it to the bone. So he wears gloves on his hands and cuffs on his wrists. (Excerpt from 1924 article in the Nor-West Farmer titled THE TRUTH ABOUT THE COWBOY as told by Kootenay Brown an American, born in the Territory of Idaho.)