Branding of livestock was a common practice to indicate ownership. It entailed burning a mark on livestock using a hot iron.
Most cows were branded on the left hip. Rustlers who were good at altering brands after pilfering the cows were known as "brand artists".
In the American West, a branding iron consisted of an iron rod with a seal-like mark which ranchers heated in a fire. After the branding iron turned red-hot, the rancher pressed the seal-like marker against the hide of the cow.
The unique mark meant that the cow could then graze freely among other cattle on the free-range of the American West. Drovers could then separate the cattle at round-up time for driving to market. These customs of the American West evolved from the practices of the vaqueros (a Spanish term for "cowboy")..