Answer:
Western Expansion
Step-by-step explanation:
During this era, major expansion into the west occurred, allowing for many new cattle ranches to be developed.
However, before the late 19th century, rail stations to transfer these cattle to areas which they could be sold for high prices (usually cities in the east) were scarce or far.
Therefore, ranchers hired professionals to pool and transfer their cattle to the rail stations. These professionals often also herded feral cattle.
The process in which this happened are often known as cattle drives.
By the end of Western Expansion era, however, alternate transportation systems became large and robust enough to make cattle driving an obsolete practice.