Answer:
Rail communication between Texas and the rest of the United States was insufficient during most of the 18th century. Texan ranchers needed to take their livestock to a place where it could be distributed and sold to the rest of the country.
The best place was Saint Louis, Missouri, because the city became the port of entry to the American West, and connected the West with the East with rail lines.
Texan ranchers therefore hired cowboys to transport the cattle from Texas to Missouri in a long, dangerous journey. The cattle could get stolen in the way, or it could become stray. Thus, the job of the cowboy was a very difficult and important one.
