What was the original task of the buffalo soldiers?

Horses were considered valuable military assets in the 1800s. Too valuable to be entrusted to "colored" troops. So they has the Black troops march from place to place. (The officers were white and got to ride horses.) They were used out west to help subdue the Indians. The Indians were the ones who called them buffalo soldiers. First because of their hair, which reminded the Indians of the wool of the bison and also because they were tough troops and hard to stop, as the Indians found out fight after fight.