Cattle ranching was problematic for the Plains Indians as cattle and buffalo competed for grass to eat. As the amount of cattle on the Great Plains rose, the amount of buffalo declined because there was not enough space or grass for both to survive. In 1860, Nebraska had just 37,197 cattle. This had risen to 1,113,241 by 1880!  

Sometimes Plains Indians attacked cowboys who were on their land. In response, the US army was ordered to protect cowboys which meant Plains Indians were brought into conflict with the army.