 After trucks became popular in the 1910s , the Omaha Stockyards grew exponentially . Cattle , hogs and sheep were shipped cheaper by truck than by trains . In 1919 27 % of livestock at the Stockyards was shipped by truck ; by 1940 's it rose to over 75 % . In 1955 the Stockyards became the biggest livestock distribution center in the United States , and almost all of the cattle was shipped by truck . 
 After trucks became popular in the 1910s , the Omaha Stockyards grew exponentially . Cattle , hogs and sheep <a href='uninflect' title='1'><mark>were</mark></a> shipped cheaper by truck than by trains . In 1919 27 % of livestock at the Stockyards was shipped by truck ; by 1940 <a href='null_genetive' title='2'><mark>'s</mark></a>it rose to over 75 % . In 1955 the Stockyards became the biggest livestock distribution center in the United States , and almost all of the cattle was shipped by truck . 
After trucks became popular in the 1910s , the Omaha Stockyards grew exponentially . Cattle , hogs and sheep was shipped cheaper by truck than by trains . In 1919 27 % of livestock at the Stockyards was shipped by truck ; by 1940  it rose to over 75 % . In 1955 the Stockyards became da biggest livestock distribution center in the United States , and almost all of tdacattle was shipped by truck .