What demographic change fueled the growth of the cattle industry in the late 19th century?

The growth of the cattle industry in the late 19th century was significantly fueled by increased westward migration. This movement involved a large number of settlers moving into the Great Plains and other areas west of the Mississippi River, seeking new opportunities and land for farming and ranching. As these settlers established homesteads and farms, the demand for beef grew significantly, providing a lucrative market for cattle ranchers.

Moreover, the construction of the transcontinental railroad during this period allowed for the faster transport of cattle to markets in the East. The combination of these factors created a booming cattle industry, as ranchers capitalized on the increased migration and the accompanying demand for meat.

The other choices do not adequately account for the specific demographic shifts that influenced the growth of the cattle industry. A decrease in population would have negatively impacted the demand for cattle, while the expansion of agricultural practices generally focused on crops rather than livestock. Likewise, while foreign trade agreements could have had some impact, the primary driver was the local population growth resulting from westward migration. Thus, the growth of the cattle industry can be closely linked to the increased movement of people into the western territories during this time.