Which development hurt the profitability of the cattle business?

The development that probably hurt it is the reduction of open range herding. In history, people could just let their cattle roam freely and find food since the plains were huge and nobody lived in them. Nowadays, this can be problematic because there are more and more people and settlements and roads with cars so free range herding has been drastically reduced which cost the herders a lot.

The re-election of the president abraham lincoln.