As the oats begin to turn to its yellow color, combines will enter fields to harvest the crop although in some fields, a different type of horse power will be used to pull a grain binder instead. The small bundles are often made into stacks in the field to dry before the threshing begins.
Horses Pulling Grain Binder
Watch the oats being harvested with a horse-drawn grain binder.
https://youtu.be/HLyZLlJY_ME&w=640&h=430&rel=0