The purpose of the combine (thrasher in the older days) was to separate the grain from the rest of the plant. The straw, in the case of oats, was saved for bedding to keep the cows warm and dry in the winter. The wheat was excellent food for the cattle and very important in the production of milk.
The combine had a large bin to hold the oats until it was time to unload. It would be dumped via a built in auger into a wagon or later into a gravity box on wheels.
Once delivered to the barn by tractor, the oats was loaded into the barn with a long electric powered auger. With the assembly wired up inside the oats bin, the receiving end of the auger sitting in a tub of sorts the ground outside the barn. At first, the oats had to be hand shoveled into the tub as the auger carried it up and dumped it in the bin. Later, Dan bought a gravity box wagon, so the oats would slide out via gravity into the auger tub negating the need to shovel the grain. Great technology, gravity fed wagons!
We had a big wooden (and heavy) boards in the shape of a “T” that we would use to level the oats in the bin as it filled up, pulling and pushing the massive piece of timber. Not a light job. As the bin filled, we would stack up boards in place to keep the oats contained in the bin. Missing knotholes always a problem causing leaks in the retaining wall. My strongest memory of the oats harvest was the choking dust in the oats bin. I recall it taking a long time to end the coughing after a busy day. We didn’t believe in masks. A full bin of fine grain would last the cows all winter until they could be pastured in the spring.
We didn’t feed the cows straight oats. We would mix it with corn and grind up the mixture with a belt driven hammermill that was moved near the double doors of the upstairs in the barn. The belt slipped over the drive wheel, as the tractor was parked outside the barn. The hammermill was a simple, powerful and loud device that sounded like it was possessed by the devil, and about to fly apart. It ground up and pulverized corn cobs into gritty feed for the cattle. There were exchangeable screens inside to change the size of the ground up feed. With a large feed slide, corn would be taken from then corn crib and dumped on the barn floor just outside the oats bin. Several shovels of oats would be shoveled unto the pile of corn, like icing on a cake made of corn cobs. Wayne, Dan or Leo would often shovel the corn / oats mixture into the hammermill. The power of the mill would propel the feed into an overhead storage hold, where feedbags could be connected, a level flipped and the feed fill the bag. We would often have dozen of feed bags all stacked up in the corner to be used to feed the cows. A small trap door by the oats bin was used to dump the feed bags into a feed tank below. From the tank, it feed would be distributed to the cattle by shovel or in my case, a tub. Later, we would throw the corn in the back of the truck, along with the oats, and drive down to the Eureka Co-operative Feed Mill, they they would grind it up in far less time, and bag it (you supplied your own burlap bags). They also would through in a little molasses, and perhaps a little salt into the feed to satisfy the cows appetite. With the truck loaded up, we would head home the 2-3 miles and unload the feed next to the oats bin.
UPDATE:
The oats bin in the northwest corner of the barn still stands empty, with some of the roof boards starting to collapse. The electric grain auger that delivered oats into for barn for years still stands in the back of the shed, tied up under the rafters.