During the summer months the cows are outside on pasture between milkings. Before each milking, someone has to "get" the cows. When we were kids it was our first farm chore, and about the only one I didn't absolutely hate. Someone walks up into the field and herds the cows down to the barn in front of them.
To get the cows we yell "C'mon cows, c'mon." When getting the cows was my job I used to stand along the road and shout at the top of my lungs. Most of the cows came. One time a cow that had just calved didn't come, and wasn't noticed until all the others were in the barn. My dad has a pretty memorable scowl, and very little patience at milking time, after that I walked my sorry self up to the top of the hill to make sure all the cows were accounted for.
Cows are used to a set milking schedule. If the milkers are a few minutes late, the cows will be standing at the fence waiting for them. Our daytime pastures are on one side of the road, the barn is on the other. The cows gather in a loafing area.
When all the animals are assembled, they walk across the road.
From here they go into the barnyard, then into the barn. Our barn has two rows of stalls, each with a door to the barnyard, facing into a center aisle. With a bit of practice, each cow learns which door she enters the barn through and which stall is her assigned space.
I've been trying to catch my father calling the cows for months now. Like the amish, he disappears when the camera comes out. My persistence paid off (or wore him down), you can see the video here.