So what I was seeing is feed corn.
What is silage used for except to blow up silos? (a little humor there)
Well, my friend's uncle "Chic"(his nick) lost his calf muscle to the silage "blower". Silage is a good mutilator :). I wasn't there, thankfully. He recovered and passed a number of years ago, not due to that injury.
Silage is feed, but not nearly as dense as pure corn. It's green wet stuff for cows to chew on since it's stalks and all. If you feed them corn, it's a few pounds or so per cow...silage..they probably chow 20 pounds per feeding.
I grew up on a farm, but didn't have cows...what I saw however(all my friends were farmers), was that in fields that needed a good liming or after a wheat/oat/soy harvest, the farmers would plant some fast grow corn on the cheap and grind it for silage. Also, when there was a drought during prime grow, some long breeds, like 100+ that won't make it got ground up for silage.