When I was a youngster, my Dad used to raise cows and steers all the time. I remember one particular steer that my sister and I named Lemon. We knew that Lemon's ultimate destinations were the freezer and the stove, but we treated him as much like a pet as we could.
My Dad kept Lemon in a pasture where he grazed all day on green grass. We would keep his barn filled with hay and straw. During the summer, we fed him the leaves, shucks, and stalks from the corn we picked out of the garden. He also got watermelon rinds and every other bit of veggies from the gardens that we didn't eat. Starting in September, my Dad would take my brothers and I out to large corn fields where we would glean left over corn from stalks that the farmers couldn't reap. We would take the corn back home, shuck it in a hand cranked corn shucker and use it to feed Lemon, the cow and our hogs.
I remember eating a steak from Lemon that my Dad cooked on a wood stove that he used to keep in the basement. It was a T-bone. It was pretty good. I suppose one could say that Lemon was grass fed. But, we never worried about such things.
Here is an interesting article that fellow beef lovers might find interesting.