The 1911 book quotes "corn (grain)" as being "used very extensively" for dairy cows, and lists it separately from "corn and cob meal" and "ground corn, cob, and shuck meal"? This does not sound like the grass.
However, it does say that the "unhusked ear" broken from the stalk is the most popular feed in the West for fattening cattle (those that are eaten) and "Corn Meal" is favored in the East.
The 1886 and 1822 quotes look like they are talking about using the whole plant, not just feeding animals the ears or grain.
Not really related to your comment, but corn is actually a grass (grasses are a taxonomic group within the plants), so it would be technically accurate (albeit misleading) to say that a cow fed nothing but corn is also "grass fed."
You make some good points, and it's probably around the late 1800s that the move to corn grain became more common. I should note also that studies clearly show health benefits of "grass"-fed corn (higher Omega 3s for example).
It's true corn is a grass. Actually, all true grains are grasses, I believe, and farmers are allowed to feed a percentage of grain crops and still call their animals "grass fed" if they feed the young sprouts (pre-seed), but the FDA (or USDA?) doesn't allow them to call it grass-fed otherwise.
I wonder what term could be used to replace "grass-fed" that would more specifically define what is meant.
If I was an evil person working for the marketing department of an evil mega-factory-farm, I would hire you right this instant on the basis of that last comment alone. Evil genius.
However, it does say that the "unhusked ear" broken from the stalk is the most popular feed in the West for fattening cattle (those that are eaten) and "Corn Meal" is favored in the East.