Actually, you're incorrect. He did not just list people only <i>advocating</i> the use of corn. The titles were advocating the use of corn, but if you actually look at some the references you can see that cows were not being grass fed.<p>Quote from the 1911 book that he cites:
"Corn Grain This grain is used very extensively in American dairy rations because it may be successfully grown in sections of the United States. It is relished by cattle. It high in carbohydrates and when supplemented feed to complete the ration the latter must roughage and be nitrogenous in character. When grain is fed some of it passes through the animal for this reason it is well to grind it and feed it as corn meal.<p>For the cattle that are eaten (non-dairy), Snapped Corn is the "most popular feed in the west" and "Corn meal seems to be favored by Eastern feeders"