According to the National Corn Growers Association, about eighty percent of all corn grown in the U.S. is consumed by domestic and overseas livestock, poultry, and fish production. The National Corn Growers Association also reports that each American consumes 25 pounds of corn annually. The crop is fed as ground grain, silage, high-moisture, and high-oil corn. About 12% of the U.S. corn crop ends up in foods that are either consumed directly (e.g. corn chips) or indirectly (e.g. high fructose corn syrup).
Of particular note is Table 30--Indexes of feed-consuming animal units, which provides feed consuming animal units based on species and type of feed. This could be used to show which animals are eating which grain/feeds.
Not sure exactly what I'll do with this, but just want to put this stuff here so I don't lose track of it if I figure something out in the future.
From Ag 101 (EPA):
They give the source as this NCGA publication, which, in turn, uses USDA ERS Feed Outlook as its source.
All USDA ERS data can be queried here: http://www.ers.usda.gov/data-products/feed-grains-database/feed-grains-custom-query.aspx
And downloaded in bulk (excel spreadsheet) here: http://www.ers.usda.gov/data-products/feed-grains-database/feed-grains-yearbook-tables.aspx
Of particular note is Table 30--Indexes of feed-consuming animal units, which provides feed consuming animal units based on species and type of feed. This could be used to show which animals are eating which grain/feeds.