Yes. The feed is produced as a byproduct of the corn to ethanol process. So is carbon dioxide, which they capture and put into soda pop (as well as other uses). There is a U.S. Carbonic (I think that is the name) plant right next door to the ethanol plant here is South Bend, In.
A couple things to think about...
If we are going to grow the corn for feed or fuel we cannot consider the energy needed to grow the corn because that is going to be the same either way.
If we feed the corn directly to the cattle, there is little BTU energy lost.
If we send it to an ethanol plant we lose BTUs while creating the ethanol and the feed and the industrial gases. There would be little energy lost if we just fed the cattle the raw corn. (I ain't a farmer, so can you feed cattle raw corn? I just don't know).
On the petroleum side, if we burned natural gas in our cars, there would be little BTU cost in making it usable in the cars, whereas there are costs and substantial BTU losses making oil into gasoline or diesel fuel.
Every time we convert something into another form we lose a ton of BTU energy in the conversion process.
Every time we eliminate a step of converting something, we save a ton of BTU energy. We should be looking at ways to burn things in their raw state instead of converting them for current technology.
Personally, I think we should be investing in nuclear plants and make all homes heat with electricity. If cars like the Chevy Volt pan out, we can drive around town on an electric charge and drive longer distances on natural gas. We could all eat grain fed beef and sell the U.S. oil to China!