“Corn grain is a seed first, then a feed,” to paraphrase Pat Hoffman, professor at University of Wisconsin (UW). The starch in corn seed contains energy the seed uses to sprout and grow.
The energy (starch) is protected for overwintering by a coating of zein (prolamin) protein. The zein is resistant to digestion by rumen bacteria, which must break through and degrade the protein coating to access the starch.”