Livestock producers have struggled with rising grain prices for years now and with feed accounting for 60 - 70% of the costs for animal production, investing in alternatives has become a necessity.
Demand for renewable fuel has put stress on corn supplies. The animal agriculture industry has seen feed costs rise dramatically as mandated ethanol production has ramped up. The politics of ethanol production may change as food prices rise, but for now livestock producers cannot rely entirely on corn.
As the population increases, more farm land is developed for houses, factories, roads, etc. At some point we will not be able to plant enough grain to meet the growing demand.
Cellulose could become a very significant source of animal feed. Cattle and other grazing animals break down cellulose with the help of microbial enzymes in the rumen. Cellulose can also be turned into feed for non-ruminant animals like poultry and swine with the help of enzymes. This natural process is called solid state fermentation and it employs fungi to break cellulose down into smaller, digestible molecules.