One of the primary constraints to animal production is an adequate supply of feed. As the world human population increases, with consequently increased demand for animal products (especially proteins) in the human diet, there must be increases and improvements in the supply of feed for animal production.

Much of the improvement in animal productivity of meat and milk that has taken place in the U.S. during the past 2 or 3 decades has resulted from extensive use of feed grains. Attention should continue to be given to feed grain production because of its importance, with emphasis on the potential for genetic improvement by plant breeders. There is evidence, however, which suggests that the importance of grain as a feed base maybe declining and that its place, especially for ruminant animals, will be taken, to an increasing degree, by forage or alternate feed sources. Other uses of grains, including their export as an international trade item and their domestic use as a fermentation base for liquid fuel production, as well as decreased demand for lean meat, all contribute to this trend.

There is also an increasing emphasis on conservation of resources, which will increase the cost of land and water and the inputs required for feed grain and forage production. Excessive soil loss from mismanaged cropping is coming under increasing criticism and regulation.

Given that animal production systems in the 21st century will be subject to higher energy costs and that instability will result from alternate demands for a limited supply of grain crops, the exact type of enterprise for the future cannot be predicted. Yet the forces impinging on feed production for animals could lead to a new era in which the animal production systems are part of the total resource conservation for nutrients, water, soil and energy, while producing the feed needed.