While the diet provided to finishing cattle in feedlots relies on some humanedible inputs (i.e., corn grain), the forages and by-products fed to cattle throughout their lives are largely inedible to humans.2
For example, once the entire lifetime feed intake of cattle is accounted for (meaning all the feed they consume from birth to harvest), corn only accounts for approximately 7% of the animal’s diet.3
The other 93% of the animal’s lifetime diet will consist largely of feed that is inedible to humans, and thus not in direct competition with the human food supply. Unlike humans, cattle can efficiently digest fiber and convert human-inedible feeds into nutritious, humanedible foods.
One of the major human-inedible by-products fed to beef cattle is distiller’s grains, which is a by-product of alcohol production from corn (either for fuel or human consumption). The amount of distiller’s grains fed to beef cattle has increased in recent years as the production of fuel from corn has increased. As Table 1 demonstrates, the proportion of corn used for fuel production in the United States relative to animal feed has dramatically increased in recent years. In contrast, the percentage of corn used for human food has been relatively unchanged.
Using recent data as a guide, one can predict that land used to grow corn for animal feed would likely be shifted to grow corn for fuel use if less corn grain were fed to beef cattle, and would not shift towards human consumption. Altering the lifetime consumption of corn grain by cattle, which is only approximately 7% of an average animal’s total lifetime feed intake,3 would likely have a very minor impact on the sustainability of land use.
Corn production, like all crop production, does have an environmental sustainability impact. Thus, reducing corn’s environmental impact through better production practices and using new technologies would improve land use sustainability regardless of the corn’s end use (human food, animal feed, or fuel). Such improvements include no-till or conservation tillage practices to reduce soil erosion and increase soil organic carbon,5 winter cover crops to reduce nutrient run-off,6 and precision agriculture techniques to apply fertilizer at variable rates across a field to minimize nutrient emissions to the environment while improving corn yields. Indeed, past improvements in crop yields, including corn, have contributed to reducing environmental impacts per unit of beef 12% from 1970 to 2011.7