Animal ag a socioeconomic boon

New study refutes perception that livestock production wastes critical resources that might otherwise be used to produce food crops.

IS a cow eating your lunch? That was the central question examined by a panel of university researchers in a recent white paper from the Council for Agricultural Science & Technology (CAST) as they examined the trade-offs between animal feed and human food production.

Contrary to an oft-repeated misconception, the researchers found that livestock production plays a significant role in the economic and social sustainability of both developed and developing countries and that livestock production is much more environmentally sustainable than the industry's critics might contend.

The peer-reviewed CAST paper uses a science-based approach to examine the "feed versus food" issue and finds that in terms of both land and input usage, livestock production actually utilizes resources that would not otherwise be suitable for food production. Furthermore, otherwise unsuitable land and recycled feed inputs are efficiently converted by food animals into a nutrient-dense food product desired by much of the consuming public.

Among its most important findings, the paper notes that large areas of the planet's landmass are incapable of supporting the production of human food crops. Terrain, soil type and climate render the majority of land currently used for livestock grazing unsuitable for production of vegetable-based foods, but ruminant animals efficiently convert forages into meat and milk products.

The U.N. Food & Agriculture Organization (FAO) estimates that grasslands cover 26% of the world's land area and 70% of the world's agricultural area.

"To feed the 9-plus billion people projected to inhabit the earth by 2050, some are proposing that this land would be best used through systems producing food consumed directly by humans," the paper's authors explained. "There are only two approaches by which this could be accomplished: The first is to harvest the forages currently produced and to feed them directly to humans. The second is to cultivate the grazing land to produce other crops that could be consumed directly by humans."

Both of those options, as it turns out, are impractical on a large scale and pose significant ecological risks in their own right. Because ruminants grazing those grasslands can convert cellulose and non-protein nitrogen and humans cannot, grazing is the best use of the forages that are readily available on the planet's vast grasslands.

Furthermore, the majority of these grasslands are located in areas where, for a variety of reasons, it is impractical to cultivate the land. Based on FAO information, the study looked at areas most suitable for cereal grain production and found that the grasslands outside these highly productive arable regions are generally too dry, wet, steep or infertile to raise cereals continuously without special management (Figure).

"The additional work required to raise cereals includes irrigation, summer fallowing, terracing, drainage, leaching of salts and soil amendments," the authors explained. "To convert these lands to cultivation would destroy the ecosystem, eliminate a major feed resource for grazing ungulates (including livestock), ruin the habitat for wildlife and other species, increase the risk of soil and wind erosion, increase nutrient runoff and decrease soil carbon storage"

In other words, the environmental risks are much too severe to convert a significant amount of grassland into cultivated cereals. In the U.S., for example, the U.S. Department of Agriculture reported in a 2007 study that just 9% of the nation's pastureland was suitable for crop production.

Because the global livestock industry faces considerable challenges as the population grows, the authors concluded that future demands for additional food must be aligned with concerns about the environment, economy and sustainability.

However, they also noted that many consumers, unacquainted with current livestock production practices and business models, do not realize the productivity gains made by modern practices, byproduct feeds and technology.

Specifically looking at livestock feed rations, the authors pointed out that producers generally take advantage of a significant portfolio of byproducts that are not consumed or otherwise utilized by humans — feed ingredients such as distillers grains, cottonseed meal, feather meal and almond hulls (Table).

In one example, the experts estimated that more than half of the industrial waste in the Netherlands originates from the food processing industry. Because livestock can often convert these residues into meat, milk and wool, 70% of the feedstuffs used in the Dutch livestock feed industry originate from the food processing industry; the human-inedible residues generated from the consumption of vegetable oil, sugar and potato products in the Netherlands would produce 87 g of pork per capita per day when fed to pigs.

"All foods have an environmental cost, and that cost is not restricted to foods of animal origin," the CAST report concludes. "At the same time, the benefits accrued to society by the livestock industry are substantial in terms of economic profitability, the supply of high-quality proteins in conjunction with macro- and micronutrients and the provision of cultural and societal standing within developing regions."

Efforts such as the "Meatless Mondays" program to significantly reduce meat consumption in the developed world likely decrease greenhouse gas emissions by not even one-third of 1% — a reduction that would have only a very small environmental impact within the U.S. However, a large-scale reduction in meat consumption globally would have significant deleterious effects on the planet, as well as its inhabitants.

Animal ag a socioeconomic boon

Examples of feeds commonly used within U.S. livestock production systems

Feed source


Human edible?

Forage crops

Pasture grasses, alfalfa, clovers, hays, silages (grass or crop based)



Corn, wheat, barley, millet, sorghum, triticale, oats


Plant proteins

Soybean (meal and hulls), cottonseed (whole and meal), safflower meal, canola meal, peanut meal


Grain byproducts

Distillers grains (wet and dry), corn gluten, wheat bran, straw, crop residues


Vegetable byproducts

Apple pomace, citrus pulp, almond hulls, pea silages



Waste fruit/vegetables


Food industry byproducts

Bakery waste, cannery waste, restaurant waste, candy, potato chips


Sugar industry byproducts

Molasses (cane, beet and citrus), beet pulp


Animal byproducts

Meat and bone meal, tallow, feather meal, blood meal, poultry litter


Dairy byproducts

Milk, whey products, casein


Marine byproducts

Fish and seafood meal and oils, algae



Vitamins, minerals, probiotics, antibiotics, yeasts, flavors, enzymes, preservatives


Source: Council for Agricultural Science & Technology (adapted from Mowrey and Spain, 1999; Sapkota et al., 2007, and Wilkinson, 2011).


Volume:85 Issue:41

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