20 November 2001

The Emerald Steak: How do beef cattle and grazing affect the environment

Humans cannot consume most cattle feeds, and animal proteins are more biologically available to humans than many plant proteins.1

Cellulose, the most abundant structural substance in plants, remains indigestible to humans, but the rumen—the first of a beef animal's four stomachs—enables it to consume large quantities of cellulose and digest 30 to 80 percent, turning it into nutritious meat or milk.2 Thus, cattle add value to the otherwise unusable forage resources found on two-thirds of 1.2 billion acres of agricultural land in the United States, 734 million acres of which consists of rangeland or forest pasture.3

Most forms of livestock production have become more geographically concentrated over the last several decades (eg. the growing size of a smaller number of feedlot businesses or the increased size and geographical concentration of chicken production in certain parts of the country). A mother cow’s ability to utilize forages on large, otherwise unproductive areas takes away the common “economy of scale” incentives for increased concentration of livestock farms.4

Several environmental benefits to well-managed grazing have become evident. The waste disposal problems inherent to concentrated operations poses a pollution risk, and decentralized production and processing could also help protect the food supply from a bioterrorist threat by presenting a more diffuse target.5,6

On several occasions including the 1994 fire season in Chelan County, Washington, grazing reduced the buildup of the underbrush that carries and intensifies wildfires on range and forest lands.7 The root permeation and the nearly year-round root activity of grassland soils also allows them to function as an excellent biological filter for surface water. A USDA-Agricultural Research Service study showed groundwater samples from a grassland watershed to be as good as or better than those from a nearby forested area.8 This ability allows these areas to aid in waste management by capturing and assimilating strategically applied organic waste.

And well-managed grazing animals can actually enhance wildlife habitat. Grazing lands enhance cover and feed habitat for birds and small mammals when residual cover is maintained. Minnesota and Wisconsin studies observed fish populations two to three times larger in streams having intensively managed grazing on their banks versus streams where no grazing occurred.9 Given people’s growing willingness to pay for fishing or hunting leases, the wildlife conservation in connection with grazing lands might begin to have some private incentive.10

Extended periods without grazing hamper a plant’s ability to grow vigorously. Grasslands then lose some of their effectiveness in capturing carbon dioxide through photosynthesis, holding the soil with a vigorous root system, and building soil fertility through the cycle of growth and decay. Farmland planted to grass and left idle increased the soil carbon content by ½ ton on average over the first five years.11 These results might have increased with intensively managed grazing (grazing animals on smaller pastures for shorter periods of time, avoiding overgrazing by preserving sufficient residual grass height, and allowing long rest periods for pastures to regrow before the animals come back).12

1J. W. Oltjen and J. L. Beckett, “Role of Ruminant Livestock in Sustainable Agricultural Systems,” Journal of Animal Science, Vol. 74, No. 6, June 1996: 1406-1409.
2National Cattlemen’s Beef Association, Cattle and Beef Handbook, (National Cattlemen’s Beef Association, Englewood, CO, Sixth printing June 1999) p. C-4.
3USDA, “1992 Natural Resources Inventory,” July 1994, in NCBA, Cattle and Beef, C-3.
4USDA, Economic Research Service, Change in U. S. Livestock Production 1969-1992: 22.
5Larry Swisher, “Veneman: More protection needed for ag production, food supply,” Capital Press, E. OR/E. WA Ed., No. 43, Friday, 26 October 2001, p. 25.
6“Editorials—There may be safety in numbers,” Capital Press, E. OR/E. WA Ed., No. 41, Friday, 12 October 2001, p. 6.
7Bill Laycock, Department Head, University of Wyoming Range Science Department, July 1994, in NCBA, Cattle and Beef, C-4.
8GLCI News, January-February 1999. www.glci.org/JanFeb99.htm.
9GLCI News.
10National Cattlemen’s Beef Association, “The Ranching Economy,” www.beef.org/library/environment/economy.htm
11USDA National Resources Conservation Service, Non-Federal Grazing Lands in the United States, 1996.
12S. J. Reeder and G. E. Schuman, “Effects of Grazing on Carbon Sequestration,” USDA-Ag Research Service, Crop Research Lab. Ft. Collins, CO, under “Amazing Graze.” on www.eatwild.com

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