Grazing allows animals to roam and directly consume forage: grasses, legumes, and forbs, on rangeland or pasture.
Farmed animals that are ruminants generally spend at least some portion of their lives grazing. A ruminant “characteristically has a stomach divided into four compartments and chews a cud that consists of plant food that is regurgitated when partially digested.”[1]
The vast majority of farmed animals that graze are cattle raised for beef or dairy products, with sheep and goats also grazing.[2]
“ruminant” American Heritage Dictionary, n.d.
USDA (2024) 2022 Census of Agriculture, United States, Vol 1, Part 51, Tables 12, 27 & 28.
Ruminants have evolved to digest and metabolize cellulose which is the essential part of the solid framework of plants – highly fibrous and indigestible to most animals.[1] The grains and oilseeds fed to factory farmed pigs and poultry are not easily digested by ruminants and often create digestive and other health problems, which are then treated prophylactically with antibiotics.[2-4]
The economics of a cheaper food source also plays a role. Over 40% of the continental U.S. is considered grazing land.[5] The topography, soil characteristics, and water availability in these areas usually limit agricultural uses. It has become accepted that cattle, sheep, and goats grazing on these lands “render productive vast portions of otherwise unusable land.”[6] This, of course, presumes that land is not productive if it cannot grow food for humans, even if it does support natural ecosystems, biodiversity, and sequestration of carbon.[7-9]
Lee Rinehart (2008) Ruminant Nutrition for Graziers, USDA NRCS, Publication of National Sustainable Agriculture Information Service, pp. 2 and 4.
Francis Fluharty (2017) How to transition calves to grain-based diets, Farm Progress. https://www.farmprogress.com/livestock/how-to-transition-calves-to-grain-based-diets
USDA (2011) FAD PReP Beef Feedlot Industry Manual, Animal and Plant Health Inspection Service, pp. 9, 16, 17. [Cattle sent to feedlots are slowly transitioned to a diet with corn and soy products, are often given antibiotics prophylactically, and must be kept relatively healthy for an average of 5 to 6 months prior to slaughter.]
Winters-Michaud, C. et al., (2024) Major Uses of Land in the United States, 2017, USDA ERS Bulletin No. 275, Table 1.
PewTrust.org (2021) FDA Must End Unnecessary Long-Term Antibiotic Use on Farms and Feedlots. https://www.pewtrusts.org/en/research-and-analysis/articles/2021/06/01/fda-must-end-unnecessary-long-term-antibiotic-use-on-farms-and-feedlots [Antibiotics are regularly given to cattle on feedyards to prevent liver abscesses, a condition associated with the highly enriched grain-based diets that cattle growers use to rapidly increase animal weight before slaughter.]
Lee Rinehart (2008) p. 3.
Asner, G. P., et al., (2004). Grazing systems, ecosystem responses, and global change. Annu. Rev. Environ. Resour., 29, 261-299.
Hovick, T.J. et al., (2021) Rangeland Biodiversity, Rangeland Wildlife Ecology and Conservation, McNew et al. (eds.) Ch. 8, p. 217. [“Given the large amount of land that is used for livestock production, it is not surprising that livestock herbivory has profound impacts on rangeland biodiversity.”]
USDA Forest Service (2021) Do you Know Where Your Rangeland Carbon Is? https://www.fs.usda.gov/rm/pubs_journals/rmrs/sycu/2021/sycu5_2021_11_rangeland_carbon.pdf
Out of total land in the continental U.S. (1.9 billion acres), grazing land accounted for 803 million acres in 2017, or ~42% of continental U.S. land area.[1]
Livestock grazing was the primary use on ~658 million acres (grassland pasture and range). This is about 35% of total land in the continental U.S.
Winters-Michaud, C. et al., (2024) Major Uses of Land in the United States, 2017, USDA ERS Bulletin No. 275, Table 1, p. 5. [total continental U.S. land area = 1,891 million acres. Total grazing land = 803 million acres. 803 /1891 == 42.5%]
Grassland pasture and range is the predominant type of land that is grazed, accounting for 658 million acres.
Forestland that is grazed totals 132 million acres.
Cropland used only for pasture totals 13 million acres.[1]
Winters-Michaud, C. et al., (2024) Major Uses of Land in the United States, 2017, USDA ERS Bulletin No. 275, Table 1, p. 5. [Total is for the continental U.S.]
Grassland pasture and range, the predominant type of grazing land, is concentrated in the Mountain and Southern Plains regions. In the Mountain region, grazing accounts for ~60% of the region’s total land area; in the Southern Plains, grazing accounts for ~58% of the region’s total land area.[1]
Winters-Michaud, C. et al., (2024) Major Uses of Land in the United States, 2017, USDA ERS Bulletin No. 275, Table 2. [Mountain states: Grazing on 331 million acres – Montana, Idaho, Wyoming, Colorado, New Mexico, Arizona, Utah, Nevada. Southern Plains states: Grazing on 123 million acres – Oklahoma, Texas.]