In animal husbandry, a concentrated animal feeding operation (CAFO), as defined by the United States Department of Agriculture (USDA), is an intensive animal feeding operation (AFO) in which over 1,000 animal units are confined for over 45 days a year. An animal unit is the equivalent of 1,000 pounds of "live" animal weight. A thousand animal units equates to 700 dairy cows, 1,000 meat cows, 2,500 pigs weighing more than , 10,000 pigs weighing under 55 pounds, 10,000 sheep, 55,000 turkeys, 125,000 chickens, or 82,000 egg laying hens or pullets.
CAFOs are governed by regulations that restrict how much waste can be distributed and the quality of the waste materials. As of 2012 there were around 212,000 AFOs in the United States, 19,496 of which were CAFOs.
Livestock production has become increasingly dominated by CAFOs in the United States and other parts of the world. Most poultry was raised in CAFOs starting in the 1950s, and most cattle and pigs by the 1970s and 1980s. By the mid-2000s CAFOs dominated livestock and poultry production in the United States, and the scope of their market share is steadily increasing. In 1966, it took 1 million farms to house 57 million pigs; by 2001, it took only 80,000 farms to house the same number.MacDonald, James and McBride, William (January 2009). "The transformation of U.S. livestock agriculture: Scale, efficiency, and risks", Economic Information Bulletin, No. EIB-43, United States Department of Agriculture.
Definition There are roughly 212,000 AFOs in the United States, of which 19,496 met the more narrow criteria for CAFOs in 2016. The Environmental Protection Agency (EPA) has delineated three categories of CAFOs, ordered in terms of capacity: large, medium and small. The relevant animal unit for each category varies depending on species and capacity. For instance, large CAFOs house 1,000 or more cattle, medium CAFOs can have 300–999 cattle, and small CAFOs harbor no more than 300 cattle.
The table below provides some examples of the size thresholds for CAFOs:
Animal Sector Large CAFOs Medium CAFOs Small CAFOs Cattle or cow/calf pairs 1,000 or more 300–999 Less than 300 Mature dairy cattle 700 or more 200–699 Less than 200 Swine (weighing over 55 lb) 2,500 or more 750–2,499 Less than 750 Turkeys 55,000 or more 16,500–54,999 Less than 16,500 Laying hens or broilers (liquid manure handling systems) 30,000 or more 9,000–29,999 Less than 9,000 Chickens other than laying hens (other than a liquid manure handling systems) 125,000 or more 37,500–124,999 Less than 37,500 Laying hens (other than a liquid manure handling systems) 82,000 or more 25,000–81,999 Less than 25,000
The categorization of CAFOs affects whether a facility is subject to regulation under the Clean Water Act (CWA). EPA's 2008 rule specifies that "large CAFOs are automatically subject to EPA regulation; medium CAFOs must also meet one of two 'method of discharge' criteria to be defined as a CAFO (or may be designated as such); and small CAFOs can only be made subject to EPA regulations on a case-by-case basis." A small CAFO will also be designated a CAFO for purposes of the CWA if it discharges pollutants into waterways of the United States through a man-made conveyance such as a road, ditch or pipe. Alternatively, a small CAFO may be designated an ordinary animal feeding operation (AFO) once its animal waste management system is certified at the site.
Since it first coined the term, the EPA has changed the definition (and applicable regulations) for CAFOs on several occasions. Private groups and individuals use the term CAFO colloquially to mean many types of both regulated and unregulated facilities, both inside and outside the U.S. The definition used in everyday speech may thus vary considerably from the statutory definition in the CWA. CAFOs are commonly characterized as having large numbers of animals crowded into a confined space, a situation that results in the concentration of manure in a small area.
Key issues Environmental impact
The EPA has focused on regulating CAFOs because they generate millions of tons of manure every year. When improperly managed, the manure can pose substantial risks to the environment and public health. In order to manage their waste, CAFO operators have developed agricultural wastewater treatment plans. The most common type of facility used in these plans, the anaerobic lagoon, has significantly contributed to environmental and health problems attributed to the CAFO.
Water quality The large amounts of animal waste from CAFOs present a risk to water quality and aquatic ecosystems. States with high concentrations of CAFOs experience on average 20 to 30 serious water quality problems per year as a result of manure management issues.Animal waste includes a number of potentially harmful pollutants. Pollutants associated with CAFO waste principally include: nitrogen and phosphorus, collectively known as nutrient pollution; organic matter; solids, including the manure itself and other elements mixed with it such as spilled feed, bedding and litter materials, hair, feathers and animal corpses; pathogens (disease-causing organisms such as bacteria and viruses); salts; trace elements such as arsenic; odorous/volatile compounds such as carbon dioxide, methane, hydrogen sulfide, and ammonia; antibiotics; pesticides and hormones.U.S. Environmental Protection Agency (EPA). "National Pollutant Discharge Elimination System Permit Regulation and Effluent Limitations Guidelines and Standards for Concentrated Animal Feeding Operations." Federal Register, (proposed Jan. 12, 2001). See also: Preamble to the Final Rule at 7181.
The two main contributors to water pollution caused by CAFOs are soluble nitrogen compounds and phosphorus. The eutrophication of water bodies from such waste is harmful to wildlife and water quality in aquatic system like streams, lakes, and oceans.Doug Gurian-Sherman. April 2008. CAFOs Uncovered: The Untold Costs of Confined Animal Feeding Operations , Union of Concerned Scientists, Cambridge, MA.
Groundwater and surface water are closely linked, so polluting one often affects the other. Surface water may be polluted by CAFO waste through the runoff of nutrients, organics, and pathogens from fields and storage. Waste can be transmitted to groundwater through the leaching of pollutants.MacDonald, J.M. and McBride, W.D. (2009). The transformation of U.S. livestock agriculture: Scale, efficiency, and risks. United States Department of Agriculture. Some facility designs, such as lagoons, can reduce the risk of groundwater contamination, but the microbial pathogens from animal waste may still pollute surface and groundwater, harming wildlife and human health.e.g., Burkholder et al. 1997; Mallin 2000
A CAFO is responsible for one of the biggest environmental spills in U.S. history. In 1995, a lagoon ruptured in North Carolina. North Carolina contains a large portion of the United States' industrial hog operations, which disproportionally impact Black, Hispanic and Indian American residents. The spill released of effluvium into the New RiverInstitute of Science, Technology and Public Policy, Maharishi University of Management, Assessment of Impacts on Health, Local Economies, and the Environment with Suggested Alternatives and killed 10 million local fish. The spill also contributed to an outbreak of Pfiesteria piscicida, which caused health problems in nearby humans, including skin irritation and short-term cognitive problems.
Air quality CAFOs reduce ambient air quality. They release several gases harmful to humans: ammonia, hydrogen sulfide, methane, and particulate matter. Larger CAFOs release more gas, mostly by the decomposition of large stores of animal manure. CAFOs also emit strains of antibiotic resistant bacteria into the surrounding air, particularly downwind. Levels of antibiotics measured downwind from swine CAFOs were three times higher than those measured upwind. The source is not widely known, but animal feed is suspected.Globally, ruminant livestock are responsible for about 115 Tg/a of the 330 Tg/a (35%) of anthropogenic greenhouse gas emissions released per year."Trace Gases: Current Observations, Trends, and Budgets" , Climate Change 2001, IPCC Third Assessment Report. IPCC/United Nations Environment Programme Livestock operations are responsible for about 18% of greenhouse gas emissions globally and over 7% of greenhouse gas emissions in the U.S.David N. Cassuto, The CAFO Hothouse: Climate Change, Industrial Agriculture and the Law Methane is the second most concentrated greenhouse gas contributing to global climate change,EPA (1999). "U.S. methane emissions 1990–2020: Inventories, Projections, and Opportunities for Reduction." EPA 430-R-99-01. with livestock contributing nearly 30% of anthropogenic methane emissions.H. Augenbraun Augenbraun, H., Matthews, E., & Sarma, D. (1997). "The Global Methane Cycle" Only 17% of livestock-related emissions come from manure, whereas most come from enteric fermentation or gases produced during digestion. 76% of bacteria grown within a swine CAFO are Staphylococcus Aureus, followed by Group A Streptococci and Fecal Coliforms.
The Intergovernmental Panel on Climate Change (IPCC) acknowledges the big effect of livestock on methane emissions, antibiotic resistance, and climate change. To reduce emissions, it recommends removing sources of stress and changing how animals are fed, including sources of feed grain, amount of forage, and amount of digestible nutrients.B. Metz Metz, B., Davidson, O., Bosch, P., Dave, R., & Meyer, L. (Eds.) (2007). Chapter 8: Agriculture. In IPCC Fourth Assessment Report: Climate Change 2007, "Mitigation of Climate Change". Cambridge, UK: Cambridge University Press. The Humane Society of the United States (HSUS) argues for reducing use of non-therapeutic antibiotics, especially those that are widely used in human medicine, on the advice of over 350 organizations including the American Medical Association. If no change is made and methane emissions continue increasing in direct proportion to the number of livestock, global methane production is predicted to increase by 60% by 2030.Kumar, S., Puniya, A.K., Puniya, M., Dagar, S.S., Sirohi, S.K., Singh, K., Griffith, G.W. (2009). "Factors affecting rumen methanogens and methane mitigation strategies". World J. Microbiol Biotechnol, 25:1557–1566 Greenhouse gases and climate change make air worse, causing illnesses such as respiratory disorders, lung tissue damage, and allergies. Reducing the increase of greenhouse gas emissions from livestock could rapidly curb global warming.McMichael, A. J., Powles, J. W., Butler, C. D., & Uauy, R. (2007). "Food, livestock, production, energy, climate change, and health". The Lancet, 1253–1263 Also, people near CAFOs often complain of the smell, which comes from a complex mixture of ammonia, hydrogen sulfide, carbon dioxide, and volatile and semi-volatile organic compounds.
Waste disposal also makes air worse. Some CAFOs will use "spray fields" and pump the waste of thousands of animals into a machine that sprays it onto an open field. The spray can be carried by wind onto nearby homes, depositing pathogens, heavy metals, and antibiotic resistant bacteria into the air of poor or minority communities. It often contains respiratory and eye irritants including hydrogen sulfide and ammonia.
Economic impact
Increased role in the market The economic role of CAFOs has expanded significantly in the U.S. in the past few decades, and there is clear evidence that CAFOs have come to dominate animal production industries. The rise in large-scale animal agriculture began in the 1930s with the modern mechanization of swine slaughterhouse operations.