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Concentrated Animal Feeding Operations

Written by Dr. Zachary J. Miller
Published on February 21, 2023
Research Highlights

Concentrated Animal Feeding Operations (CAFOs) help to meet the growing demand for meat products across the globe.

CAFOs are associated with positive economic benefits for CAFO owners and multi-national meatpacking companies.

The concentration of animals and animal waste in CAFOs can have negative effects on both public health and aquatic ecosystems.

Animal feeding regulations vary by operation size.

Animal feeding operations are categorized by the number of animal units they house. Animal units are based on weight, with one unit equi-valent to about 1,000 lbs. of live animal weight (e.g., one animal unit equals one cow, 2.5 swine, or 100 chickens; EPA 2023).

  • Concentrated animal feeding operations (CAFOs) house at least 1,000 animal units for at least 45 days per year (EPA 2023).
  • As the worldwide demand for meat products increases, CAFOs can be an inexpensive strategy to increase global meat supplies (Godfray 2018, Halweil 2008).

State and federal regulations increase with CAFO size. Animal feeding operations with less than 1,000 animal units are not subject to regulations and do not require permits. There are over 500 registered CAFOs in MO; most are swine or poultry operations (MO DNR 2023).

  • The Dept. of Natural Resources permits CAFOs using an annual renewal process.
  • State CAFO requirements include waste management, new construction notices to neighbors, and other technical standards (DNR 2023).

The economic impact of CAFOs varies by group and region.

There are few studies that investigate the economic costs and benefits of CAFOs across stakeholder groups.

Meat/Dairy Producers and Packagers. CAFO owners and multinational meat-packing companies can leverage economies of scale to reduce costs and maximize profit (Ikerd 1998).

  • CAFOs often outcompete smaller oper-ations. In 2016, only dairy farms with greater than roughly 1,000 cows recorded a net profit (USDA 2020).
  • Most meat produced in a CAFO is a part of a global supply chain and does not enter the local food supply (Weida 2001).

Local Spending and Workforce. Smaller pro-ducers can provide more local economic ben-efits than CAFOs (Weida 2001, Ashwood 2013).

  • 95% of spending for farms earning less than $100,000 per year was spent locally; operations making over $900,000 per year spent less than 20% locally (Weida 2001).
  • Large scale operations often employ fewer workers than smaller operations (Ikerd 1998).
  • CAFOs often rely on immigrant labor and have high turnover rates. CAFO laborers in MO have reported poor working conditions (Ramos 2018).

Homeowners. In several states, including Missouri, property values near CAFOs are 20-40% lower than comparable properties further from CAFOs (Merchant 2018).

CAFOs can negatively impact public health.

The production and management of animal manure in CAFOs can cause several negative health effects.

Collectively, U.S. CAFOs produce more than 40x the amount of biosolid waste than the U.S. population annually (Graham 2010).

  • Manure carries high levels of nutrients (e.g., nitrogen and phosphorus) as well as antibio-tics, hormones, and other contaminants, which are typically flushed into lagoons and recycled in crop fertilizer (Hribar 2010).

Air Quality. Large volumes of manure in CAFOs can decompose and degrade nearby air quality.

Water Quality. Poorly managed manure can overload soil and water (surface and ground) with nutrients and contaminants, negatively impacting drinking water quality (Copeland 2006, Burkholder 2007, Merchant 2018).

  • States with higher concentrations of CAFOs face more water quality problems than those without (Hribar 2010).

Disease Transmission. Intensive animal feed-ing operations such as CAFOs are estimated to have been the origin for 50% of the animal-transmitted diseases that have emerged in human populations (Marchese 2022).

CAFO pollution can harm aquatic ecosystems.

The primary ecological impacts from CAFOs result from excess nutrients and contaminants from manure entering waterways.

Removes oxygen from water. High nitrogen and phosphorus levels in aquatic ecosystems can harm aquatic life by removing oxygen from water (Mallin 2003).

  • In some cases, thousands of fish of multiple species (e.g., minnows, bass, gar, etc.) can die instantly (Burkholder 2007).

Disrupts reproduction and reduces bio-diversity. Antibiotics, hormones, sediment, and nutrients from manure can disrupt the reproduction of some species and reduce the total number of species found in nearby waterways (Burkholder 2007, Merchant 2018).


Ashwood, B. M. (2013). Rural residents for responsible agriculture: Hog CAFOs and democratic action in Illinois. Journal of Rural Social Sciences, 28(3), 4. 

Burkholder, J., Libra, B., Weyer, P., Heathcote, S., Kolpin, D., Thorne, P. S., & Wichman, M. (2007). Impacts of waste from concentrated animal feeding operations on water quality. Environmental health perspectives, 115(2), 308-312. 

Copeland, C., & Resources, Science, and Industry Division. (2006). Animal waste and water quality: EPA regulation of concentrated animal feeding operations (CAFOs). Washington, DC, USA: Congressional Research Service, the Library of Congress. 

Fiala, N. (2008). Meeting the demand: an estimation of potential future greenhouse gas emissions from meat production. Ecological economics, 67(3), 412-419. 

Godfray, H. C. J., Aveyard, P., Garnett, T., Hall, J. W., Key, T. J., Lorimer, J., ... & Jebb, S. A. (2018). Meat consumption, health, and the environment. Science, 361(6399), eaam5324. 

Graham, J. P., & Nachman, K. E. (2010). Managing waste from confined animal feeding operations in the United States: the need for sanitary reform. Journal of water and health, 8(4), 646-670. 

Halweil, B. (2008). Meat production continues to rise. Worldwatch Institute website, 20. 

Heederik, D., Sigsgaard, T., Thorne, P. S., Kline, J. N., Avery, R., Bønløkke, J. H., ... & Merchant, J. A. (2007). Health effects of airborne exposures from concentrated animal feeding operations. Environmental health perspectives, 115(2), 298-302. 

Hribar, C. (2010). Understanding concentrated animal feeding operations and their impact on communities. National Association of Local Boards of Health. Centers for Disease Control.  

Ikerd, John E., “Sustainable Agriculture: An Alternative Model for Future Pork Producers,” in The Industrialization of Agriculture, Jeffrey S. Royer and Richard T. Rogers, eds., Ashgate Press, Brookfield, VT, 1998, pp. 281-283. 

Lee, C. G. (2021). Industrial Animal Agriculture in the Pandemic Spotlight. ABA Tort Trial & Insurance Practice Section Animal Law Committee Newsletter, Winter/Spring. 

Mallin, M. A., & Cahoon, L. B. (2003). Industrialized animal production—a major source of nutrient and microbial pollution to aquatic ecosystems. Population and Environment, 24(5), 369-385. 

Marchese, A., & Hovorka, A. (2022). Zoonoses Transfer, Factory Farms and Unsustainable Human–Animal Relations. Sustainability, 14(19), 12806. 

Merchant, J. A., Naleway, A. L., Svendsen, E. R., Kelly, K. M., Burmeister, L. F., Stromquist, A. M., ... & Chrischilles, E. A. (2005). Asthma and farm exposures in a cohort of rural Iowa children. Environmental health perspectives, 113(3), 350-356. 

Merchant, J. A., & Osterberg, D. (2018). The Explosion of CAFOs in Iowa and Its Impact on Water Quality and Public Health. Iowa Policy Project. 

Sigurdarson, S. T., & Kline, J. N. (2006). School proximity to concentrated animal feeding operations and prevalence of asthma in students. Chest, 129(6), 1486-1491. 

Silbergeld, E. K., Graham, J., & Price, L. B. (2008). Industrial food animal production, antimicrobial resistance, and human health. Annual review of public health, 29(1), 151-169. 

Weida, W. J. (2001). A summary of the regional economic effects of CAFOs. Department of Economics, the Colorado College, Colorado Springs, CO, 21. 

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