CAFO Glossary

Glossary of CAFO Terms

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Algae are aquatic plants, tiny suspended or attached green slimy materials in water. The excessive nutrients in CAFO pollution stimulate enhanced growth in algae (called an algal bloom).  The algae cycle quickly through a growth and death process that can reduce dissolved oxygen in the water and cause fish kills. This process is called eutrophication and severely degrades water quality.

Animal Sector Descriptions

Poultry, swine, dairy, and beef are the four principle sectors described in this U.S. EPA document (pdf).

Animal Feeding Operation (AFO)

A lot or facility, other than an aquatic animal production facility, where the animals, other than aquatic animals, have been, are, or will be stabled or confined and fed or maintained for a total of 45 days or more in any 12-month period, and crops, vegetation, forage growth, or post-harvest residues are not sustained in the normal growing season over any portion of the lot or facility.

Biological Oxygen Demand (BOD)

Indicates the presence of silage leachate and milk wastes by measuring the amount of oxygen taken up by microorganisms that are decomposing the waste.  When BOD levels are high, then dissolved oxygen levels decrease because the oxygen dissolved in the water is being consumed by the bacteria.  See this article for more information about BOD.   See this information on Michigan's water quality parameters and standards.

CAFO (Concentrated Animal Feeding Operation)

CAFO is a commonly used acronym for concentrated animal feeding operation.  It is an AFO (see description above) that is defined as a large CAFO or a medium CAFO, or that is designated by the Michigan DEQ under R 323.2196 (3) as a medium CAFO or a small CAFO.  (An AFO may be designated as a CAFO, even if the operation has a smaller number of animals, if they have had a discharge to waters of the state that caused those waters to not meet water quality standards.) 

Two or more AFOs under common ownership are considered to be a single AFO for the purposes of determining the number of animals at an operation, if they adjoin each other or if they use a common area or system for the disposal of wastes.

A Large CAFO is an AFO that stables or confines as many as or more than the numbers of animals specified in any of the following categories:

  • 700 mature dairy cows, whether milked or dry
  • 1,000 veal calves 1,000 cattle (other than mature dairy cows or veal calves), including heifers, steers, bulls, and cow/calf pairs
  • 2,500 swine, each weighs 55 pounds or more
  • 10,000 swine, each weighs less than 55 pounds
  • 500 horses
  • 10,000 sheep or lambs
  • 55,000 turkeys
  • 30,000 laying hens or broilers, if the AFO uses a liquid manure handling system
  • 125,000 chickens (other than laying hens), if the AFO doesn't use a liquid manure handling system
  • 82,000 laying hens, if the AFO doesn't use a liquid manure handling system
  • 30,000 ducks, if the AFO does't use a liquid manure handling system
  • 5,000 ducks, if the AFO uses a liquid manure handling system
Catch Basin

- see Tile Risers and Catch Basins

CNMP (Comprehensive Nutrient Management Plan)

In some documents, the CNMP is referred to as a Nutrient Management Plan, or NMP. Intended to help protect water quality, a CNMP is a plan for managing all the nutrients in animal manure from an entire CAFO. The written document includes plans for manure handling, transfer, and storage; for spreading manure on cropland; land management and record keeping; feed management, and other options such as composting of the manure waste. The plan also lists fields that will be used for land application of the manure, and spells out emergency actions to be taken in case of a spill.  Because the CNMP is a plan for nutrient management, it is not intended to manage pathogens from CAFOs.  However, properly written and implemented, a CNMP should also help a CAFO keep pathogens from entering waters of the state.

Consent Order

An order made by the court based upon the agreement of the parties.

Contaminated Stormwater

Rain that falls from the sky is considered clean, and no special measures are required for its disposal or placement. If the clean stormwater is allowed to flow across contaminated or dirty surfaces, or to mix with manure, or to flow through a silage or compost pile (and create leachate), then it must be treated as dirty water, and added to the waste storage structures or treated prior to discharge. It is to the CAFO's advantage to keep rain water clean and away from the production area of the CAFO because it then needs no special treatment.  


A means by which water flows or is transferred from one point to another.  It may be a pipe, a storm drain, a field-tile drainage system, a catch basin, or a county drain, etc. 

County Drains and Creeks

In Michigan County Drains are under the jurisdiction of a Drain Commissioner, who is subject to Michigan's Drain Code of 1956.  Similar concerns exist with these waterways as with ditches, but these are also considered waters of the state of Michigan. There are concerns that placing facilities too close to either of the receiving waters increases the chance of discharges. CAFOs have been found to have run drainage tiles from the barns, lagoons, milkhouses or other production areas directly into county drains or streams to discharge wastes. In addition, some county drains are located underground, and some CAFOs have actually built lagoons on top of the drains. Underground drains also can provide a conduit for liquid wastes traveling through the soil after being applied to fields.


An embankment for controlling or holding back water.


A discharge is any direct or indirect release of any waste, waste effluent, wastewater, pollutant, or any combination thereof into any of the waters of the state or upon the ground.

Dissolved Oxygen (DO)

Dissolved oxygen is important for fish and their food organisms. The Michigan water quality standard for DO in warm water is 5mg/l (5 milligrams of dissolved oxygen per liter of water). Many kinds of pollution from CAFOs and other sources can reduce DO levels, and if the levels drop to 3mg/l or below, then fish kills can occur.   See this article from for more information on DO.  See this information on Michigan's water quality parameters and standards.

Dissolved Oxygen Meter (DO Meter)

A DO meter uses a probe placed into the water to measure its concentration of dissolved oxygen, as well as water temperature.  Measuring DO in waters both upstream and downstream of a pollution source can pinpoint problems.  Finding different water temperatures upstream and downstream can signal problems, too, such as water warmed on a field then pouring off the surface or through a pipe into a drain or a stream.

Escherichia coli or E. coli

A specific fecal coliform found in the gut of all animals including humans, its presence in water indicates pollution from animal wastes. Many states now have a numerical state standard for E. coli in surface water. Fecal coliform tests may also be conducted when E.coli testing is not available (on weekends and holidays most DEQ certified labs are closed.)

EQIP (Environmental Quality Incentives Program)

A federal program that pays farmers to take measures to prevent some of the environmental damage they cause, and to preserve wildlife habitat.  See this factsheet (pdf) from the U.S.D.A. for more information.


Often countryside air has an odor of manure, that some people associate with being out in farmland.  Generally, an odor will not make you ill.  But air emissions of gases and pollutants from CAFOs can cause headache, nausea, burning sinuses, and sore throat.  Severe or frequent exposures to hydrogen sulfide (H2S), one of several different substances, can cause neurological problems, including depression, anger, and memory problems.  See Ohio State University's fact sheets  Understanding Air Emissions from Animal Feeding Operations and Ammonia emission from animal feeding operations.

An air emission is “any physical, chemical, biological or radioactive substance or matter that is emitted into the ambient air surrounding a property and contains air pollutants”, as defined in Section 302 of the Clean Air Act, as amended, 42 U.S.C, 7602. The air emission rate indicates how much air pollutant emissions are emitted into the ambient air within a certain time period. Air emissions directly affect the environment and potentially degrade air quality and may thereby affect health.


The degradation of a body of water due to the growth and subsequent death of vegetation that lowers oxygen content as it decays, killing fish and other aquatic organisms. Excess nutrients (nitrogen and/or phosphorus) from overuse of fertilizers and other sources causes the problem.  CAFOs often cause eutrophic conditions in receiving waters that are downstream. 

Externalized Costs

Health or environmental costs that are placed on society instead of the responsible party.

Farm Bill

A package of federal laws that is renewed every five years that creates U.S. agriculture policy and spending priorities.

Fecal Bacteria

See E. coli.

Field Tile

A field tile is a subsurface drainage system of perforated pipe, a practice used to remove excess water from the surface and subsurface of soil intended for agriculture. Field Tiles usually drain underground horizontally directly to a ditch, and so are often a conduit for contaminated water to reach waters of the state (lakes, rivers, streams, groundwater, wetlands, etc.).  Many decades ago, field tiles were made of heavy ceramic, hence the name field "tile".  Most of wet lower Michigan's fields are underlain with field tiles.  The use of field tiles made crop agriculture possible in Michigan, because fields had to be drained in order to be usable.   

Freedom of Information Act (FOIA)

Many states have Freedom of Information Acts (FOIA) or Open Records Acts which require the state to provide access to all files they hold. There may be fees associated with the cost of copying the files, or you may be able to visit the agency’s offices and review the files on site before asking for copies. Michigan’s FOIA statute is one example. Contact your state agency and request information about their requirements.

The US EPA and all other federal agencies are subject to the federal Freedom Of Information Act. The Act allows for the full or partial disclosure of previously unreleased information and documents controlled by the United States government. The Act defines agency records subject to disclosure, outlines mandatory disclosure procedures and grants nine exemptions to the statute. The acronym is often used as a verb, as in "You need to FOIA those documents."

GAAMPs (Generally Accepted Agriculture Management Practices)

The Michigan Right to Farm Act, P.A. 93, was enacted in 1981 to provide farmers with protection from nuisance lawsuits. The statute authorizes the Michigan Commission of Agriculture to develop and adopt GAAMPs, voluntary practices, based on available technology and scientific research to promote sound environmental stewardship, that if they are followed, will help maintain a farmer's right to farm.

Indirect Subsidy

Business support received resulting from direct subsidies paid to another party.

Injection Systems

CAFOs will sometimes “inject” waste into the soil through the use of chisel blades or other devices pulled behind tractors or trucks. Injection of waste into the soil will reduce surface run-off and is intended to reduce odors from waste applied to the surface of the fields. However, injected waste may flow more quickly into field tiles or groundwater.

Integration (also known as Vertical Integration)

Control and ownership by a single entity over multiple stages of production through ownership or contract arrangements.


Open-air pits, lagoons are waste-storage structures the size of football fields or larger that store millions of gallons of waste from CAFOs. Most Michigan CAFOs must have capacity to store 6 months' worth of manure and animal waste, and some even more, due to Michigan's long winter season.  CAFOs tend to empty their lagoons, by land-applying the stored animal waste, in late fall and spring, making these times some of the worst for air quality for CAFO neighbors. 

Mad Cow Disease

Mad Cow Disease refers to Bovine spongiform encephalopathy (BSE), a chronic, degenerative disorder affecting the central nervous system of cattle.   Similar to BSE, Creutzfeldt-Jakob disease (CJD) is a rare disease that occurs in humans. In 1996, following outbreaks of BSE among British cattle, scientists found a possible link between BSE and a new variant of CJD (vCJD). While it is not certain how BSE may be spread to humans, evidence indicates that humans may acquire vCJD after consuming BSE-contaminated cattle products.  See this Food and Drug Administration webpage for more information.


Manure is defined to include animal feces and urine, bedding, compost, and raw materials or other materials commingled with manure or set aside for disposal. Read more about CAFO manure in What is in CAFO manure?

Manure Irrigators

Waste sprayed onto farm fields through irrigation equipment can cause contamination in several ways, from directly spraying wastes into waterways, from broken hoses spewing wastes onto the field, and from over-application. There are several types of irrigation, including: travel irrigators, pivot irrigators, gun irrigators, and sub-irrigation.


Michigan Department of Agriculture


Michigan Department of Community Health


Michigan Department of Environmental Quality


Michigan Department of Natural Resources

MAEAP (Michigan Agriculture Environmental Assurance Program)

MAEAP is a voluntary, pro-active program designed by state and federal agencies, farmers and industry partners to reduce producers' legal and environmental risks. It teaches effective land stewardship practices that comply with state and federal regulations and shows producers how to find and prevent agricultural pollution risks on their farms. 


The Michigan Manure Application Risk Index is based upon evaluating a field for manure runoff potential after an application is made on snow covered or frozen soil. Here's an example evaluation spreadsheet.

Methane Digester

Methane digesters are anaerobic (low or no oxygen) chambers which facilitate the breakdown of manure by anaerobic bacteria with the release of methane and other gases as a byproduct of their metabolism, including ammonia,  nitrogen, hydrogen sulfide, and sulfur dioxide.  Methane can be burned directly in stoves or burners, to heat the digester, and it can be converted to electricity.  There are several different types of systems but all commercially available systems are expensive to install and require manure from a large number of animals to operate.

Most environmental damage caused by CAFO wastes remains unabated. Excess nutrients still exist, the volume of solid waste remaining is not significantly diminished and still requires proper disposal. Anaerobic digestion does not remove antibiotics and heavy metals from manure.  Although pathogen numbers may decrease, the decrease may be ephemeral as the pathogens regrow.  See this Sierra Club Guidance factsheet for more information.

Milkhouse Wastes

This can include anything from bad milk, or milk that was contaminated and cannot be sold, to the chemicals and cleaners used to sanitize the milking parlor.  If a ditch near a dairy CAFO appears to be filled with white liquid, it may be milkhouse waste.  Milkhouse wastes are a huge source of nutrients, and can cause degraded water conditions if allowed to reach surface water.  See Nutrients.

Nitrogen or Nitrates

Nitrogen is an element needed by all living plants and animals to build protein. In aquatic ecosystems, nitrogen is present in many forms. It can combine with oxygen to form a compound called nitrate.  Nitrates may come from fertilizers, sewage, and industrial waste. They can cause eutrophication of lakes or ponds. Here's an excellent primer.  Also see Michigan's water quality parameters and standards.

NPDES (National Pollution Discharge Elimination System)

The Clean Water Act pollution control water discharge permit system that:

  1. names specific pollutants with amounts and limits that may be discharged from a site such as a waste water treatment plant or a CAFO,
  2. sets rules for water discharge permit issuance, and
  3. establishes regulations for monitoring, reporting requirements, and enforcement. The Michigan DEQ received delegated authority from the US EPA to run the federal program.
No Till

No Till is a method of growing crops without tilling the soil.  It's a more common practice with GMO crops (genetically modified) or Bt crops (grown with natural insecticide produced by the bacterium Bacillus thuringiensis .) No till crops need more chemical usage than traditional tilling because soil is not broken up prior to planting.

Nuisance Lawsuit

A nuisance lawsuit usually entails a neighbor suing a livestock or animal product producer to stop a harmful farming activity or force payment of damages for harmful farming actions. The lawsuit starts when a neighbor cannot enjoy or use their property because of the CAFO's activities next door.

Nutrient Management Plan (NMP) (see CNMP)

Nitrogen and Nitrates and phosphorus and phosphates are plant nutrients.  CAFOs have many sources of plant nutrients, including manure, milkhouse wastes, and compost and silage leachate.  When excess nutrients make it to surface waters, they often cause algae blooms and other dangerous conditions. 

Open Ditches

Most CAFOs have open ditches within 500 feet of the facilities, and some have ditches immediately adjacent to the buildings. Fields that are land-applied with animal waste have ditches either next to them or running through them.  There are even some CAFOs with buried waterways directly below the facilities themselves. Ditches connect to surface waters, and may have field tiles connected to them directly from the facility.

Open Records Search

(see FOIA)

PEAS (Pollution Emergency Answering System)

The PEAS Hotline is available 24 hours a day in case of environmental emergency affecting AIR - LAND - WATER.  If necessary, callers can remain anonymous.   

Call:   1-800-292-4706 (in Michigan)

The PEAS hotline should be used to report environmental pollution emergencies such as tanker accidents, pipeline breaks, and releases of reportable quantities of hazardous substances as required.  The phone number rings into an answering service which is staffed 24 hours a day. Between 8 a.m. and 5 p.m. on normal working days (Monday-Friday) the operator will give callers the option of contacting the appropriate Department of Environmental Quality (DEQ) district office serving the area where an incident has occurred, or the operators will take the information and dispatch the calls to the district offices for the caller.


(see also NPDES)
This document gives permission to discharge some pollutant(s), spelling out quantities or concentrations, and specific conditions under which the discharge may occur into water or air. National Pollutant Discharge Elimination System Water discharge permits are governed by the Clean Water Act, and air quality permits by the Clean Air Act.

pH of water

The MDEQ's water quality standard document for pH (PDF) states, "Most aquatic plants and animals are adapted to a specific pH range, and natural populations may be harmed by water that is too acidic or alkaline. Immature stages of aquatic insects and young fish are extremely sensitive to pH values below 5. Even microorganisms which live in the bottom sediment and decompose organic debris cannot live in conditions which are too acidic. In very acidic waters, metals which are normally bound to organic matter and sediment are released into the water. Many of these metals can be toxic to fish and humans. Below a pH of about 4.5, all fish die."  See more information on Michigan's water quality parameters and standards

Phosphorus or Phosphates

Phosphorus is usually present in natural waters as phosphate. Phosphates are present in fertilizers and can enter the water from agricultural runoff, industrial waste, and animal and human sewage. Phosphates, like nitrates, are plant nutrients. When too much phosphate enters the water, plants flourish.  Phosphates also stimulate the growth of algae which can result in an algae bloom.  As the plants and algae grow, they choke out other organisms, leading to nuisance conditions. See DEQ information on Harmful Algal Blooms.  See more information on Michigan's water quality parameters and standards.


Prion diseases or transmissible spongiform encephalopathies (TSEs) are a family of rare progressive neurodegenerative disorders that affect both humans and animals.  See the Center for Disease Control and Prevention webpage on prions.

Production Area

"Production area” means that part of an AFO that includes animal confinement area, manure storage area, raw materials storage area, and waste containment areas. The animal confinement area includes open lots, housed lots, feedlots, confinement houses, stall barns, free stall barns, milk rooms, milking centers, cowyards, barnyards, medication pens, walkers, animal walkways, and stables.

The manure storage area includes lagoons, runoff ponds, storage sheds, stockpiles, under house or pit storages, liquid impoundments, static piles, and composting piles. The raw materials storage area includes feed silos, silage bunkers, and bedding materials. The waste containment area includes settling basins and areas within berms and diversions which separate uncontaminated storm water. Also included is any egg washing or egg processing facility, and any area used in the storage, handling, treatment, or disposal of mortalities. (e) “Production area waste” means manure and any waste from the production area and any precipitation (e.g., rain or snow) which comes into contact with, or is contaminated by, manure or any of the components listed in the definition for “production area.” Production area waste does not include water from land application areas."


Pumps can serve a legitimate purpose at a CAFO, particularly to move wastes from the livestock confinement areas into waste storage lagoons. However, permanent pumps installed at catch basins or portable pumps with hoses signal a potentially inappropriate use. Pumps have been used to illegally pump wastes into tiles, into drains, or into woods or wetlands.

Receiving Water

The natural water body, such as a stream or lake, into which effluent or runoff flows, or that ditches or drains flow to.

Right to Farm Act

(see also GAAMPs)

See the Michigan Department of Agriculture Right to Farm webpage

The Michigan Right to Farm Act, P.A. 93, was enacted in 1981 to provide farmers with protection from nuisance lawsuits. This state statute authorizes the Michigan Commission of Agriculture to develop and adopt Generally Accepted Agricultural and Management Practices (GAAMPs) for farms and farm operations in Michigan. These voluntary practices are based on available technology and scientific research to promote sound environmental stewardship and help maintain a farmer's right to farm.

Silage and Silage Leachate

Silage is fermented, high-moisture fodder that can be stored and fed to ruminants (cud-chewing animals like cattle and sheep). Silage leachate forms when water is allowed into the silage and it washes through the decomposing materials. If the leachate is not contained, it can get into water, bringing with it enormous amounts of nutrients, causing algae blooms, and decreases in dissolved oxygen.


Farmland that liquid animal waste is applied to (spread on), most likely in close proximity to an animal waste storage structure. This may include travel irrigation, gun irrigation, sub-irrigation, tractor and tanker application, drag-line application, and semi truck application.


Stormwater can be rainwater, clean roof runoff.  It should never be contaminated with animal waste.


Payments or compensation for producers for low market prices creating artificial support for an industry to offset its cost for production.

Surface Water(s)

Surface waters are those on the surface of the Earth, such as drains, ditches, streams, rivers, lakes, oceans. Generally, these also describe "waters of the state".

Suspended Solids, also called Total Suspended Solids (TSS)

Total suspended solids (TSS) include all particles suspended in water that will not pass through a filter. Suspended solids are present in sanitary wastewater and many types of industrial wastewater. There are also nonpoint sources of suspended solids, such as soil erosion from agricultural and construction sites.  As levels of TSS increase, a water body begins to lose its ability to support a diversity of aquatic life. Suspended solids absorb heat from sunlight, which increases water temperature and subsequently decreases levels of dissolved oxygen (warmer water holds less oxygen than cooler water). Some cold water species, such as trout and stoneflies, are especially sensitive to changes in dissolved oxygen.   See more information on Michigan's water quality parameters and standards.

Tile Risers and Catch Basins

Both of these are entry points for wastes to be discharged into field tiles and then to surface waters. Tile risers are located in low areas in fields so all water flows into them in order to more quickly drain fields. In fields, application of wastes is supposed to be substantially set back from tile risers to prevent discharges. Catch basins are similar to tile risers but can be larger and more like storm drains found in urban areas. When tile risers and catch basins are placed around buildings and production areas the will drain waste waters run off from the production areas into surface waters. Cement floors are sometimes run at an angle to allow wastes to run directly into catch basins.

Topographic Map (also called Topo Map)

These use lines to represent a general image of the earth's surface, including both natural and human-made features. Contour lines, usually in brown, give indication of shapes and heights of landforms. Blue lines are used for water, displaying connections between ditches, streams, larger rivers, inland lakes, Great Lakes, and the oceans.  Some sources are USGS (free),, or


When the passage of light through water is impeded by sediment, it causes the water to be cloudy. Turbid water absorbs heat, leading to decreased ability to hold oxygen.


Airborne pollutants such as ammonia and other gases are emitted from animal waste.

Waters of the State

Includes drains, ditches, streams, rivers, lakes, all subject to the Clean Water Act.