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Pacific Southwest, Region 9

Serving: Arizona, California, Hawaii, Nevada, Pacific Islands, Tribal Nations

Animal Waste Terms

Common terms when discussing animal waste:
Cows gathered together in a common feed lot
A typical dairy meets the definition of an Animal Feeding Operation.

Animal Feeding Operation (AFO): A lot or facility where: (1) animals have been, are, or will be stabled or confined and fed or maintained for a total of 45 days or more in a 12-month period; and (2) where crops, vegetation, forage growth, or post harvest residues are not sustained in the normal growing season over any portion of the lot or facility.

Animal Units (AU): A unit of measurement formerly used by EPA and USDA to measure the size of animal feeding operations. An AU is equal to approximately one beef cow. Therefore, 1,000 beef cows equal 1,000 AU. There are multipliers for other types of animal feeding operations.

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Comprehensive Nutrient Management Plans (CNMPs):

The Unified National Strategy for AFOs calls for the NRCS to develop technically sound and economically feasible comprehensive nutrient management plans (CNMPs) for all animal feeding operations. The unified strategy anticipates that for the majority of AFOs, voluntary efforts will be the principle approach to assist owners and operators in developing and implementing CNMPs. However, any CAFO permitted under the National Pollutant Discharge Elimination System (NPDES) would be required to develop and implement a Nutrient Management Plan that includes many of the same components of a CNMP. Key elements of a CNMP include:

  • Feed Management - Where possible animal diets and feed should be modified to reduce the amounts of nutrients in manure.
  • Manure Handling and Storage - Manure needs to be handled and stored properly to prevent water pollution from runoff and to reduce the potential for nutrient release into the air.
  • Land Application of Manure - Land application is the most common, and, if sufficient areas of land exist, an appropriate method of using manure because of the value of the nutrients and organic matter. Land application in accordance with the CNMP should minimize water quality and public health risk.
  • Land Management - Tillage, crop residue management, grazing management and other conservation practices should be used to minimize the movement of soil, organic materials, nutrients and pathogens to surface and ground water from lands where manure is applied.
  • Record Keeping - Feedlot operators should keep records that indicate the quantity of manure produced and ultimate use, including where, when and amount of nutrients applied.
  • Other Options for Manure Use - In vulnerable watersheds, where the potential for environmentally sound land application is limited, alternative uses of manure, such as the sale of manure to other farmers, the composting and sale of compost to homeowners, or using manure for power generation may need to be considered.

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Concentrated Animal Feeding Operation (CAFO): An AFO that is defined or designated as a CAFO based on the number of animals at the facility and/or whether the facility discharges to waters of the United States (WUS). An AFO is defined as a large CAFO if it stables or confines numbers of animals specified in the CAFO rule. For example, an AFO with 700 mature dairy cows qualifies as a CAFO. A medium CAFO is smaller (e.g., 400 mature cows) than a large CAFO and it discharges to WUS. A small CAFO does not have a sufficient number of animals to qualify as a medium CAFO, and it must be designated a CAFO upon a determination that it is a significant contributor of pollutants to a WUS. The prior explanations are a simplification of the definitions for Large, Medium, and Small CAFOs. For the exact definitions, please see 40 CFR 122.23.

Nutrient Management Plan (NMP): is a tool for managing nitrogen and/or phosphorus through best management practices and procedures necessary to implement applicable effluent limitations and standards. A key component of a NMP is the balancing of manure/wastewater nutrients applied to the land with the nutrient needs of the crops grown.

For detailed information, go to: EPA's national CAFO Web site

Nitrate/Nitrite: Nitrogen combined with oxygen forms nitrate. According to EPA's 1992 report to Congress, 49 states identified nitrates as a principal ground water contaminant. Nitrate can contaminate drinking water supplies drawn from ground water. It has been linked to cancer and birth defects. Nitrite may be formed in the stomach by the ingestion of nitrate in drinking water. This can cause the potentially fatal infant disease, methemoglobinemia or "blue baby syndrome".

Nutrients: According to EPA's 1992 report to Congress, the states reported that nutrients and siltation impaired more miles of rivers and streams than any other pollutants. Nutrients are chemical elements, such as nitrogen and phosphorous, that are essential to plant and animal growth. However, excess nutrients in water can degrade water quality by contributing to eutrophication, low levels of dissolved oxygen (anoxia), and toxic algal blooms or other circumstances, have been associated with outbreaks of microbes such as Pfiesteria piscicida.

Nutrient Management Plan (NMP): is a tool for managing nitrogen and/or phosphorus through best management practices and procedures necessary to implement applicable effluent limitations and standards. A key component of a NMP is the balancing of manure/wastewater nutrients applied to the land with the nutrient needs of the crops grown.

For detailed information, go to: EPA's national CAFO Web site

Pathogens: Organisms that pollute drinking water supplies and threaten human health (for example, giardia and cryptosporidium). Pathogens in manure can also create a food safety concern if manure is applied directly to crops at inappropriate times.

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