This fact sheet has been developed to support the implementation of the Natural Resources Conservation Service Feed Management 592 Practice Standard. The Feed Management 592 Practice Standard was adopted by NRCS in 2003 as another tool to assist with addressing resource concerns on livestock and poultry operations. Feed management can assist with reducing the import of nutrients to the farm and reduce the excretion of nutrients in manure.
The Natural Resources Conservation Service has adopted a practice standard called Feed Management (592) and is defined as “managing the quantity of available nutrients fed to livestock and poultry for their intended purpose”. The national version of the practice standard can be found in a companion fact sheet entitled An Introduction to Natural Resources Conservation Service (NRCS) Feed Management Practice Standard 592. Please check in your own state for a state-specific version of the standard.
Mass balance is calculated as the difference between imported and exported mass across the farm boundary. Estimating mass balance can provide critical information for (comprehensive) nutrient management planning and to manage the movement of nutrients and manure. Estimation of whole-farm P mass balance is used to determine the acres of land needed for crop production to use manure P. Environmental risk to surface and ground waters is increased if the amount of P imported into the farm (e.g., from fertilizers, feeds, and animals) exceeds the amount of P exported from the farm (e.g., crops, animals, manure, milk, meat, eggs, and fibers).
In Table 1 are estimates of P excretion derived by mass balance calculations using standard diets, animal performance, and the acres needed for land application at a crop removal rate of 50 pounds P2O5/acre per year. Mass balance estimates vary among farms, depending upon specific inputs and outputs, and should be calculated specifically for each farm when doing nutrient management planning.
|Livestock Enterprise||Pounds P2O5||Acres needed|
|Lactating dairy cows||86,000||1,720|
|Swine breeding herd with phytase||37,000||740|
|Swine growing-finishing with phytase||3,600||72|
|Turkeys with phytase||1,300||26|
Farms may consider moving manure off site to reduce P mass balance if not enough acreage is available. Additionally, potential feeding strategies to reduce P balance (and excretion), feed costs, and necessary land base include the following:
National Research Council. 2001. Nutrient Requirements of Dairy Cattle. 7th rev. ed. Natl. Acad. Sci., Washington, DC.
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This fact sheet reflects the best available information on the topic as of the publication date. Date 5-25-2007
This Feed Management Education Project was funded by the USDA NRCS CIG program. Additional information can be found at Feed Management Publications.
This project is affiliated with the LPELC.
Brian Perkins - Consulting Nutritionist
Katherine Knowlton - Virginia Tech