scope:

Purpose 

This standard provides three types of information for estimating characteristics of livestock and poultry manure:

• Typical characteristics for manure "as-excreted" by livestock and poultry based on typical diets and animal performance levels in 2002 (Section 3);
• Equations for estimating manure excretion characteristics based on animal performance and dietary feed and nutrient intake specific to an individual situation (Sections 4 through 9);
• Typical characteristics for manure "as-removed" from manure storage or animal housing (Section 10). 

Typical or average estimates of manure excreted become obsolete due to changes in animal genetics, performance potential, feeding program strategies, and available feeds. To minimize future concerns, a set of equations for predicting nutrient excretion (primarily nitrogen and phosphorus), dry matter, and, depending upon species, other potential characteristics have been assembled for beef, dairy, swine, horses and poultry. The Equation Estimates sections (Sections 4 through 9) allow an estimate of manure characteristics that is relevant to a wide range of dietary options and animal performance levels commonly observed in commercial production. 

It is more appropriate to use the equations in Sections 4 through 9for the following situations:

• When comprehensive nutrient management plans are being developed specific to an individual animal feeding operation (AFO);
• When farm specific data is available for an AFO's feeding program and animal performance;
• When feed intake, feed nutrient concentration, feed digestibility, or animal performance varies from the assumptions used to estimate the typical values in Table 1.
• When Table 1 has not been updated to address industry trends.

It may be more appropriate to use the typical values found in Table 1 for the following situations:

• When planning estimates are being made on a scale larger than a single farm (e.g. county or regional estimate of nutrient excretion)
• When a rough approximation is needed for farm planning;
• When farm-specific information of animal performance and feed intake is not available.

Section 3. Typical As-Excreted Manure Production and Characteristics. The user of these data should recognize that the reported typical values may become obsolete with time due to changes in animal genetics, feeding programs, alternative feeding technologies, and available feeds. In addition, users should also recognize that under current conditions, excretion of nutrients and other related characteristics will vary for individual situations from the currently listed values due to variations in animal feed nutrient intake, animal performance, and individual farm management. Sections 4-9 provide an alternative, and often more accurate, methodology for estimating nutrient excretion for individual production systems. 

Sections 4 - 9. Equations for As-Excreted Manure Characteristics Estimates for Individual Species. These sections demonstrate the impact of dietary changes on nutrient excretion. However, this is not intended to be used as a ration-balancing tool, nor is this the appropriate tool for estimating the nutrient needs of the animal. Nutrient needs are best defined in the National Research Council's publication series or by using University recommendations. Both sources of information can provide estimates that reflect biological inefficiencies and digestibility limitations.

In using Sections 4 - 9 to evaluate the impact of alternative rations, it is important to recognize that these equations accurately estimate excretion only when animals are fed diets that meet or exceed the animal's minimum nutrient requirements. Estimates of excretion based on dietary options that do not meet an animal's minimum needs will not be accurate. Sections 4-9 are to be used following ration development by an animal nutrition professional. 'New research data on excretion will be of value for confirming or improving the accuracy of the equations estimating excreting. The authors of this standard are very interested in comparing new research data with these equations. Authors can be contacted through the ASAE Standards staff.

Section 10. Typical As-Removed Manure Production and Characteristics. Many physical, chemical, and biological processes can alter manure characteristics from its original as-excreted form. The as-removed manure production and characteristics values reported in this table allow for common modifications to excreted manure (Section 3) resulting from water addition or removal, bedding addition, and/or treatment processes. These values represent typical values based on available data sources (see end of Section 10). These estimates may be helpful for individual farm long-term planning prior to any samples being available and for planning estimates addressing regional issues. Whenever possible, site-specific samples or other more localized estimates should be used in lieu of national tabular estimates. This table should not be used to develop individual year nutrient management plans for defining field specific application rates, unless absolutely no site-specific manure analysis data are available. However, where site-specific data are unavailable, this table may provide initial estimates for planning purposes until those site specific values are available.