Dry Basis

Values in this column give the nutrient values with the water removed.  This allows comparisons to be made between forages.  This is the best indicator of nutrient value because forages are evaluated on a dry matter basis.

Crude Protein

The measure of the nitrogen content of a forage is used to calculate the crude protien content as follows: CP = %N x 6.25.  Crude Protein will include both true protein and non-protein nitrogen.  Crude Protein values give no indication if heat damage has occurred.

Heat Damaged Protein

The measure of protein determines if a % was damaged or bound due to excessive heat.  This is most commonly found in haylages.

Unavailable Protein

A forage report will not always show this value unless heat damage has occurred.  This value will give an indication if excessive heating has occurred, reducing the protein digestibility.  All forages have some unavailable protein.

Available Protein

In some reports this value will be the difference between the crude protein and unavailable protein value.  However, some laboratories account for the naturally bound protein found in forages.

Soluble Protein 

This is protein which is rapidly degraded to ammonia in the rumen and reported as % of crude protein.  Some of this rapidly available protein is needed by the rumen bacteria when their growth is high.

Acid Detergent Fiber (ADF)

The ADF value refers to the cell wall portions of the forage that are made up of cellulose and lignin.  These values are important because they relate to the ability of an animal to digest the forage.  As ADF increases the ability to digest or the digestibility of the forage decreases.

Neutral Detergent Fiber (NDF)

The NDF value is the total cell wall which is comprised ot the ADF fraction plus hemicellulose.  NDF values are important because they reflect the amount of forage the animal can consume.  As NDF percent increases, the dry matter intake generally decreases.

Total Digestible Nutrients (TDN)

Some laboratories use the same formula to calculate the TDN value as they do the Digestible Dry Matter (DDM); therefore, the two values would be the same.  Other laboratories will use different formulas, such as:

Net Energy-Lactation, Net Energy-Maintenance and Net Energy-Gain

These net energy values are often calculated from TDN values, which in turn are generated from percent ADF.  Examples are:

Relative Feed Value (RFV)

Relative feed value is an index that combines the important nutritional factors of intake and digestibility.  It has no units, but the index allows for comparisons of legume, grass and legume/grass forages.  A relative feed value is not to be used for nutritional ration balancing.  Instead, it will assist in determining the value of a material for marketing purposes.

Relative Feed Quality (RFQ)

Relative feed quality is calculated by estimating the digestibility of the forage dry matter and by determining how much the cow can eat based on its filling capacity.  The RFQ index uses fiber digestibility to estimate intake as well as the total digestible nutrients (energy) of the forage.  This can be used to more accurately predict the animals' performance and match the animals needs.

Minerals

Wet chemistry processes determine macro minerals as percent and trace minerals as parts per million (ppm).  If the Near Infrared Spectroscopy (NIRS) is used, the test will include only the macro minerals.  The macro minerals include percent calcium, phosphorus, potassium and magnesium.  The use of wet chemistry will if requested include iron as ppm, copper, zinc and manganese.

Fat

These are the oils and related compounds found in grains and forages that naturally make-up approximately 2-4 percent of the ration.

Ash

This represents the mineral content of the feed or forage.  Forages contain 3 to 12 percent ashes on a dry weight basis while grains and concentrates contain 1 to 4 percent.

Lignin

Lignin is the prime factor influencing the digestibility of plant cell wall material.  As lignin increases, the digestibility, intake and animal performance usually decreases.  As the percent of lignin increases, the percentage of ADF and NDF also increases in forage.

Starch

Starch is classified as a carbohydrate or non-structural in definition.  Carbohydrates reside within the cell or contents and their digestibility is about 90 percent.