Acid Detergent Fiber (ADF)

A measure of the cellulose and lignin contents of a plant by boiling a feed in an acid detergent solution. It is inversely related to digestibility, where an increase in ADF will be seen with a decrease of digestibility. ADF is also used to predict energy levels. Factors that can increase ADF are maturity, high temperatures, rain damage, weeds, and weathering. Low levels of ADF are desirable.



The total mineral content of a forage. Ash is calculated by burning the organic matter of a forage and weighing the residue.



Harvested at full length and packaged into rough bales that get wrapped in plastic. This excludes oxygen and leads to fermentation. It is stored between 40-60% moisture.


Carbohydrate (CHO)

Energy providing substrates containing a structural (from plant cell wall) and non-structural (from plant cell contents) fraction. Includes starches, sugars, cellulose, and hemicellulose.



A fibrous carbohydrate that is a major component of plant cell walls.


Component Fed Rations

When forages and grain/supplement are fed separately, with 2-4 grain/supplement feedings per day and forages always available. Typical of tie-stall barns.



Feeds who are high in energy and low in fiber. They are typically categorized as energy and protein concentrates. Examples: corn, barley, etc.



A reduction in size due to a combination of breaking and crushing actions e.g. cracked corn.



In terms of feed, meaning rolled using grooved roller e.g. crimped oats.


Crude Fiber

A measure of the fraction resistant to degradation in acid and alkali. This measure underestimates fiber content, and is typically replaced by ADF and NDF measurements in ruminant diets.


Crude Protein (CP)

The total nitrogen content of the feed multiplied by 6.25. Nitrogen is measured from true protein and NPN. Bacteria in the rumen use CP during digestion.



A measure of how much of a feed or nutrient appears to be digested, expressed as a percentage of the amount of feed or nutrient consumed.



Mechanical, enzymatic, and chemical breakdown of ingested feed for nutrient absorption in the small intestine.


Dry Matter (DM)

The quantity of feed after water is removed. DM contains the nutrients in feed, and in high moisture feed an animal would have to consume more than it would of low moisture feed to meet DM requirements.


Dry Matter Intake (DMI)

The amount of DM consumed.




Derived from digestion, absorption, and metabolism. While the main source of energy is CHO, it can also be derived from lipids.



Also known as structural carbohydrates. Complex carbohydrates that make up the plant cell wall.



Hay that is chopped at harvest before storage. It is a fermented



A polysaccharide found in plant cell walls.



Bound to cellulose, it is a complex polymer that strengthens the cell walls of a plant. It is indigestible to animals.


Macro minerals

Minerals required in large amounts for livestock. They include Calcium (Ca), Phosphorus (P), Potassium (K), Magnesium (Mg), and Sulphur (S).


Micro minerals

Minerals required in small amounts for livestock. They include Manganese (Mn), Iron (Fe), Copper (Cu), Zinc (Zn), and Molybdenum (Mo).


Net Energy (NE)

The energy used by an animal for maintenance and production. It is the energy that remains once fecal energy, energy lost in urine, heat loss, and combustible gases have all been subtracted from the gross energy. NE can be divided and analyzed further as NE for growth, lactation, and maintenance.


Net Energy for Gain/Growth (NEG)

The energy value that can be derived from a feed used for growth or weight gain above maintenance.



Net Energy for Lactation (NEL)

The energy value that can be derived from feed given to a milking cow. In a lactating dairy cow, NEL is the only energy estimate needed for ration balancing.


Net Energy for Maintenance (NEM)

The energy value that can be derived from feed that will keep an animal at a stable weight.



Neutral Detergent Fiber

A measure of the cellulose, hemicellulose, and lignin contents of a forage by boiling a feed in a neutral detergent solution. NDF levels are used to predict feed intake, where high levels of NDF are related to decreased intake. High levels of NDF can also limit forage value, and therefore low levels of NDF are typically desired. NDF is often reported as aNDF, including sodium and α-amylase.


Non-Protein Nitrogen (NPN)

Nitrogen that it not derived from a protein but is still usable by rumen microbes in the creation of microbial protein.



Protected amino acids

Amino acids that by-pass fermentation in the rumen.




Naturally occurring compounds, they are complex combinations of amino acids.


Relative Feed Quality (RFQ)

An accurate predictor of forage value, RFQ is a factor that combines predicted intake (NDF) with digestibility (ADF).


Roughage DMI (RDMI)

The predicted maximum forage intake.



Rumen Degradable Intake Protein (DIP)

Of the ingested proteins from the diet, DIP are those that are digested in the rumen to make microbial proteins. DIP is most affected by rates of passage.



Rumen Microbe

A microorganism in the rumen causing fermentation.



Rumen Undegradable Intake Protein (UIP)

A protein that escapes digestion in the rumen due to its slow rate of degradability. UIP are not used by rumen microbes and will either become absorbed in the small intestine or passed in the manure. UIP are also called escape proteins or bypass proteins.


Soluble Protein (SP)

Often expressed as a percent of CP, it is the protein that can be soluble in the rumen and is therefore rapidly degraded by rumen microbes.



A polysaccharide found mainly in the grain or seed of plants (non cell wall materials). Starch is a good source of energy.


Total Digestible Nutrients (TDN)

The energy value of feed.





Total DMI (TDMI)

The predicted maximum intake and is the main constraint in formulating a ration. TDMI varies with animal weight, requirements above maintenance (i.e. production, growth, gestation) and age. TDMI is regulated by both physiological and physical factors. Physiological factors include negative feedback of end products of digestion and metabolism. Physical factors include fiber content, capacity of the digestive tract, and rates of fermentation and passage.


Total Mixed Rations (TMR)

All feeds (forages and grain/supplement) are mixed together and fed free choice. Forages are fed as silage. Typical of free-stall and loose housing barns.


Volatile Fatty Acids (VFAs)

A main energy source for ruminants, VFAs are produced through ruminal fermentation. 3 major VFAs are acetate, proprionate, and butyrate.






Comparative Feed Values for Ruminants, OMAFRA

Definitions of Feed Manufacturing and Livestock Nutrition Terms, OMAFRA

Sheep Feeding Programs: Forage and Feed Analysis, OMAFRA

Understanding Feed Analysis Terminology, Agrifood Laboratories