Glossary of Nutrition and Feed Terms

We love to talk ingredients and nutrition. But sometimes the technical terms can be baffling to others. This helpful glossary will help!

Acid detergent fiber (ADF):

Essentially indigestible fiber. Includes cellulose, lignin, and ash. The higher the ADF, the lower the digestibility or available energy. Low ADF forages are usually preferred, because it means higher net energy. As the plant matures, ADF increases.

Amino acids:

The building blocks of proteins. Used extensively for milk and muscle protein synthesis. Used also for glucose synthesis in the liver.

Ammonia:

A colorless nitrogen compound produced as protein and nonprotein nitrogen degrades or breaks down in the rumen.

Ash:

The mineral matter present in feed. It is measured by burning the sample at 500° C until all organic matter is burned and removed.

Available protein:

Determined by subtracting unavailable protein from crude protein.

Buffer:

Chemical compound that resists changes in pH with the addition (or loss) of acid or base. Buffers, such as sodium bicarbonate, are supplemented to reduce the risk of rumen acidosis (low pH).

Cellulose:

The principle carbohydrate constituent of plant cell membranes. It is made available to ruminants through the action of cellulolytic bacteria in the rumen. Monogastrics use enzymes to digest cellulose.

Carbohydrates:

Includes the sugars, starch, cellulose, gums, and related substances. (Sometimes referred to as “energy”.)

Concentrate:

A broad classification of feedstuffs that are high in energy and low in crude fiber (less than 18 percent). Included are cereal grains, soybean meal, and by-products of the milling industry such as corn gluten and wheat bran. A concentrate may be low or rich in protein.

Crude fiber (CF):

That portion of feedstuffs composed of polysaccharides such as cellulose, hemicellulose, and lignin. These serve as structural and protective parts of plants (high in forages and low in grains). CF is no longer considered a viable measurement.

Crude fat:

A measure of the fat content as determined by ether extraction. This measure may also contain plant pigments, esters and aldehydes.

Crude protein (CP):

Total protein in a feed. To calculate the protein percentage, a feed is first chemically analyzed for nitrogen content. Since proteins average approximately 16 percent nitrogen, the percentage of nitrogen in the analysis is multiplied by 6.25 to give the percent CP.

Digestible dry matter (DDM):

Estimates the percentage of forage that is digestible.

Dry matter (DM):

That part of feed, which is not water. Percent DM = 100% - moisture %. (Most grains and forages contain 10-15% moisture.)

Dry matter intake (DMI):

Estimates the maximum amount of forage dry matter an animal will eat.

Fiber:

The cellulose portion of roughages (forages) that is low in TDN and hard to digest by monogastric animals.

Forage:

The vegetative portion of plants in a fresh, dried, or ensiled state which is fed to livestock. Grasses and legumes cut at the proper stage of maturity and stored to preserve quality.

Hay:

Dried forage (grasses, alfalfa, clovers) used for feeding farm animals.

Legume:

Clovers, alfalfa, and similar crops that can absorb nitrogen directly from the atmosphere through action of bacteria that live in their roots and use it as a nutrient for growth.

Lignin:

A compound which, with cellulose, forms the cell walls of plants. It is practically indigestible.

Lipid:

Also known as fats. They are rich sources of dietary energy.

Minerals:

Calcium (Ca), phosphorus (P) and other minerals are normally expressed as a percentage of each in the feed. Exact listings vary based by type of animal.

Net energy (NE):

Is the energy available to an animal in a feed after removing the energy lost as feces, urine, gas and heat produced during digestion and metabolism. NE is the most useful energy estimate for formulating rations.

Neutral detergent fiber (NDF):

This is the digestible form of fiber. Low NDF is usually desired. As maturity of the plant at harvest increases, cell wall content of the plant increases and NDF increases.

Nonfiber carbohydrates (NFC):

The highly digestible non-cell wall carbohydrate fraction of feeds consisting of starch, sugar, and pectin. Also called nonstructural carbohydrates (NSC).

Roughage:

Consists of pasture, silage, hay, or other dry fodder. It may be of high or low quality. Roughages are usually high in crude fiber (more than 18 percent) and relatively low in NFE (approximately 40 percent).