Glossary search results: 13

FALSE NEGATIVE

An animal that tests as negative but who is actually positive. The percent of false negative for a test can be calculated as 100 – SENSITIVITY.


FALSE POSITIVE

An animal that tests as positive but who is actually negative. The percent of false positive for a test can be calculated as 100 – SPECIFICITY.


FAT

1. Ester of glycerol and fatty acids. 2. Organic compound containing carbon, hydrogen and oxygen, but as opposed to the carbohydrates, fats have a ratio of hydrogen to oxygen well above 2:1. Fats, as opposed to oils, are solids at room temperature and usually are of animal origin.


FATTY ACID

A chain of carbon terminated by an acid (carboxyl) group (COOH). Fatty acids with less than 4 carbon units are volatile. Fatty acids with 5 to 20 carbon units are usually found as part of fats and oils.


FERMENTATION (in the rumen)

The transformation of carbohydrates in absence of oxygen by rumen micro flora that produces volatile fatty acids such as acetic acid, propionic acid and butyric acid, and gases such as carbon dioxide (CO2) and methane (CH4).


FETUS

The unborn young.


FIBER (dietary)

Nutrient of low energy density present in large quantities in forages. Fiber is composed of structural carbohydrates (cellulose and hemicellulose) and phenolic compounds. Fiber is important for dairy cows because they stimulate rumination and promote a healthy rumen environment for bacterial growth. However, in large amounts in the diet, fiber may fill the rumen, limit intake of energy and constrain milk production.


FIBROUS CARBOHYDRATE

Hemicellulose and cellulose that can be quantify by the neutral detergent fiber procedure.


FODDER

Coarse feeds, such as straw, corn or sorghum stalks.


FORAGE

Feed that stimulate rumination due to their long particle size and their high content in fiber. Generally, forages are composed of the leaves and stems (stalk of plants. The bacterial population of the rumen allows the ruminant to digest forages.


FORAGE TO CONCENTRATE RATIO

Usually expressed as two percentages. The percentage of ration dry matter that is made up of forage and the percentage of ration dry matter that is composed of concentrates. The two total 100. For example a 50:50 forage to concentrate ratio means that a cow eating 20 kg of dry matter of that ration would eat 10 kg of concentrate dry matter and 10 kg of forage dry matter.


FRUCTANS

Is a polymer of fructose molecules generally, but not always, found as "carbohydrate storage in cool season grasses (C3 plants). Tall fescue and perennial ryegrass tend to have the highest levels of fructans when compared to other grasses under the same conditions. Fructan is stored in vacuoles inside cells throughout the plant where it is readily available as needed. In some species of grass the lower part of the stem is a carbohydrate storage organ.


FRUCTOSE (C6H12O6)

A sweet sugar occurring in many fruits and honey.