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Commodities: Field Crops: Forages

Common Terms Used in Animal Feeding and Nutrition

Glossary: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

I

International unit (IU): A standard unit of potency of a biological agent (e.g., vitamin, hormone, antibiotic, antitoxin); also called a USP unit in the U.S.

In Vitro: In vitro (Latin for within the glass) generally refers to the technique of performing a given biological procedure in a controlled environment outside of a living organism. For example, it is a process that is carried out in a "test tube". In feed testing, in vitro refers to a feed sample that is digested in test tubes or tested outside the animal.

In vitro Digestibility or In vitro Dry Matter Digestibility (IVDMD): Digestibility of a feed determined by incubation of a ground feed sample with rumen fluid in a beaker or test tube for 24 to 48 hours, followed either by addition of acid and pepsin and further incubation for 24 hours or by boiling in neutral detergent fiber solution.

In situ Digestibility: Digestibility determined by incubation of a ground forage sample in a porous nylon bag placed within rumen via a fistula or port in the animal’s side (in situ) for a fixed time period.