Feeds are various substances of plant, animal, mineral and synthetic origin that contain one or more nutrients. Nutrients are divided into organic (e.g. proteins, amino acids, lipids, carbohydrates, vitamins, etc.) and inorganic (e.g. calcium, phosphorus, sodium, chlorine, potassium, magnesium, sulfur, iron, etc.) .).
The various fodder, as harvested or generally produced, constitute the so-called simple feed (alfalfa hay, corn seeds, meat meal, etc.). Simple forages are classified according to their cellulose and water content into woody, roughage, succulent roughage and concentrates.
Homogeneous mixing of simple feed leads to the preparation of compound feed. Compound feeds can be complete, when given to animals they are able to cover all the nutritional needs of the animal body by themselves, or supplementary, when they do not by themselves cover all the nutritional needs of the animal organism and must be administered in combination with other animal feeds that constitute the so-called basic feedstuffs, because as a rule they must make up the largest proportion of the feed.
Indicatively, the chemical and microbiological analyzes carried out in the laboratory are the following: