Feed conversion ratio
In animal husbandry
Animal husbandry
Animal husbandry is the agricultural practice of breeding and raising livestock.- History :Animal husbandry has been practiced for thousands of years, since the first domestication of animals....

, feed conversion ratio (FCR), feed conversion rate, or feed conversion efficiency (FCE), is a measure of an animal
Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and...

's efficiency in converting feed
Feed may refer to:In animal foodstuffs:* Compound feed, feedstuffs that are blended from various raw materials and additives* Fodder , any foodstuff that is used specifically to feed domesticated livestockIn computing:...

Mass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:...

 into increased body mass.

Specifically FCR is the mass of the food eaten divided by the body mass gain, all over a specified period of time. FCR is dimensionless, i.e. there are no measurement unit
Units of measurement
A unit of measurement is a definite magnitude of a physical quantity, defined and adopted by convention and/or by law, that is used as a standard for measurement of the same physical quantity. Any other value of the physical quantity can be expressed as a simple multiple of the unit of...

s associated with FCR.

Animals that have a low FCR are considered efficient users of feed. Sheep and cattle
Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...

 need more than 8 kg of feed to put on 1 kg of live weight. The U.S. pork industry claims to have an FCR of 3.4-3.6 . Farm raised Atlantic salmon
Atlantic salmon
The Atlantic salmon is a species of fish in the family Salmonidae, which is found in the northern Atlantic Ocean and in rivers that flow into the north Atlantic and the north Pacific....

 apparently have a very good FCR, about 1.2.

Tilapia , is the common name for nearly a hundred species of cichlid fish from the tilapiine cichlid tribe. Tilapia inhabit a variety of fresh water habitats, including shallow streams, ponds, rivers and lakes. Historically, they have been of major importance in artisan fishing in Africa and the...

, typically, 1.6 to 1.8.
Poultry are domesticated birds kept by humans for the purpose of producing eggs, meat, and/or feathers. These most typically are members of the superorder Galloanserae , especially the order Galliformes and the family Anatidae , commonly known as "waterfowl"...

 has a feed conversion ratio of 2 to 1.
Ruminants can convert 7 kg of grain to one kilogram of meat.

Nonetheless this value is an underestimation of the FCR, for it does not take in account that normally the feed is in kg of “dry” weight and the live weight is in kg of “wet” weight. When both factors are transformed to either dry or wet weight the FCR increases 4 to 5-fold, depending on the feeding practice and species; mammal body weight is typically mostly water . Presently, technological advances in feed research are enabling salmon farmers to lower the “true” FCR to less than 4 (i.e. by substituting fish meal
Fish meal
Fish meal, or fishmeal, is a commercial product made from both whole fish and the bones and offal from processed fish. It is a brown powder or cake obtained by rendering pressing the cooked whole fish or fish trimmings to remove most of the fish oil and water, and then ground...

 and fish oil
Fish oil
Fish oil is oil derived from the tissues of oily fish. Fish oils contain the omega-3 fatty acids eicosapentaenoic acid , and docosahexaenoic acid , precursors of certain eicosanoids that are known to reduce inflammation throughout the body, and are thought to have many health benefits.Fish do not...

 with plant products such as soy and derivatives) which in consequence lowers the Salmon’s average trophic level
Trophic level
The trophic level of an organism is the position it occupies in a food chain. The word trophic derives from the Greek τροφή referring to food or feeding. A food chain represents a succession of organisms that eat another organism and are, in turn, eaten themselves. The number of steps an organism...


It is important to understand that the above discussion of dry weight vs. wet weight for FCRs in Salmon also applies to other animals, such as poultry, cattle, and beef. Those FCR's are also a conversion of dry feed to wet animal weight, so really the FCRs are still to the same proportions.
  • Be aware that some people define feed conversion efficiency as kg milk solids / kg Dry matter. Using this definition and equation a high feed conversion efficiency is desirable.

See also

  • Efficiency of conversion
    Efficiency of conversion
    The efficiency of conversion of ingested food to unit of body substance is an index measure of food fuel efficiency in animals. The ECI is a rough scale of how much of the food ingested is converted into growth in the animal's mass...

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.