- Feed conversion ratio
In
animal husbandry , feed conversion ratio (FCR), feed conversion rate, or feed conversion efficiency (FCE), is a measure of ananimal 's efficiency in convertingfeed mass into increasedbody 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 units associated with FCR. Animals that have a low FCR are considered efficient users of feed.Sheep andcattle 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 [ [http://www.pork.org/newsandinformation/quickfacts/porkstory2.aspx Pork Checkoff - Quick Facts - Pork Story ] ] . Farm raisedAtlantic salmon apparently have a very good FCR, about 1.2.Tilapia , typically, 1.6 to 1.8ftp://ftp.fao.org/docrep/fao/010/a0701e/a0701e.pdf] .Poultry has a feed conversion ratio of 2 to 4.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 more than often 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 to between 4 and 5, depending on the feeding practice. Presently, technological advances in feed research are enabling salmon farmers to lower the “true” FCR to 4 and under (i.e. by substituting
fish meal andfish oil with plant products such assoy and derivatives) which in consequence lowers the Salmon’s averagetrophic level fact|date=October 2008.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 proportionsfact|date=October 2008.
References
Reflist|1 [Brown, L., Hindmarsh, R., Mcgregor, R., 2001. Dynamic Agriculture Book Three (2nd ed.). McGraw-Hill Book Company, Sydney.]
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