{{Short description|Ratio of animal feed to desired product}} In [[animal husbandry]], '''feed conversion ratio''' ('''FCR''') or '''feed conversion rate''' is a [[ratio]] or [[rate (mathematics)|rate]] measuring of the [[efficiency]] with which the bodies of [[livestock]] convert [[animal feed]] into the desired output. For [[dairy cattle|dairy cows]], for example, the output is [[milk]], whereas in animals raised for [[meat]] (such as [[beef]] cows,<ref name=ShikeBeef>Dan Shike, University of Illinois [http://www.beefusa.org/CMDocs/BeefUSA/Resources/cc2012-Beef-Feed-Efficiency--Dan-Shike.pdf Beef Cattle Feed Efficiency]</ref> pigs, chickens, and fish) the output is the [[flesh]], that is, the body mass gained by the animal, represented either in the final mass of the animal or the mass of the [[animal slaughter|dressed]] output. FCR is the mass of the input divided by the output (thus mass of feed per mass of milk or meat). In some sectors, '''feed efficiency''', which is the output divided by the input (i.e. the [[Multiplicative inverse|inverse]] of FCR), is used. These concepts are also closely related to [[efficiency of conversion]] of ingested foods (ECI).
==Background== Feed conversion ratio (FCR) is the ratio of inputs to outputs; it is the inverse of "feed efficiency" which is the ratio of outputs to inputs.<ref name=Cottle>DJ Cottle and WS Pitchford. Production Efficiency. Chapter 18 in Beef Cattle Production and Trade, Ed Lewis Kahn. Csiro Publishing, 2014 {{ISBN|978-0-643-10989-6}} [https://books.google.com/books?id=suFZAwAAQBAJ&pg=PA439 Pp 439-440]</ref> FCR is widely used in hog and poultry production, while FE is used more commonly with cattle.<ref name=Cottle/> Being a ratio the FCR is [[dimensionless]], that is, it is not affected by the [[units of measurement]] used to determine the FCR.<ref>Stickney, Robert R. (2009) [https://books.google.com/books?id=UaT8gZaOA04C&q=%22Feed+conversion+ratio%22+dimensionless&pg=PA248 ''Aquaculture: An Introductory Text''], page 248, CABI, {{ISBN|978-1-84593-589-4}}.</ref>
FCR a function of the animal's genetics<ref>Arthur P.F. et al. 2014 [https://web.archive.org/web/20151109210517/https://www.asas.org/docs/default-source/wcgalp-proceedings-oral/110_paper_10178_manuscript_1215_0.pdf?sfvrsn=2 Lessons Learnt from 25 Years of Feed Efficiency Research in Australia]. Proceedings, 10th World Congress of Genetics Applied to Livestock Production. Abstract here [https://asas.confex.com/asas/WCGALP14/webprogram/Paper10178.html]</ref> and age,<ref name=Varley/> the quality and ingredients of the feed,<ref name=Varley/> and the conditions in which the animal is kept,<ref name=ShikeBeef/><ref>National Research Council (Subcommittee on Environmental Stress). 1981. Effect of environment on nutrient requirements of domestic animals. National Academy Press, Washington. 168 pp.</ref> and storage and use of the feed by the farmworkers.<ref>Dennis DiPietre for Pig 333. April 21, 2014 [https://web.archive.org/web/20140503042415/http://www.pig333.com/swin_markets_commentaries/feed-conversion-ratio-critically-important-but-often-misused_8570/ Feed Conversion Ratio: critically important but often misused]</ref>
As a rule of thumb, the daily FCR is low for young animals (when relative growth is large) and increases for older animals (when relative growth tends to level out). However FCR is a poor basis to use for selecting animals to improve genetics, as that results in larger animals that cost more to feed; instead [[residual feed intake]] (RFI) is used which is independent of size.<ref name=Shike2013/> RFI uses for output the difference between actual intake and predicted intake based on an animal's body weight, weight gain, and composition.<ref name=Shike2013/><ref>Travis D. Maddock, Darren D. Henry, and G. Cliff Lamb. Animal Sciences Department, UF/IFAS Extension. [https://web.archive.org/web/20160310005835/http://edis.ifas.ufl.edu/an217 AN217: The Economic Impact of Feed Efficiency in Beef Cattle] Original publication date May 2009. Revised October 2015.</ref>
The outputs portion may be calculated based on weight gained, on the whole animal at sale, or on the dressed product; with milk it may be normalized for fat and protein content.<ref name=Fry/>
As for the inputs portion, although FCR is commonly calculated using feed dry mass, it is sometimes calculated on an as-fed wet mass basis, (or in the case of grains and oilseeds, sometimes on a wet mass basis at standard moisture content), with feed moisture resulting in higher ratios.<ref name=Ishler/>
==Conversion ratios for livestock== Animals that have a low FCR are considered efficient users of feed. However, comparisons of FCR among different species may be of little significance unless the feeds involved are of similar quality and suitability.
===Beef cattle=== {{as of|2013}} in the US, an FCR calculated on live weight gain of 4.5–7.5 was in the normal range with an FCR above 6 being typical.<ref name=Shike2013>Dan W. Shike, Ph.D., University of Illinois at Urbana-Champaign Driftless Region Beef Conference 2013 [https://web.archive.org/web/20160616072736/http://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1027&context=driftlessconference Beef Cattle Feed Efficiency]</ref> Divided by an average carcass yield of 62.2%, the typical carcass weight FCR is above 10. {{as of|2013}}, FCRs had not changed much compared to other fields in the prior 30 years, especially compared to poultry which had improved feed efficiency by about 250% over the last 50 years.<ref name=Shike2013/>
===Dairy cattle=== The dairy industry traditionally didn't use FCR but in response to increasing concentration in the dairy industry and other livestock operations, the [[United States Environmental Protection Agency|EPA]] [[Concentrated Animal Feeding Operation#EPA final rule (2003)|updated its regulations in 2003]] controlling manure and other waste releases produced by livestock operators.<ref>Cornell University, University of Wisconsin-Madison, USDA-Agricultural Research Service, Dairy Forage Research Center April 30, 2004 [https://web.archive.org/web/20140117181322/http://www.manuremanagement.cornell.edu/Pages/General_Docs/Reports/Whole_Farm_NM_on_Dairy_Farms_to_Improve_Profitability_and_Reduce_Env_Impacts.pdf Whole-Farm Nutrient Management on Dairy Farms to Improve Profitability and Reduce Environmental Impacts]</ref>{{rp|11-11}} In response, the [[United States Department of Agriculture|USDA]] began issuing guidance to dairy farmers about how to control inputs to better minimize manure output and to minimize harmful contents, as well as optimizing milk output.<ref name=Hutiens/><ref>USDA Natural Resources Conservation Service [https://web.archive.org/web/20121024103048/http://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb1046856.pdf Conservation Practice Standard: Feed Management: (Animal Units (AUs) Affected): Code 592]. September 2011</ref>
In the US, the price of milk is based on the protein and fat content, so the FCR is often calculated to take that into account.<ref name=Hall>Tony Hall for Eastern Dairy Business September 2011 [https://web.archive.org/web/20160616035304/http://lallemandanimalnutrition.com/wp-content/uploads/2011/10/Hal_Dairybusiness_09111.pdf Define And Improve Your Herd's Feed Conversion Ratio]</ref> Using an FCR calculated just on the weight of protein and fat, {{as of|2011|lc=y}} an FCR of 13 was poor, and an FCR of 8 was very good.<ref name=Hall/>
Another method for dealing with pricing based on protein and fat, is using energy-corrected milk (ECM), which adds a factor to normalize assuming certain amounts of fat and protein in a final milk product; that formula is (0.327 x milk mass) + (12.95 x fat mass) + (7.2 x protein mass).<ref name=Ishler>Virginia Ishler for Progressive Dairyman. June 30, 2014 [https://web.archive.org/web/20160616040107/http://www.progressivedairy.com/topics/feed-nutrition/calculating-feed-efficiency Calculating feed efficiency]</ref>
In the dairy industry, feed efficiency (ECM/intake) is often used instead of FCR (intake/ECM); an FE less than 1.3 is considered problematic.<ref name=Hutiens>Michael F. Hutjens August 21, 2012 [https://web.archive.org/web/20160616043236/http://articles.extension.org/pages/11317/feed-efficiency-and-its-impact-on-feed-intake Feed Efficiency and Its Impact on Feed Intake]</ref><ref name=Ishler/>
FE based simply on the weight of milk is also used; an FE between 1.30 and 1.70 is normal.<ref name=Fry>Robert C. Fry, Atlantic Dairy Management Services. [http://dairy.ifas.ufl.edu/rns/2011/2fry.pdf Measuring Feed Efficiency Why & How on the Back of a Napkin]</ref>
===Pigs=== Pigs have been kept to produce meat for 5,000 to 9,000 years.<ref name="Jukes_1992">{{cite journal | vauthors = Jukes TH| title = Today's non-Orwellian animal farm | journal = Nature | volume = 355 | issue = 6361 | pages = 582| date = February 1992 | doi =10.1038/355582a0 |pmid = 1538742 | pmc= | s2cid = 4308400 | doi-access = free }}</ref> {{as of|2011}}, pigs used commercially in the UK and Europe had an FCR, calculated using weight gain, of about 1 as piglets and ending about 3 at time of slaughter.<ref name=Varley>Mike Varley for Pig Progress. [https://web.archive.org/web/20150917051750/http://www.pigprogress.net/Breeding/Sow-Feeding/2009/4/Taking-control-of-feed-conversion-ratio-PP005927W/ Taking control of feed conversion ratio] Apr 1, 2009, Last update:Jan 26, 2011</ref> {{as of|2012}}, in Australia and using dressed weight for the output, an FCR calculated using weight of dressed meat of 4.5 was fair, 4.0 was considered "good", and 3.8, "very good".<ref>Department of Agriculture and Fisheries, Queensland Government. Managing a piggery >> Production and performance >> [https://web.archive.org/web/20160616102808/https://www.daf.qld.gov.au/animal-industries/pigs/managing-a-piggery/production-and-performance/performance-standards Performance standards] Last updated 28 September 2012</ref>
The FCR of pigs is greatest up to the period, when pigs weigh 220 pounds. During this period, their FCR is 3.5.<ref name="Jukes_1992"/> Their FCR begins increasing gradually after this period. For instance, in the US {{as of|2012|lc=y}}, commercial pigs had FCR calculated using weight gain, of 3.46 for while they weighed between 240 and 250 pounds, 3.65 between 250 and 260 pounds, 3.87 between 260 and 270 lbs, and 4.09 between 280 and 270 lbs.<ref>David R. Stender, Iowa State University Extension. [https://web.archive.org/web/20150909053400/http://www.swinefeedefficiency.com/factsheets/IPIC25h%20SFE%20Influence%20of%20Market%20Weight.pdf IPIC 25h. Swine Feed Efficiency: Influence of Market Weight] 2012</ref>
Because FCR calculated on the basis of weight gained gets worse after pigs mature, as it takes more and more feed to drive growth, countries that have a culture of slaughtering pigs at very high weights, like Japan and Korea, have poor FCRs.<ref name=Varley/>
===Sheep=== Some data for sheep illustrate variations in FCR. An FCR (kg feed dry matter intake per kg live mass gain) for lambs is often in the range of about 4 to 5 on high-concentrate rations,<ref>Knott, S. A., B. J. Leury, L. J. Cummins, F. D. Brien and F. R. Dunshea. 2003. Relationship between body composition, net feed intake and gross feed conversion efficiency in composite sire line sheep. In: Souffrant, W. B. and C. C. Metges (eds.). Progress in research on energy and protein metabolism. EAAP publ. no. 109. Wageningen</ref><ref>Brand, T. S., S. W. P. Cloete and F. Franck. 1991. Wheat-straw as roughage component in finishing diets of growing lambs. S. Afr. J. Anim. Sci 21: 184-188.</ref><ref name=NRC2007>National Research Council. 2007. Nutrient requirements of small ruminants. National Academies Press. 362 pp.</ref> 5 to 6 on some forages of good quality,<ref>Fahmy, M. H., J. M. Boucher, L. M. Pose, R. Grégoire, G. Butler and J. E. Comeau. 1992. Feed efficiency, carcass characteristics, and sensory quality of lambs, with or without prolific ancestry, fed diets with different protein supplements. J. Anim. Sci. 70: 1365-1374</ref> and more than 6 on feeds of lesser quality.<ref>Malik, R. C., M. A. Razzaque, S. Abbas, N. Al-Khozam and S. Sahni. 1996. Feedlot growth and efficiency of three-way cross lambs as affected by genotype, age and diet. Proc. Aust. Soc. Anim. Prod. 21: 251-254.</ref> On a diet of straw, which has a low metabolizable energy concentration, FCR of lambs may be as high as 40.<ref>Cronjé. P. B. and E. Weites. 1990. Live mass, carcass and wool growth responses to supplementation of a roughage diet with sources of protein and energy in South African Mutton Merino lambs. S. Afr. J. Anim. Sci. 20: 141-168</ref> Other things being equal, FCR tends to be higher for older lambs (e.g. 8 months) than younger lambs (e.g. 4 months).<ref name=NRC2007/>
===Poultry=== {{as of|2011}}, in the US, broiler chickens has an FCR of 1.6 based on body weight gain, and mature in 39 days.<ref name=Best2011/> At around the same time, the FCR based on weight gain for broilers in Brazil was 1.8.<ref name=Best2011/> The global average in 2013 is around 2.0 for weight gain (live weight) and 2.8 for slaughtered meat (carcass weight).<ref name=fao-chi-po>{{cite book |last1=MacLeod |first1=M. |last2=Gerber |first2=P. |last3=Mottet |first3=A. |last4=Tempio |first4=G. |last5=Falcucci |first5=A. |last6=Opio |first6=C. |last7=Vellinga |first7=T. |last8=Henderson |first8=B. |last9=Steinfeld |first9=H. |title=Greenhouse gas emissions from pig and chicken supply chains – a global life cycle assessment |date=2013 |publisher=Food and Agriculture Organization of the United Nations |isbn=978-92-5-107944-7 |url=http://www.fao.org/3/i3460e/i3460e.pdf}}</ref>
For hens used in egg production in the US, {{as of|2011|lc=y}} the FCR was about 2, with each hen laying about 330 eggs per year.<ref name=Best2011>Peter Best for WATTagnet.com November 24, 2011 [https://web.archive.org/web/20160616092918/http://www.wattagnet.com/articles/10427-poultry-performance-improves-over-past-decades Poultry performance improves over past decades]</ref> When slaughtered, the world average layer flock as of 2013 yields a carcass FCR of 4.2, still much better than the average backyard chicken flock (FCR 9.2 for eggs, 14.6 for carcass).<ref name=fao-chi-po/>
From the early 1960s to 2011, in the US, broiler growth rates doubled and their FCRs halved, mostly due to improvements in genetics and rapid dissemination of the improved chickens.<ref name=Best2011/> The improvement in genetics for growing meat created challenges for farmers who breed the chickens that are raised by the broiler industry, as the genetics that cause fast growth decreased reproductive abilities.<ref>Mississippi State University Extension Service [https://web.archive.org/web/20160616101934/http://extension.msstate.edu/sites/default/files/publications/publications/p2783.pdf Broiler Breeder Management Is No Easy Task], 2013</ref>
===Carnivorous fish=== In [[aquaculture]], the fish feed for carnivorous fish commonly includes fish-derived products in the form of [[fishmeal]] and [[fish oil]]. There are therefore two ratios to be reported:<ref>{{Cite web |url=http://www.iffo.net/cn/system/files/100.pdf |title=FIFO explanation document |access-date=2016-06-04 |archive-date=2016-10-10 |archive-url=https://web.archive.org/web/20161010101003/http://www.iffo.net/cn/system/files/100.pdf |url-status=dead }}</ref><ref>{{cite web |url=http://www.feap.info/default.asp?SHORTCUT=603 |title=FIFO explained |access-date=2016-06-04 |archive-url=https://web.archive.org/web/20160701195846/http://www.feap.info/default.asp?SHORTCUT=603 |archive-date=2016-07-01 |url-status=dead }}</ref>
* The regular feed conversion ratio, i.e. output fish mass divided by total feed mass. * The conversion ratio only taking into account the fish-based component of fish feed, called the FIFO ratio (or Fish In – Fish Out ratio). FIFO is fish in (the mass of harvested fish used to feed farmed fish) divided by fish out (mass of the resulting farmed fish).
FIFO is a way of expressing the contribution from harvested wild fish used in aquafeed compared with the amount of edible farmed fish, as a ratio. The fish used in fishmeal and fish oil production are not used for human consumption, but with their use as fishmeal and fish oil in aquafeed they contribute to global food production.
Fishmeal and fish oil inclusion rates in aquafeeds have shown a continual decline over time as aquaculture grows and more feed is produced, but with a finite annual supply of fishmeal and fish oil. Calculations have shown that the overall fed aquaculture FIFO declined from 0.63 in 2000 to 0.33 in 2010, and 0.22 in 2015. In 2015, therefore, approximately 4.55 kg of farmed fish was produced for every 1 kg of wild fish harvested and used in feed. (For Salmon & Trout, the FIFO ratios for 2000, 2010, and 2015 are: 2.57, 1.38, 0.82.)<ref>{{cite web |url=http://www.iffo.net/fish-fish-out-fifo-ratios-conversion-wild-feed |title=Fish in: Fish Out (FIFO) ratios for the conversion of wild feed to farmed fish, including salmon |work=IFFO |date=2010-04-16 |archive-url=https://web.archive.org/web/20201031044911/https://www.iffo.com/fish-fish-out-fifo-ratios-conversion-wild-feed |archive-date=2020-10-31 |url-status=dead}}</ref>
{{as of|2015}} farm-raised [[Atlantic salmon]] had a commodified feed supply with four main suppliers, and an FCR of around 1.<ref>FAO [https://www.fao.org/fishery/en/culturedspecies/salmo_salar/en Cultured Aquatic Species Information Programme: Salmo salar (Linnaeus, 1758)] 2004</ref> [[Tilapia]] is about 1.5,<ref>Dennis P. DeLong, Thomas M. Losordo and James E. Rakocy Southern Regional Aquaculture Center [https://web.archive.org/web/20151106233121/http://www2.ca.uky.edu/wkrec/TilapiaTankCulture.pdf SRAC Publication No. 282: Tank Culture of Tilapia] June 2009</ref> and {{as of|2013|lc=y}} farmed [[catfish]] had an FCR of about 1.<ref name=Shike2013/>
It is possible for fish to have an FCR below 1 despite obvious energy losses in feed-to-meat conversion. Fish feed tends to be dry food with higher energy density than water-rich fish flesh.<ref>{{cite web |author=USAID Harvest |title=Technical Bulletin #07: Feed Conversion Ratio (FCR): How to calculate it and how it is used |url=https://pdf.usaid.gov/pdf_docs/PA00K8MQ.pdf |archive-url=https://web.archive.org/web/20170131140103/http://pdf.usaid.gov/pdf_docs/PA00K8MQ.pdf |url-status=dead |archive-date=January 31, 2017 |access-date=22 March 2024}}</ref>
===Herbivorous and omnivorous fish=== For herbivorous and omnivorous fish like [[Chinese carp]] and [[tilapia]], the plant-based feed yields much lower FCR compared to carnivorous kept on a partially fish-based diet, despite a decrease in overall resource use. The edible (fillet) FCR of tilapia is around 4.6 and the FCR of Chinese carp is around 4.9.<ref name=GFS/>
=== Rabbits === In India, rabbits raised for meat had an FCR of 2.5 to 3.0 on high grain diet and 3.5 to 4.0 on natural forage diet, without animal-feed grain.<ref>{{cite web |url=https://agritech.tnau.ac.in/animal_husbandry/animhus_rabbitbreed.html |title=Animal Husbandry: Rabbit |work=[[Tamil Nadu Agricultural University]] Agritech Portal |access-date=2026-05-22}}</ref>
=== Global averages by species and production systems === In a global study, [[Food and Agriculture Organization|FAO]] estimated various feed conversion ratios, taking into account the diversity of feed material consumed by livestock.<ref name=":0">{{Cite book |author1=Mottet, A. |author2=de Haan, C. |author3=Falcucci, A. |author4=Tempio, G. |author5=Opio, C. |author6=Gerber, P. |url=https://www.fao.org/documents/card/en/c/cc3134en |title=More fuel for the food/feed debate |publisher=FAO |year=2022 |location=Rome}}</ref><ref name=":1">{{Cite journal |last1=Mottet |first1=Anne |last2=de Haan |first2=Cees |last3=Falcucci |first3=Alessandra |last4=Tempio |first4=Giuseppe |last5=Opio |first5=Carolyn |last6=Gerber |first6=Pierre |date=2017-09-01 |title=Livestock: On our plates or eating at our table? A new analysis of the feed/food debate |url=https://www.sciencedirect.com/science/article/pii/S2211912416300013 |journal=Global Food Security |series=Food Security Governance in Latin America |volume=14 |pages=1–8 |doi=10.1016/j.gfs.2017.01.001 |bibcode=2017GlFS...14....1M |issn=2211-9124|url-access=subscription }}</ref> At global level, ruminants require 133 kg of dry matter per kg of protein while [[monogastric]]s require 30 kg.<ref name=":0" /><ref name=":1" /> However, when considering human edible feed only, ruminants require 5.9 kg of feed to produce 1 kg of animal protein, while monogastrics require 15.8 kg.<ref name=":0" /><ref name=":1" /> When looking at meat only, ruminants consume an average of 2.8 kg of human edible feed per kg of meat produced, while monogastrics need 3.2 kg.<ref name=":0" /><ref name=":1" /> Finally, when accounting for the protein content of the feed, ruminant need an average of 0.6 kg of edible plant protein to produce 1 kg of animal protein while monogastric need 2 kg.<ref name=":0" /><ref name=":1" /> This means that ruminants make a positive net contribution to the supply of edible protein for humans at global level.<ref name=":0" /><ref name=":1" />
== Feed conversion ratios of meat alternatives ==
Many alternatives to conventional animal meat sources have been proposed for higher efficiency, including insects, [[meat analogue]]s, and [[cultured meat]]s.<ref name=GFS/>
===Insects=== Although there are few studies of the feed conversion ratios of [[Insects as food|edible insects]], the [[house cricket]] (''Acheta domesticus'') has been shown to have an FCR of 0.9 - 1.1 depending on diet composition.<ref>{{cite journal |last=van Huis |first=Arnold |author-link=Arnold van Huis |title=Potential of Insects as Food and Feed in Assuring Food Security |journal=[[Annual Review of Entomology]] |date=7 January 2013 |volume=58 |issue=1 |pages=563–583 |doi=10.1146/annurev-ento-120811-153704 |doi-access=free}}</ref> A more recent work gives an FCR of 1.9–2.4. Reasons contributing to such a low FCR include the whole body being used for food, the lack of internal temperature control (insects are [[poikilotherm|poikilothermic]]), high fecundity and rate of maturation.<ref name=GFS>{{cite journal |last1=Alexander |first1=Peter |last2=Brown |first2=Calum |last3=Arneth |first3=Almut |last4=Dias |first4=Clare |last5=Finnigan |first5=John |last6=Moran |first6=Dominic |last7=Rounsevell |first7=Mark D.A. |title=Could consumption of insects, cultured meat or imitation meat reduce global agricultural land use? |journal=Global Food Security |date=December 2017 |volume=15 |pages=22–32 |doi=10.1016/j.gfs.2017.04.001|doi-access=free |bibcode=2017GlFS...15...22A |hdl=20.500.11820/17f627e0-ff81-4492-87d8-97bd6f454840 |hdl-access=free }}</ref>
===Meat analogue=== If one treats [[tofu]] as a meat, the FCR reaches as low as 0.29. The FCRs for less watery forms of meat analogues are unknown.<ref name=GFS/>
===Cultured meat=== Although [[cultured meat]] has a potentially much lower land footprint required, its FCR is closer to poultry at around 4 (2-8). It has a high need for energy inputs.<ref name=GFS/>
==See also== * [[Entomophagy]] * [[Food vs. feed]] * [[Life-cycle assessment]]
==References== {{Reflist}}
{{Meat}} {{modelling ecosystems}}
{{DEFAULTSORT:Feed Conversion Ratio}} [[Category:Livestock]] [[Category:Poultry farming]] [[Category:Animal breeding]]