Residual feed intake (sometimes shortened in literature to RFI) is a

resource allocation In economics, resource allocation is the assignment of available resources to various uses. In the context of an entire economy, resources can be allocated by various means, such as markets, or planning. In project management, resource allocati ...

theory index used to calculate the feed efficiency of growing

cattle Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus '' Bos''. Adult females are referred to as cows and adult ...

. It was developed by Robert M. Koch in 1963 as an answer to the difficulties of using a feed conversion ratio to compare individual animals.Sainz, Roberto D.; & Paulino, Pedro V.(2004)
Residual Feed Intake
UC Davis: Sierra Foothill Research and Extension Center Effective use of RFI data can greatly improve

beef cattle Beef cattle are cattle raised for meat production (as distinguished from dairy cattle, used for milk production). The meat of mature or almost mature cattle is mostly known as beef. In beef production there are three main stages: cow-calf oper ...

farm profits. This approach is based on regression models developed for determining efficiency of feed use for weight gain during a standardized growth trial in growing beef cattle. It was inspired by Koch's observations of the differences in how a maintained body weight and an increasing body weight affect the feeding of cattle. His research suggested that feed intake could be broken into two parts: # The expected feed intake for the animal's level of production. # The residual portion between the amount of feed the animal is expected to eat, and what the animal actually eats. Through the use of these two items, animals that deviate from the expected feed intake, either by eating more than or less than what's expected of them, can be identified and managed as the farmer sees fit. Because feed intake is

heritable Heredity, also called inheritance or biological inheritance, is the passing on of traits from parents to their offspring; either through asexual reproduction or sexual reproduction, the offspring cells or organisms acquire the genetic inf ...

, knowing the RFI index of an animal is also useful when breeding. By selecting animals with the aim to reduce RFI, farmers can breed animals that eat less but continue at the same rate of production. There is no

phenotype In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological prop ...

link between RFI and the characteristics used to calculate expected feed intake, which allows for the comparison of animals who function at differing production numbers. This has led some authors to believe that RFI is representative of individual differences in the

metabolic Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cel ...

processes of the animals. For example, one study shows that the amount of feed a

Hereford Hereford () is a cathedral city, civil parish and the county town of Herefordshire, England. It lies on the River Wye, approximately east of the border with Wales, south-west of Worcester and north-west of Gloucester. With a populatio ...

bull requires to maintain a kilogram of body weight is closely related to genetic variation in its RFI. Similarly, in

laying hen Poultry farming is the form of animal husbandry which raises domesticated birds such as chickens, ducks, turkeys and geese to produce meat or eggs for food. Poultry – mostly chickens – are farmed in great numbers. More than 60 billion chicke ...

s, variation in RFI is directly linked to variations in maintenance energy expenditure.

References

{{reflist Agricultural economics Cattle