What you need to know about Residual Feed Intake (RFI)….
What is Residual Feed Intake or RFI?
Residual Feed Intake or RFI is defined as the difference between an animal’s
actual feed intake and its expected feed requirements for maintenance and growth. RFI is the variation in feed in-
take that remains after the requirements for maintenance and growth have been met. Efficient animals eat less than
expected and have a negative or low RFI, while less efficient animals eat more than expected and have a positive or
high RFI.
How is RFI measured?
To accurately measure RFI, you have to weigh and log an individual animal’s feed
consumption and compare that amount to the animal’s expected intake over a standardized test period. The
technology to do this accurately is available utilizing the GrowSafe feed system. The system has individual bunks
that sit on weigh bars that are configured for only one animal to eat at a time. Feed is available free choice and every
animal on test has an EID tag. When an animal’s head enters the bunk, it passes a sensor that records that individual
EID number and measures the amount of feed consumed by that individual. The sensors and weigh bars are tak-
ing second by second readings. This feed intake data is instantly transmitted wirelessly to a dedicated computer and
stored in its database. All this data and individual animal information and weights are sent to Dr. Monty Kerley at the
University of Missouri for analysis and to compute an RFI score.
How is RFI reported?
RFI is reported in numerical form plus or minus in pounds of feed. Each group is forced to
have an average of zero. The RFI results can range from a minus 3.5 to a plus 3.5. Using this range there can be a dif-
ference of 7 pounds of feed consumed per day to achieve a comparable gain.
How important is RFI data?
The economic relevance of RFI is significant. RFI is moderately heritable at .28-.44
comparable with other production traits. By selecting for feed efficiency various research documents an increase in
carrying capacity of 10% or more and increased feedlot profitability of 10-15%. Imagine reducing feed costs by over
10% or running 10% more cattle on the same resources. However, selecting for RFI must be done as part of a bal-
anced selection program as other traits such as disposition, calving ease, fertility, growth, milk and carcass also have
significant economic relevance. Each producer or rancher must analyze their individual situations to determine what
traits will be most beneficial to their bottom line.
How does Seedstock Plus factor in?
Seedstock Plus has been RFI testing bulls since 2010. We embraced the impor-
tance of this data for our use as breeders and also to enhance the selection available to our customers. In the summer
of 2013 we purchased and installed our own GrowSafe systems in MO and AZ. In the fall of 2015, we expanded the
MO system. This will enable us to RFI test over 550 bulls and 200 females each year. Accelerating the amount of
data generated to incorporate with all other data Seedstock Plus has been collecting such as DNA and ultrasound.
Reading the RFI test results.
Group: Denotes which group the bull was tested in. The RFI score of bulls from one group should not be compared to
other groups as they are separate contemporary groups.
ADG: The average daily gain during the RFI test
ADG Ratio: Ratio with 100 being average, calculated per group for comparison.
RFI: the RFI value calculated from the bull’s actual feed intake on test
RFI RANK: The RFI rank within each group with 1 being best.
The GrowSafe System at RJM Feeders
