Residual Feed Intake
For many years, genetic selection programs have focused on production traits (outputs), with little attention given to production costs (inputs). Within any beef cattle operation, feed costs are a big concern, since they typically account for 60 - 65% of total production costs. Escalating feed costs, and state of the art technology developed by GrowSafe Systems Ltd. has renewed interest in measuring feed efficiency in terms of residual feed intake.
Historically the way cattle people measure feed efficiency is feed to gain ratio. Feed to gain is a good pen measurement but if you want to know how efficient an individual animal is; it will likely give you a confusing result as this ratio is tied both to intake and rate of gain. For a genetic selection program, feed to gain is just not accurate enough.
In 1963, residual feed intake (RFI) was first proposed as an alternate measure of feed efficiency by US researchers (Koch et al). In contrast to feed to gain ratios, residual feed intake is independent of growth and maturity patterns. RFI is a more sensitive and precise measurement of feed utilization, since it is based on energy intake and energy requirements. RFI is defined as the difference between actual feed intake and the expected feed requirements for maintenance of body weight and for weight gain.
Simply stated, Actual feed intake - Estimated feed intake = Residual feed intake:
-
Efficient animals eat less than expected and have a negative or low RFI.
-
Inefficient animals eat more than expected and have a positive or high RFI.
-
Like a golf score, a low or negative RFI score is what you are aiming for.
To calculate RFI requires the measurement of actual feed intake. Back in 1963 this meant that you had to hand feed individual animals and then manually record what was actually eaten. The concept of RFI had huge potential but on a commercial scale lay dormant until technology advanced enabling electronic feed intake measurement.
In 2000 researchers in Canada (Basarab et al) began using GrowSafe technology to measure RFI. GrowSafe automation made measurement of RFI economically and practically viable. In 2003 a three-year project to undertake RFI in commercial centers began. This study showed the relationship between RFI and carcass characteristics, body composition, heat production, methane and manure production. This research was one of the first to uncover the true economic potential associated with selecting beef cattle for RFI. (CLICK HERE to link to results of this 3 year project)
Results from Australian, Canadian and US researchers suggest that selection for residual feed intake will improve feed efficiency without adversely affecting growth, carcass quality, cow efficiency or cow reproductive performance. Research has shown that selection for low RFI can have significant results:
-
Reduction of feed intake by up to 12% . In some animals this means a reduction of feed intake of 3 to 5 pounds per day. Over a 112 day feeding period at today's feed costs this means feed savings of up to $80 per animal
-
Lower maintenance of the cow herd by 9 to 10%
-
Have no effect on average daily gain or mature cow size
-
Slow gain in empty body fat by 4 per cent but will still grade choice.
-
Improve calf weight per cow feed intake by 15 per cent
-
Lower methane emissions by 25 to 30%
Considerable variation in RFI exists among individual animals within breeds or genetic strains. This variation suggests that substantial progress can be made in feed efficiency since the heritability of the trait is about 40 per cent. As 80 to 90 per cent of the genetic improvement in a herd comes through the sires, buying a feed efficient bull will make a big difference to your bottom line.
GrowSafe Equipped RFI Testing Centers
RFI is an individual record, taken in long term feeding trials (at least 70 days) where animals are housed in commercial group pens, and accurate measurements are made of daily feed consumed, as well as average daily gain.
GrowSafe equipped test centers use a scientifically determined protocol to measure RFI. When you buy a GrowSafe feed efficient bull tested in the following centers you are assured of accurate measurements consistent within, between and across tests.
Next RFI tested Bull Sale - March 27, 2008
Testing capacity is available in other centers located in:
Florida, Montana, Wyoming, Illinois and Missouri
For more information about these and other GrowSafe equipped centers contact us by Email at: mailto:als@growsafe.com
Braunvieh Association of America - National Bull Test and Sale
The inaugural National Braunvieh Performance Bull Test is currently underway at the Green Springs Bull Test Center in Nevada, Mo. This program program strives to promote and market Braunvieh bulls to profit minded cattle producers who retain ownership of their calves through the feedyard and sell carcasses on the grid. This is the first 'breed wide' national performance test including RFI in the US. For further information CLICK HERE to visit the Braunvieh Association of America website.
| 
