The Feed Intake Monitoring System

Wardens Farm has made a gift to the Iowa State University Animal Science department and that is the new feed intake monitoring system (FIMS) that was developed in 2005 by the Iowa Beef Center.  This FIMS system allows us to get individual feed intakes on a ration similar to what is used by the feedlot industry to finish steers.  The FIMS system was reconfigured so it has 7 pens set up to handle 6 bulls per pen with each pen containing a feed bunk-scale system and waterer. The Iowa Beef Center in cooperation with three companies (Id-ology out of Wisconsin, Scale Source and Mirafont in Iowa) designed and oversaw the installation of the system. The Iowa Beef Center has developed software which summarizes the intake data and calculates feed conversion and residual feed intake on all the bulls.

Sixty-three bulls were tested each year in 2006 and 2007 for an 84-day period.  In 2008 a total of 41 bulls are being tested under the supervision of Iowa Beef Center staff.  During the remaining part of the year, beef research faculty at ISU will be using the system in their research programs. 

Background on Residual Feed Intake (RFI)

Researchers have known for years that direct selection for feed efficiency (measured as pounds of feed per pound of gain) has some potential drawbacks.  One issue is that feed efficiency is highly correlated with average daily gain; this suggests that selection for high growth alone is much more cost-effective than going through the hassle of measuring individual feed intake.  Another problem is that this crude measure of feed efficiency would tend to select for animals with greater muscle mass and less fat deposition.  This is because a pound of muscle contains far less energy than a pound of fat, and it therefore requires less feed to build muscle than fat tissue.  While at certain points in the growth curve this may not be a problem, if feed efficiency is measured through maturity, carcass quality could be harmed by selection for feed efficiency.  Finally, selecting for increased average daily gain results in increased mature size; increasing the size and energy requirements of brood cows is not a goal of most operations.

Residual feed intake (RFI) is becoming widely accepted as a more valuable tool for genetic selection for feed efficiency.  RFI is defined as the amount of feed eaten daily compared to what that animal is expected to consume based on results from the contemporary group in which it was raised.  Something called regression analysis on the entire contemporary is used to arrive at the expected consumption equation and then that is compared to what the animal actually consumes.  This expected intake value is then compared to the actual daily intake for the individual to determine the RFI value.

Example values:

Interpreting and Utilizing RFI
Because of how RFI is defined, lower (negative) numbers indicate greater feed efficiency, while higher numbers indicate poorer feed efficiency.  RFI can be used for genetic selection with confidence; it is not correlated with average daily gain, body weight, body composition, or mature size, so you won't be unintentionally moving backwards on other traits as you improve feed efficiency.  However, like other performance values for which no EPD is available, RFI should only be compared across animals managed together (for example, one can select among Wardens Farm bulls using RFI, but these values are not useful for comparing with bulls from another operation).

Wardens Farm Angus Females in Research Project

The Question to Address:
Do heifers evaluated for feed efficiency from weaning to yearling have similar rankings in feed utilization for growth, milking ability, and rebreeding during the nursing stage with their first calves?   

Cooperating in this study is the Iowa Beef Center at Iowa State University, the ISU Department of Animal Science and the American Angus Association.  Because feed costs represent about 60% of the total cost to maintain a beef cow herd in the U.S. it is imperative that we learn how feed efficiency measured in various stages of development relate to producing cows.  Fortunately Wardens Farm currently evaluates heifer calves for feed intake and efficiency thus allowing a close examination of their efficiency later in life.

Each year for 3 years Wardens Farm will send calved out first-calf heifers to the ISU Beef Nutrition Farm where they will be drylotted and fed their daily rations using the feed intake monitoring system (FIMS) developed in conjunction with the Iowa Beef Center.  All heifers will be evaluated for feed intake, gain and resulting feed conversions and residual feed intake.  Additionally, all heifers will be evaluated for milk production level using the weigh-suckle-weigh technique. 

Measures of Outcome:
The outcome of this project would be to assess whether heifers evaluated as efficient in the growth and development stages would continue to be efficient as first-calf heifers during lactation.  Wardens’ heifers born in 2006 which were previously feed efficiency tested had a range in residual feed intake of 1.78 to -2.68 and a range in BIF adjusted feed to gain conversion of 6.62 to 20.90 lbs of dry matter per pound of gain.  Outputs measured as first-calf heifers will be pounds of calf weaned, degree of maintenance (body condition score and weight gain), and milk production.  These observations will be associated with total feed intake during this trial and efficiencies compared to those achieved during the growth and development phase.

As summary reports are prepared and published they will be linked to this Wardens Farm website page.  STAY TUNED.

Wardens Farm heifer in Pinpointer Feed Intake System.

Wardens Farm heifers on Pinpointer system in 2006.

Wardens Farm female on FIMS at Iowa State University, 2008.

Feed Intake Monitoring System, ISU Beef Nutrition Farm, Ames, IA