September 2009 Articles

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The FYI on RFI

The FYI on RFI As corn prices continue to soar, feed efficiency is more important than ever – for every segment of the beef industry. With 70 to 80 percent of the total variable cost for beef production coming from feed costs, the slightest improvement in feed efficiency can have a significant impact on profitability. Feed efficiency, however, is one of the most difficult traits to measure in beef cattle. It involves measuring the exact amount of feed each animal consumes in a time period and how much weight was gained in that period – a very labor-intensive process. Since most cattle are fed in groups, these measurements are not possible unless each animal is fed individually. A company from Canada has a solution to this problem. This company markets a system, called GrowSafe, which automates the process of collecting feed intake data. Through the use of computers, electronic scales on each feeder and electronic ID tags, the system can accurately measure the amount of feed consumed by each animal in a pen. This new system has greatly increased the capability of research institutions to conduct research on the genetic control of feed efficiency. This research has resulted in several DNA-based tests to predict feed efficiency in beef cattle. Scientists have also changed the way feed efficiency is scored and reported. In the past, feed efficiency was usually reported in pounds of feed consumed per pound of gain or the feed-to-gain ratio. Scientists now commonly report feed efficiency as residual feed intake or RFI. RFI (also called net feed efficiency) describes how an animal’s feed intake differs from its expected feed intake based on its maintenance and growth requirements. Low RFI is more desirable than high RFI, since an animal with a low RFI will either eat less with the same gains or gain more from the same amount of feed. Dry matter intake or DMI defines an animal’s genetic potential to consume feed, which is key for predicting feedyard performance or maintenance energy requirements. Cow-calf producers can, for example, use the analysis for RFI to help identify animals that gain well while consuming less feed – or can eat less but still produce a calf each year and maintain a desirable body condition score. The feedyard operator can use the traditional DMI values to help calculate the cost of gain for a pen of animals at closeout but can still evaluate RFI information as well. With the use of DNA technology, producers can now evaluate multiple traits related to feed efficiency – residual feed intake (RFI) and dry matter intake (DMI) – early in each animal’s life. A nice fact sheet on RFI is available from Alberta Agriculture Food and Rural Development at http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex10861/
$file/420_11-1.pdf. With Permission: University of Arkansas