General Session III
Measuring Feed Efficiency:
Minimizing Inputs Across the Production Chain
BOZEMAN, Mont. (June 3, 2011) — Advances in cattle DNA marker technology have made University of Alberta research geneticist Stephen Moore optimistic about even wider application of marker panels for genetic selection within cattle breeds, and even across breeds. A presenter at the 43rd annual Beef Improvement Federation (BIF) research symposium, Moore talked about efforts to develop marker-assisted selection for feed efficiency as measured by residual feed intake (RFI).
Calculated as the difference between the amount of dry matter an animal actually consumes and the expected feed intake, RFI represents the weight and growth weight over a particular period. A low RFI is an indication that an animal meets performance expectations on less feed than would be expected. Moore said RFI has been shown to have considerable potential as an index of feed efficiency. Moderately heritable, the trait has drawn much attention in recent years as a means of selecting for improved efficiency without increasing mature body size.
The frequent measurement of individual animal feed intake and weight has been made easier with recent technology. However, Moore said diet, season of testing and animal maturity have been shown to influence RFI estimates. Time and equipment costs make phenotypic measurement for RFI expensive. The lower cost of a DNA test and the ability to make RFI estimates while animals are very young has spurred interest in developing marker-assisted selection tools for RFI.
Moore said a number of studies have attempted to develop marker panels for feed efficiency. He cited Canadian studies carried out at seven research facilities and the identification of 23 gene markers associated with RFI.
“We believe they explain about 18% of the phenotypic variation (for RFI) in the discovery herd, and validation is under way in a different cattle population,” Moore stated.
A factor common to previous studies is that markers generally performed better in the discovery herd than in other populations used to validate the markers.
“We have validated about half of the markers, but we still expect a much lower size of effect (in validation herds),” Moore admitted. “We should know in six months or so.”
According to Moore, the availability of higher-density marker panels for genotyping cattle will aid in finding markers for traits such as RFI, and should increase the potential for application across breeds as well as for evaluating cattle of a given breed.
To listen to this presentation and to view the proceedings paper and the PowerPoint that accompanied it, visit the Newsroom at www.BIFconference.com.
BIF’s 43rd Annual Research Symposium and Annual Meeting was hosted June 1-4 on campus at Montana State University, Bozeman, Mont.
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