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Hot Topics: Researchers Advise Against IGF-I Use to Evaluate Feed Efficiency
Position Paper: "The Use of Insulin-like Growth Factor I (IGF-I) as an Indicator Trait in a Genetic Evaluation for Feed Efficiency"

Nutrient efficiency is of great importance to the beef cattle industry and the cost of collecting data is high, which is why NBCEC researchers looked into the use of related traits that are easily measured, specifically Insulin-like Growth Factor I (IGF-I), as an indicator trait for residual feed intake (RFI).

RFI addresses the biological efficiency of animals. Even though there is some evidence that RFI could be related to IGF-I, researchers associated with NBCEC do not recommend the current use of IGF-I as an indicator trait for use in a genetic evaluation of RFI.

The study points specifically to an inconsistency of IGF-I testing across breed types. Research also has indicated there are possible unfavorable relationships between low IGF-I and other economically relevant traits such as marbling and reproduction rates. Click here to read the full study.


  • Dr. John Pollak, Professor of Animal Science, Cornell University
  • Dr. Darrh Bullock, Extension Beef Specialist and Professor, University of Kentucky
  • Dr. Gordon Carstens, Associate Professor of Animal Nutrition, Texas A&M University
  • Dr. Rod Hill, Associate Professor of Growth Biology, University of Idaho
  • Dr. Tom Welsh, Professor of Reproductive Physiology, Texas A&M University
  • Dr. Mike Davis, Professor of Animal Science, Ohio State University