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Current Projects: Dr. Ignacy Misztal

Reducing data loss and improving accuracy in National Cattle Evaluation

Research project: "Using a Random Regression Model to Evaluate Growth Traits in a Beef Cattle Population"

Current genetic evaluations for beef cattle populations in the U.S. utilize a multiple trait model for growth traits to predict Expected Progeny Differences (EPDs). Weights are taken at industry recommended ages that include birth, 205-day (weaning) and 365-day (yearling). Acceptable age ranges are established for each measurement and data on animals measured outside these ranges are lost during the editing phase and excluded from the genetic evaluation. Breeders and breed associations have long expressed interest in finding a way to include animals in these evaluations that fall outside of the acceptable age ranges.

Research at UGA has shown that using a Random Regression model would allow for records measured outside the acceptable range to be incorporated into the analysis. Including animals whose data were taken outside the standard age range would decrease the number of records lost in editing and increase the accuracy of the evaluation.

The goal of this project is to put into production a Random Regression model to evaluate growth EPDs for both multibreed and single breed analyses. The results are to be compared with current multiple trait analyses and the results will be provided to breed associations for review.


Research Team (all from University of Georgia except as noted)

Dr. Keith Bertrand, Project Director
Breeding and Genetics

Dr. Andra Nelson
Breeding and Genetics

Dr. Ignacy Misztal
Breeding and Genetics

Dr. Shogo Tsuruta
Breeding and Genetics

Dr. Brett Middleton
Breeding and Genetics

Dr. Romdhane Rekaya
Breeding and Genetics

Dr. Juan Pablo Sánchez (Universidad de León, Spain)
Breeding and Genetics