CGs to EPDs 2006 BIF Symposium Sponsored by Ultrasound Guidelines Council Dr. Lisa A. Kriese-Anderson Auburn University

Would you purchase a bull ….

Would you purchase a bull …. This top young son of Superbull had a weaning weight of 636 lbs

Would you purchase a bull …. An exceptional prospect with a scrotal circumference of 35 cm This top young son of Superbull had a weaning weight of 636 lbs

So, why would you consider….

So, why would you consider…

So, why would you consider…

Ultrasound Basics Individual ultrasound measurements (adjusted) are as useful as individual weights and measures Really only mean something within the group they came from Ratios are better EPDs for ultrasound or carcass are best for selection decisions

Ultrasound Genetics Refresher Ultrasound measurements should be taken the same time as yearling weights Generally 320/330 to 410/430 days of age BIF says 335 to 395 days Entire contemporary group should be measured by a certified ultrasound technician Genetically, ultrasound measurements for carcass traits are highly correlated to actual carcass traits But they are not the same traits

Ultrasound Genetics Refresher Genetic Correlation Estimates Among Yearling Ultrasound and Carcass Traits UBF and BF 0.75 to 0.80 UREA and REA 0.70 to 0.75 IMF and Marbling 0.60 to 0.68

Ultrasound Genetics Refresher Genetic Correlation Estimates Among Yearling Ultrasound and Carcass Traits UBF and BF 0.75 to 0.80 UREA and REA 0.70 to 0.75 IMF and Marbling 0.60 to 0.68 Reminder – if you do not report any carcass data, individual animal accuracy can only be a high as the genetic correlation

Genetic Evaluation Begins with P = G + E

In Genetic Evaluation E ≈ Contemporary Group

Contemporary Group A contemporary group is a group of animals with the same: Herd Sex Birth Season Weigh date Management The largest contemporary group is at birth. All subsequent traits are subsets of the birth contemporary group.

SD = Selection Differential SD = (individual – avg of group) In Simplest Terms: BV = h2 x SD SD = Selection Differential SD = (individual – avg of group)

Example Data No Sire Dam CG WW PW REA BF IMF 6001 1 100 781 486 11.5 0.30 4.25 6002 101 626 522 0.21 4.21 6003 2 102 845 357 11.3 0.28 4.35 6004 103 713 482 11.2 0.18 2.89 6005 104 663 397 10.1 0.17 4.59 6006 3 105 720 532 10.6 0.44 5.20 6007 106 539 12.5 0.19 3.82 6008 4 107 841 562 15.1 0.32 3.90 6009 108 865 510 11.9 0.31 4.44

Data Analysis Multiple-trait animal model WW, PWG, UREA, UBF, %IMF in analysis Examine Sire Rankings for above traits

Sire EPD Rankings Trait WW Milk PWG UREA UBF IMF 4 2 1 3

Example Data – Just 1 CG No Sire Dam CG WW PW REA BF IMF 6001 1 100 781 486 11.5 0.30 4.25 6002 101 626 522 0.21 4.21 6003 2 102 845 357 11.3 0.28 4.35 6004 103 713 482 11.2 0.18 2.89 6005 104 663 397 10.1 0.17 4.59 6006 3 105 720 532 10.6 0.44 5.20 6007 106 539 12.5 0.19 3.82 6008 4 107 841 562 15.1 0.32 3.90 6009 108 865 510 11.9 0.31 4.44

With Wrong CG Definitions Do not have correct comparisons in data Sires are compared in “head to head” competition that were not Basics of EPD analysis is to find the group average and subtract the individual measurement from it Group mean is wrong!

Comparing Sire Ranks – Wrong CG Trait WW Milk PWG UREA UBF IMF 4 2 1/3 2/1 1/2 1 3/1 4/3 2/4 3/2 2/3 3/4 4/2

Not Reporting All Data No Sire Dam CG WW PW REA BF IMF 6001 1 100 781 486 11.5 0.30 4.25 6002 101 6003 2 102 845 357 11.3 0.28 4.35 6004 103 713 482 11.2 0.18 2.89 6005 104 663 397 10.1 0.17 4.59 6006 3 105 720 532 10.6 0.44 5.20 6007 106 539 12.5 0.19 3.82 6008 4 107 841 562 15.1 0.32 3.90 6009 108 865 510 11.9 0.31 4.44

By Not Reporting All Data If not sending in “bottom-performing” cattle, penalize the rest Group means are incorrect once again Competition is not reported accurately

By Not Reporting All Data Trait Mean – All data Mean-Select Data WW 753 ± 85 lbs 769 ± 75 lbs PWG 487 ± 68 lbs 483 ± 72 lbs UREA 11.7 ± 1.4 sq in 11.8 ± 1.5 sq in UBF 0.27 ± .09 in IMF 4.2 ± .63% 4.2 ± .67%

Sire EPD Ranks – Incomplete Data Trait WW Milk PWG UREA UBF IMF 4 2 1/3 2/1 1 3/1 1/2 3 3/2

Not Reporting All Data No Sire Dam CG WW PW REA BF IMF 6001 1 100 781 486 11.5 0.30 4.25 6002 101 6003 2 102 845 357 11.3 0.28 4.35 6004 103 713 482 11.2 0.18 2.89 6005 104 663 6006 3 105 720 532 10.6 0.44 5.20 6007 106 539 12.5 0.19 3.82 6008 4 107 841 562 15.1 0.32 3.90 6009 108 865 510 11.9 0.31 4.44

Sire EPD Ranks – Incomplete Data Trait WW Milk PWG UREA UBF IMF 4 2 1/3 2/1 1 3/1 1/2 3 3/2 2/3

Final Comments Actual ultrasound data needs to be treated the same as actual data from any other trait Must be in a comparison mode (Ratio/EPD) For use within a contemporary group May be helpful to divide data into thirds Always remember there can be measurement error. Don’t believe in absolutes

Field Certification Trait SEP SER Bias Corr Rump/Back Fat ≤0.1 ≥0.85 Ribeye Area ≤1.2 ≥0.80 Percent IMF ≤0.7 ≥0.70

Final Comments Proper reporting of contemporary groups is essential P = G + E is the basis for all genetic evaluation Don’t selectively report data Only penalizing the top animals Only hurting yourself Don’t let a trait you may not be able to visualize well keep you from doing the right thing

Additional Items If a breed publishes both ultrasound and carcass EPD values, want ultrasound and carcass EPDs to be similar: Trait Ultrasound Carcass REA 0.26 0.36 IMF 0.27 Bull 16 Trait Ultrasound Carcass REA 0.33 -0.04 IMF 0.46 0.10 Bull 110

Additional Items If breed published just carcass and you collect/report no carcass info, accuracy will only be as high as genetic correlation Don’t single trait select!