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

2. Would you purchase a bull ….

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

4. 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

5. So, why would you consider….

6. So, why would you consider…

7. So, why would you consider…

8. 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

9. 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

10. 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

11. 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

12. Genetic Evaluation Begins with P = G + E

13. In Genetic Evaluation E ≈ Contemporary Group

14. 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.

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

16. 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

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

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

19. 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

20. 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!

21. 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

22. 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

23. 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

24. 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%

25. 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

26. 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

27. 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

28. 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

29. 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

30. 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

31. 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

32. 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!