# Presentation: 686137

## Investigation of Herds Years with Abnormal Distributions of Calving Ease Scores

## The Problem

- Herds with unusual distributions of data affect evaluations of bulls
- Worst case is when large share of records for a bull are in one “bad” herd
- Herd reporting changes over time

## Percentage of Score by Parity In All Herds

**0**

**10**

**20**

**30**

**40**

**50**

**60**

**70**

**80**

**90**

**100**

**1**

**2**

**3**

**4**

**5**

**Calving Ease Score**

**Counts by Herd-Parity (%)**

**Parity 1**

**Parity 2+**

## Example of a Problem Bull

**  ****Herd               1              2              3              4              5          Total**
**--------        --------       --------       --------       --------       --------       --------**
**23050186         2 (100)        0 (  0)        0 (  0)        0 (  0)        0 (  0)        2 (  1)**
**23380528         1 (100)        0 (  0)        0 (  0)        0 (  0)        0 (  0)        1 (  1)**
**23600003         1 (100)        0 (  0)        0 (  0)        0 (  0)        0 (  0)        1 (  1)**
**23600175         1 (100)        0 (  0)        0 (  0)        0 (  0)        0 (  0)        1 (  1)**
**32460821        12 ( 18)        0 (  0)        5 (  8)        1 (  2)       48 ( 73)       66 ( 34)**
**          ****-----------------------------------------------------------------------------------------------**
**              ****1380 ( 57)      467 ( 19)      410 ( 17)       76 (  3)       78 (  3)     2411**
**          ****-----------------------------------------------------------------------------------------------**
**33130011         1 ( 14)        2 ( 29)        4 ( 57)        0 (  0)        0 (  0)        7 (  4)**
**33130548         4 (100)        0 (  0)        0 (  0)        0 (  0)        0 (  0)        4 (  2)**
**33980149         2 ( 67)        1 ( 33)        0 (  0)        0 (  0)        0 (  0)        3 (  2)**
**34470727         1 (100)        0 (  0)        0 (  0)        0 (  0)        0 (  0)        1 (  1)**
**35100522         0 (  0)        1 ( 50)        0 (  0)        1 ( 50)        0 (  0)        2 (  1)**
**35100639         4 ( 67)        2 ( 33)        0 (  0)        0 (  0)        0 (  0)        6 (  3)**
**.                .              .              .              .              .              .  **
**.                                .                             .                            .                            .                            .                             .  **
**.                                .                             .                            .                            .                            .                             .  **

**Example of a Problem Bull**

## Concept

**Identify ‘outlier’ herds**
**Remove that data**
**Determine if evaluation is ‘better’**
**Trade-off between edits for bad data and overall loss of data**

## Test Edits

**Exclude herds with abnormal distributions of scores**
**Abnormal herds defined by multinomial likelihood**
**Population frequencies for parity groups (1 vs. 2+) used for expected values**
**Herd test statistics calculated within parity (1 vs. 2+) and summed**

## GOF Statistics

**Multinomial distribution likelihood ratio with ‘expected’ distribution adjusted for herd size**
** **

## Predictability of Future Evaluations

**Compare evaluations from complete data to evaluations from partial data**
**Partial data truncated by:**
**Date of calving**
**Goodness of Fit (GOF) exclusion**

## Strategy for Herd Exclusions 

**Adjacent herd-years also excluded if exceed a less extreme threshold**
**5-fold difference in likelihood**
****** ****A future evaluation could potentially have fewer records than a previous run!**

## Example Herd 1

**year    c1_1    c1_2    c1_3    c1_4    c1_5    sumh1    c2_1    c2_2 c2_3    c2_4    c2_5    sumh2         gof    drop**
**1996       0      0       0       0       1        1        0      1  79      0       2       82      -214.07      1**
**1997       0      0       0       0       0        0        0      0 224      1       8      233     -1190.18      1**
**1998       0      0      34       0       0       34        0      0 304      0       3      307      -866.92      1**
**1999       0      0      60       0       4       64        0      0 290      0       3      293      -862.84      1**
**2000       0      0       3       0       0        3        0      0 213      0       0      213      -545.39      1**
**2002      21      0       0       0       0       21       87      0 150      0       0      237      -241.89      1**
**2003     100     15       8       4       1      128      322      6   7      2       0      337       -59.50      0**
**2004     148     15      13       3       1      180      273      8   0      0       0      281       -72.15      0**

## Example Herd 2

**year    c1_1    c1_2    c1_3    c1_4    c1_5    sumh1    c2_1    c2_2 c2_3    c2_4    c2_5    sumh2         gof    ****drop**
**1995      15       1       0      0       0       16       25       1   0      0       0        26      -1.917      0**
**1996      98      39       9      2       0      148      425      27   3      0       0       455     -49.103      0**
**1997     188      66      64      4       0      322      545     100  38      1       1       685     -41.237      0**
**1998     307      66      90     22       0      485     1382     168 113     12       4      1679     -36.192      0**
**1999     407     115      97      9       3      631     1597     170 105      8       3      1883     -63.533      0**
**2000     372     183     183      4       1      743     1343     258 141      4       8      1754    -110.008      1**
**2001     341     293     184      1       7      826     1078     513 198      4       6      1799    -346.880      1**
**2002     219     258     171      2       7      657      923     596 162      6       2      1689    -468.204      1**
**2003     165     309     183      5       4      666      652     590 242     14       6      1504    -657.263      1**
**2004     273     261     126      3       5      668      804     385 181     10       8      1388    -251.784      1**

## Percentage of Score by Parity In All (AN) and GOF4 Excluded (AG) Herds

**0**

**10**

**20**

**30**

**40**

**50**

**60**

**70**

**80**

**90**

**100**

**1**

**2**

**3**

**4**

**5**

**Calving Ease Score**

**Counts by Herd-Parity (%)**

**Parity 1 - AN**

**Parity 2 - AN**

**Parity 1 - AG**

**Parity 2 - AG**

## Conclusions

**GOF test excludes herds with poor score distribution uniformly across herd size**
**Exclusion of herds results in loss of evaluations for some bulls**
**Exclusion of data is expected to improve run to run stability**

## Remaining Issues

**Optimum amount of data to exclude**
**Evaluate different fractions of data removal**
**Recently submitted test run to InterBull with 1.5% data excluded**
**Will likely move to 7% data discarded**
**Will conduct sensitivity analysis to assess optimal data discard**
**Current InterBull test run for calving ease**

## Frequency of Codes in Combined Interbull File

| Code | Source | Official Report |  | Frequency | Percent |  | Cumulative |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  |  |  |  |  |  |  | Frequency | Percent |
|  |  |  | Sire Calving Ease |  |  |  |  |  |
| C | From correlation | No |  | 5367 | 4.77 |  | 5367 | 4.77 |
| D | Domestic | No |  | 15,073 | 13.40 |  | 20,440 | 18.17 |
| D | Domestic | Yes |  | 26,049 | 23.15 |  | 46,489 | 41.32 |
| I | Interbull | Yes |  | 22,809 | 20.27 |  | 69,298 | 61.59 |
| P | Sire MGS Indices | Yes |  | 43,208 | 38.41 |  | 112,506 | 100.00 |
|  |  |  | Daughter Calving Ease |  |  |  |  |  |
| C | From correlation | Yes |  | 10,792 | 9.59 |  | 10,792 | 9.59 |
| D | Domestic | No |  | 15,073 | 13.40 |  | 25,865 | 22.99 |
| D | Domestic | Yes |  | 26,049 | 23.15 |  | 51,914 | 46.14 |
| I | Interbull | Yes |  | 17,384 | 15.45 |  | 69,298 | 61.59 |
| P | Sire MGS Indices  | Yes |  | 43,208 | 38.41 |  | 112,506 | 100.00 |