1. Introducing CDCB Health Evaluations
Kristen Parker Gaddis, CDCB Geneticist

2. Beginning in April 2018, CDCB will provide official genetic and genomic evaluations for six direct health traits.

3. What are the traits?

4. Selection of health events
Based on several considerations
Preliminary research
Incidence rate
Reporting consistency
Cost
Heritability

5. Health Event Definitions
Hypocalcemia: typically results after calving due to low total blood calcium levels; also commonly referred to as milk fever
Displaced abomasum: enlargement of the abomasum with fluid and/or gas which causes movement to the left or right side of the abdominal cavity, usually requiring veterinary intervention
Ketosis: build up of ketone bodies typically occurring due to negative energy balance in early lactation

6. Health Event Definitions (continued)
Mastitis: infectious disease causing inflammation of the mammary gland; one of the most common and costly diseases of dairy cattle
Metritis: infection of the endometrium (lining of the uterus) after calving
Retained placenta: retention of fetal membranes more than 24 hours after calving

7. Editing & Validating the data
Producer-reported data from U.S. herds
Editing procedures were researched and developed to ensure we are using the most accurate data
General phenotypic edits developed by AGIL researchers
Additional constraints put in place and outlined in peer-reviewed article*
Compared the incidences with those found in designed and large-scale studies
* Parker Gaddis et al., 2012

8. Trait statistics Calculated with research data from DRMS on Holsteins
Event
Incidence
Heritability*
Hypocalcemia
1.3%
0.6%
Displaced abomasum
2.1%
1.1%
Ketosis
3.9%
1.2%
Mastitis
10.2%
3.1%
Metritis
6.2%
1.4%
Retained placenta
3.6%
1.0%
* Heritability calculated on observed scale

9. How are these traits evaluated?

10. Genetic Evaluations
Using the same tested methods as other CDCB genetic and genomic evaluations
Developed by AGIL researchers
International validation with Interbull

11. Genomic Evaluations Uses same methods and programs as other traits
Same 60,671 markers used for routine genomic evaluations

12. How do these traits relate to current traits?

13. Current Traits We have been making progress in health traits
Indirect selection with productive life, livability, etc.
Correlations between PTAs for health traits and traits in NM$

14. PTA Correlations Event Protein PL LIV SCS DPR CCR HCR Hypocalcemia
0.18
0.15
0.19
-0.29*
0.003
0.01
0.02
Displaced abomasum
0.23
0.35*
0.47*
-0.13
0.32*
0.28*
0.24
Ketosis
0.03
0.33
0.27
-0.19
0.59*
0.49*
0.07
Mastitis
0.06
0.39*
0.22*
-0.68*
0.20*
0.21*
Metritis
0.05
0.26*
-0.09
0.46*
0.41*
0.23*
Retained placenta
-0.03
0.17*
0.13*
-0.10
0.14*
0.12*
* Significant P < 0.05

15. Relationships with current traits
No significant correlation with yield trait
Significant correlations with new health traits:
Productive life and Livability
Mastitis and SCS (-0.68)
Fertility traits

16. How will the traits be presented?

17. Trait Presentation Traits will be presented as disease RESISTANCE
Hypocalcemia resistance
Displaced abomasum resistance
Ketosis resistance
Mastitis resistance
Metritis resistance
Retained placenta resistance

18. Trait Expression
Percentage points of event incidence above or below the breed average
Higher, positive values = more resistant
Lower, negative values = less resistant

19. Examples Resistance of clinical mastitis ≈ 90% Bull A PTA = + 3.0
Incidence rate ≈ 10%
Bull A PTA = + 3.0
Bull B PTA = - 4.0
Expect 93% resistance of clinical mastitis among Bull A’s daughters (7% incidence rate)
Expect 86% resistance of clinical mastitis among Bull B’s daughters (14% incidence rate)

20. Economic Value
Utilizing the most recent estimates of direct treatment costs from literature
NM$ already accounts for related losses (e.g., decreased production and fertility)
Abnormal & sick test day adjustments
Liang categories: veterinary and treatment costs, producer labor, milk loss, discarded milk, culling cost, extended days open, and on-farm death

21. Estimated direct cost per case*
Economic estimates
Event
Liang
et al., 2017
Donnelly
Adjusted
test day
Estimated direct cost per case*
Hypocalcemia -
$38
- $4
$34
Displaced abomasum
$82
$275
+ $19
$197
Ketosis
$23
$33
+ $0
$28
Mastitis
$104
$39
+ $3
$75
Metritis
$94
$117
+ $7
$112
Retained placenta
$47
$80
+ $4
$68

22. Average Genomic Reliability
Event
Young bulls
Proven bulls
Hypocalcemia
40.0
44.2
Displaced abomasum
41.8
47.1
Ketosis
41.2
46.2
Mastitis
49.4
56.3
Metritis
42.2
48.1
Retained placenta
41.6
46.7

23. How can we keep improving?

24. No man…or cow?…is an island

25. Accurate health evaluations
Research
Dairy Records Providers
Dairy Records Processing Centers
Producer-reported health events
CDCB Working Groups
Collaboration with AGIL

26. Dairy Producers
The most critical component by actively reporting health events
Develop a robust national database
Collection of more data will improve evaluations

27. Data Security Security of raw data is of the utmost importance
Several levels of IT security put in place
Only PTAs will be published by CDCB based on data contributed to the cooperator database
Raw data or related information will never be released to third parties
Herd-based statistics will not be published

28. Dairy Records Providers & Processing Centers
Building a robust national database depends on transfer of the data to CDCB
Not a simple process
Collaboration & cooperation

29. Research & Development
AGIL – provided support, consultation, and countless hours of help in the process of development and testing
CDCB Working Groups – discussions and recommendations for critical decisions

30. Thank you! Dairy Producers DRPC’s and DRP’s CDCB committee members
AGIL

31. Thank You!