1. J. B. Cole 1, P. D. Miller 2, and H. D. Norman 1 1 Animal Improvement Programs Laboratory Agricultural Research Service, USDA, Beltsville, MD 2 Department of Dairy Science University of Wisconsin-Madison, Madison, WI 2004 Genetic Improvement of Dairy Cattle Health

2. John B. Cole 2004 Overview Response to selection using field- recorded traits is efficient and well- documented. Herd owners are interested in healthy, longer-lived cows. Genetic variability exists for health traits of economic interest.

3. Genetic Improvement of Dairy Cattle Health John B. Cole 2004 Overview Statistical and computational tools for genetic evaluation exist. Data processing routines can be developed. However, data needed for routine evaluations are limited.

4. Genetic Improvement of Dairy Cattle Health John B. Cole 2004 Why select for improved health? Longer-lived (more profitable) cows. Decreased cost of production. Reduced herd turnover. Improved animal welfare. Genetic gains are cumulative!

5. Genetic Improvement of Dairy Cattle Health John B. Cole 2004 Desirable Properties of Health Traits Reasonably large genetic variability or heritability. Significant economic value. Reasonable cost of measurement and recording. Consistent methods for measurement and recording. (Shook, 1989)

6. Genetic Improvement of Dairy Cattle Health John B. Cole 2004 Challenges Low heritabilities for some traits. Unfavorable correlations with milk, fat, and protein yield. Affected animals have a low frequency of occurrence. Diagnoses may be uncertain. Data are not collected in a national database.

7. Genetic Improvement of Dairy Cattle Health John B. Cole 2004 Heritabilities and Correlations of Composite Health Traits (Lyons, Freeman, and Kuck, 1991) Reproduct.MammaryDigestiveLocomotiveRespiratory Reproduct.0.02±0.04-0.11*0.380.02-0.23* Mammary0.12±0.060.520.840.34 Digestive0.21±0.080.870.76 Locomotive0.16±0.070.74 Respiratory0.02±0.04 * Negative genetic correlations reflect undesirable relationship.

8. Genetic Improvement of Dairy Cattle Health John B. Cole 2004 Genetic Correlations Between Composite Health and Yield Traits (Lyons, Freeman, and Kuck, 1991) Milk YieldFat Yield Reproductive -0.27*-0.25* Mammary 0.18-0.06* Digestive 0.44-0.06* Locomotive 0.480.45 * Negative genetic correlations reflect undesirable relationship.

9. Genetic Improvement of Dairy Cattle Health John B. Cole 2004 Genetic Tools Currently Available Calving Ease: Easier calving, less dystocia, fewer stillbirths (h 2 =0.022). Daughter Pregnancy Rate: Improved female fertility (h 2 =0.040). Productive Life: Longer working life (h 2 =0.085). Somatic Cell Score: Improved resistance to mastitis (h 2 =0.100).

10. Genetic Improvement of Dairy Cattle Health John B. Cole 2004 Holstein Daughter Pregnancy Rate (%)

11. Genetic Improvement of Dairy Cattle Health John B. Cole 2004 Holstein Productive Life (mos)

12. Genetic Improvement of Dairy Cattle Health John B. Cole 2004 Format 6 The USDA Animal Improvement Programs Laboratory has drafted a data exchange format to collect health data. It includes standard health codes. The objective is to collect data for research. The goal is to facilitate selection for healthier cows.

13. Genetic Improvement of Dairy Cattle Health John B. Cole 2004 Format 6 Records Format 6 records include  Animal and herd identification  Up to 20 health event segments Cow records begin with a calving and end with disposal or the next calving. Heifer records begin at birth and end at first calving.

14. Genetic Improvement of Dairy Cattle Health John B. Cole 2004 Health Event Segment Health event code Health event date Health event detail (optional)

15. Genetic Improvement of Dairy Cattle Health John B. Cole 2004 Standard Health Event Codes Currently, no health event codes are used uniformly in dairy records systems. Standard codes have been developed based on frequency of occurrence in field data and consultation with veterinarians.

16. Genetic Improvement of Dairy Cattle Health John B. Cole 2004 Health Event Codes Cystic ovary Diarrhea/scours Digestive problem/off feed Displaced abomasum Downer cow Dystocia Johne’s disease (clinical) Ketosis/acetonemia Lameness Mastitis (clinical) Metritis Milk fever/hypocalcemia Nervous system problem Other reproductive problem Respiratory problem Retained placenta Stillbirth Teat injury Udder edema

17. Genetic Improvement of Dairy Cattle Health John B. Cole 2004 Most Frequent Health Events in DRMS Data FrequencyPercent of Events* Mastitis496,53119.27 Lameness128,8695.00 Metritis126,2694.90 Cystic ovary81,9363.18 Retained placenta57,6912.24 Digestive problem47,1561.83 Respiratory problem39,9181.55 Ketosis25,5410.99 Displaced abomasum21,9080.85 *Frequency and percent based on 2,577,004 health event observations.

18. Genetic Improvement of Dairy Cattle Health John B. Cole 2004 Management Events Three management traits are also in Format 6  Body condition score  Milking speed  Temperament The format can accommodate new traits  e.g. Locomotion score

19. Genetic Improvement of Dairy Cattle Health John B. Cole 2004 Optional Health Event Detail Details of problems of high economic impact (e.g. clinical mastitis)  There is one mastitis event code.  Organism and quarter may be reported. Other codes may also use this field  Dystocia: scores of 1 to 5.  BCS: scores of 1.00 to 5.00.

20. Genetic Improvement of Dairy Cattle Health John B. Cole 2004 Research Needs Data quality edits Individual versus composite traits Environmental factors affecting records Relationships among traits Variance components estimation Genetic evaluation models

21. Genetic Improvement of Dairy Cattle Health John B. Cole 2004 Summary Format 6 provides the framework for a national health database. Selection for improved health is possible and desirable. Selection complements advances in management and veterinary care.