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Breed Composition Codes for Crossbred Dairy Cattle with an Application to Calving Ease

Breed Composition Codes for Crossbred Dairy Cattle with an Application to Calving Ease. Objectives. Develop a system for storing breed composition data in a national database.

brennan-saunders
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Breed Composition Codes for Crossbred Dairy Cattle with an Application to Calving Ease

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  1. Breed Composition Codes for Crossbred Dairy Cattle with an Application to Calving Ease

  2. Objectives • Develop a system for storing breed composition data in a national database. • Investigate a breed-of-sire calving ease evaluation for Brown Swiss and Jersey sires using purebred and F1 daughters.

  3. Options for Crossbred Evaluation • Use crossbred records in a breed-of-sire evaluation. • Use records from all animals in a single across-breed evaluation. • Do not use the records (the current system).

  4. Crossbred Table • 338,968 animals • Animal identification • Breed fractions for 18 dairy breeds • Four-generation breed stack • Sire breed stack • Heterosis value

  5. Crossbred Table • The four-generation breed stack allows identification of crossbred sires. • The sire breed stack summarizes the breeds of the sire and the dam's male ancestors up to 24 generations.

  6. Non-zero Breed Fractions

  7. F1 for each Breed Cross

  8. Calving Ease • Sire-MGS threshold model • Breed-of-sire evaluation • Fixed breed effect to distinguish between purebred and F1 calvings

  9. Calving Ease Data • CE records from 1998 to 2003 • 11,793 BS and 3443 BS-sired F1s • 65,293 JE and 7095 JE-sired F1s • Herds with only one observation or only difficult calvings were excluded

  10. BS Threshold Model Solutions Effect Levels Range SD Herd-year 2366 3.89 0.36 Year-season 12 0.96 0.26 Parity-gender 6 0.88 0.31 Sire birth year 6 0.16 0.05 Maternal-grandsire birth year 11 0.76 0.22 Breed composition 2 0.16 0.11 Sire 131,387 0.48 0.01 Maternal grandsire 131,387 0.49 0.01

  11. BS Service Sire and Daughter PTA for %DBH by Birth Year of Bull

  12. Distribution of BS Service Sire and Daughter PTA for %DBH

  13. JE Threshold Model Solutions Effect Levels Range SD Herd-year 3405 4.03 0.41 Year-season 13 5.28 1.38 Parity-gender 6 0.54 0.21 Sire birth year 5 0.13 0.05 Maternal-grandsire birth year 7 0.31 0.11 Breed composition 2 0.49 0.35 Sire 131,385 0.45 0.01 Maternal grandsire 131,385 0.38 0.01

  14. JE Service Sire and Daughter PTA for %DBH by Birth Year of Bull

  15. Distribution of JE Service Sire and Daughter PTA for %DBH

  16. Conclusions • Crossbred animals can be rapidly identified using the new database. • It is feasible to use crossbred records in genetic evaluation. • There is no genetic trend for calving ease in BS or JE. • Future analyses will include breed effects for service sires and dams.

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