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Advancing Breed Composition Codes for Crossbred Dairy Cattle Calving Ease Analysis

Explore storing breed composition data, investigating calving ease with Brown Swiss and Jersey sires, utilizing crossbred records, and analyzing sire breed effects for improved genetic evaluation of dairy cattle.

brennan-saunders
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Advancing Breed Composition Codes for Crossbred Dairy Cattle Calving Ease Analysis

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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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