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Revised estimates of lifetime Net Merit for dairy breeds and breed crosses

Revised estimates of lifetime Net Merit for dairy breeds and breed crosses. Introduction. Previous estimates used net merit (NM$), cheese merit (CM$), and fluid merit (FM$) formulas from 2000

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Revised estimates of lifetime Net Merit for dairy breeds and breed crosses

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  1. Revised estimates of lifetime Net Merit for dairy breeds and breed crosses

  2. Introduction • Previous estimates used net merit (NM$), cheese merit (CM$), and fluid merit (FM$) formulas from 2000 • Dairy breeds and breed crosses were compared using updated NM$, CM$, and FM$ formulas that include daughter pregnancy rate (DPR), calving ease, and stillbirth

  3. Data and Methods • National data for milk, fat, protein, productive life, SCS, and DPR were each evaluated using an all-breed animal model • New estimates of breed differences were compared to phenotypic breed differences and to previous estimates from studies that only included herds containing crossbred cows

  4. Breed Effects and Heterosis • New estimates of breed differences were generally intermediate between the previous estimates and the phenotypic breed differences; all three estimates were similar • Estimates of general heterosis from previous studies were used in the current research and not re-estimated

  5. Breed Effects and HeterosisTransmitting ability differences from Holstein Heterosis and DPR estimates are from previous research

  6. Other Trait Estimates • Body size composite estimated from mature weight • Udder composite, Feet & Leg composite extrapolated from regressions on other traits within Holsteins • Size, PL, milk, DPR, SCS • Breed means for calving ease and for stillbirth • 7.3 million HO, 37000 JE, 17000 BS, 2000 GU, 2000 AY, 300 MS

  7. Trait Correlations within Holsteins(and Jersey correlations for comparison)

  8. Assumed Effects – Other TraitsTransmitting ability differences from Holstein

  9. Net Merit Relative Emphasis DPR = daughter pregnancy rate (fertility), CA$ is index of calving ease and stillbirth

  10. NM$, FM$, CM$ - Economic Values Other values are same in each index: PL 29, SCS -150, Size -14, Udder 28, F&L 13, DPR 21, CA$ 1

  11. Merit of F1 Holstein Crossbreds Compared to 2005 genetic base for Holstein

  12. Later Generation Crosses Compared to 2005 genetic base for Holstein

  13. “Exotic” Breeds • US has pedigree records for other breeds; but very little production data • For further information: • Interbull conversions to Ayrshire base • U. Minnesota scientists (Heins et al.)

  14. Conclusions • Breed effects were re-estimated • Yield, PL, SCS, DPR by all-breed model • Udder, F&L composites from other traits • Calving ease and stillbirth breed means • New Net Merit formula for August 2006 • Holsteins still superior for FM$

  15. Conclusions • HO x BS and HO x JE higher for NM$ and CM$ • BS x JE higher than HO for CM$ • Three breed crosses (HO, BS, JE) are higher than HO backcrosses for CM$, similar for NM$

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