Adsa05 Pvr

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Adsa05 Pvr

  1. 1. Productive Life Including All Lactations, Longer Lactations, and Calf Value
  2. 2. Goals <ul><li>Allow credit for longer lactations in productive life (PL) Tsuruta et al, 2005, JDS 88:1156 </li></ul><ul><li>Update factors that predict PL for cows still alive (censored cows) </li></ul><ul><li>Improve the PL trait definition by considering lactation curves </li></ul>
  3. 3. Data Sets <ul><li>Variance estimation from AIPL data </li></ul><ul><ul><li>1,098,329 Holsteins born 1994  97 </li></ul></ul><ul><ul><li>5109 sires with relationship matrix </li></ul></ul><ul><ul><li>10 mo, 12 mo, or unlimited length </li></ul></ul><ul><ul><li>2-mo calf value also considered </li></ul></ul><ul><ul><li>Data censored at 36 to 84 mo of age </li></ul></ul><ul><li>Herds with complete lactations from DRMS history file </li></ul>
  4. 4. PL Heritabilities and Correlations Lactation limit (mo) .068 +Calf .992 .067 No limit .961 .956 .069 12 mo .963 .957 .998 .073 10 mo +Calf None 12 10 h 2
  5. 5. Correlation of PL with Protein Phenotypic = .33 1993, Genetic = .46 JDS 76:2758 .11 .12 .03 .00 Genetic .19 .20 .17 .16 Phenotypic No limit + calf credit No limit 12 mo 10 mo Correlation with protein
  6. 6. Early Measures of PL 10-mo limit .16 .17 .21 .25 Phenotypic correlation w/1st-parity protein 1.00 .99 .97 .87 Genetic correlation .00 .02 .09 .21 Genetic correlation w/1st-parity protein .073 .065 .048 .018 Heritability Censoring age PL statistic Final 6 yr 4 yr 3 yr
  7. 7. Distribution of Months Until Culling 1 st -parity cows
  8. 8. Lactation Curve yield = 5.9 + 9.5e [.059(1  e  .047*t )/.047  .0018*t] 35 25 20 15 10 5 0 30
  9. 9. First- and Later-Parity Shapes
  10. 10. Current PL Credits 2 0 3 4 5 1 Years 20 140 40 60 80 100 120 0 Credit (%) 3 2 1
  11. 11. Possible PL Credits 2 0 3 4 5 1 Years 20 140 40 60 80 100 120 0 Credit (%) 3 2 1
  12. 12. Proposed PL Credits .63 .70 .78 .89 1.00 1.15 1.31 .95 3+ .59 .66 .74 .83 .95 1.08 1.23 .89 2 .59 .64 .70 .76 .82 .90 .95 .66 1 15 13 11 9 7 5 3 1 Parity Month of lactation
  13. 13. Conclusions <ul><li>PL parameters are changing across time </li></ul><ul><ul><li>Phenotypic correlations are fairly stable </li></ul></ul><ul><ul><li>Genetic correlations have declined rapidly </li></ul></ul><ul><li>PL at 36-mo censoring has less info </li></ul><ul><ul><li>Heritability is lower than 1993 estimate </li></ul></ul><ul><ul><li>Genetic correlation with final PL = .87 (vs .92) </li></ul></ul><ul><li>Can increase lactation length limit in PL to 12 mo or use lactation curve credits </li></ul>

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