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Correlations Among Measures of Dairy Cattle Fertility and Longevity. Longevity & Fertility Investigation. 1,062,791 c ows born 1992-1994 Daughters of 3080 Holstein sires Progeny tested bulls with > 60 daughters Older bulls to provide ties and relationships Compare two measures of longevity

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longevity fertility investigation
Longevity & Fertility Investigation
  • 1,062,791 cows born 1992-1994
  • Daughters of 3080 Holstein sires
    • Progeny tested bulls with > 60 daughters
    • Older bulls to provide ties and relationships
  • Compare two measures of longevity
    • Productive Life (max 10 mo / lactation)
    • Lifespan (first calving until death)
  • Develop new fertility evaluation
cow fertility data multi trait reml analysis
Cow Fertility DataMulti-trait REML Analysis
  • First lactation records
  • Days Open (DO) = Calving interval – 280d
  • Limits on DO
    • Lower limit of 50d
    • Upper limit of 250d
    • ‘Sold for reproductive problems’ DO = 250d
    • ‘Sold for other reasons’ DO = 150d (mean)
      • Cows sold for dairy not included
proposed usda fertility evaluation
Proposed USDA Fertility Evaluation
  • Lactations 1-5 beginning with 1960
  • Days Open data
    • Reported DO confirmed with next calving
      • Exclude most recent 9 months
    • Reported DO if no next calving
      • Exclude most recent 9 months
    • Calving interval – 280 days if no reported DO
      • Exclude most recent 18 months
    • Assigned DO = 250 if sold for infertility
distribution of days open holstein calvings 1990 2001
Distribution of Days OpenHolstein Calvings 1990 - 2001

Cows culled for reproductive reasons

≤ 50

≥ 250

holstein phenotypic trend
Holstein Phenotypic Trend

Lactation

5th

4th

3rd

2nd

1st

proposed evaluation methods
Proposed Evaluation Methods
  • BLUP Animal Model
  • Same programs used for yield, PL, SCS
  • Adjust for heterogeneous variance
  • Parameter estimates used:
    • Heritability = 4%
    • Repeatability = 11%
    • Sire-by-herd interaction = 1%
evaluation test run
Evaluation Test Run
  • Holstein data from May 2002 evaluation
    • 36 million lactations
    • 14 million cows
  • Statistics for recent, well-sampled bulls
    • Born 1994 - 1997
    • Milk REL > 80% (mean = 87%)
    • 4215 Holstein bulls
    • 314 Jersey bulls
days open trends
Days Open Trends
  • Phenotypic trend 1960 - 1998

Holstein: +37 days

Jersey: +20 days

  • Genetic trend 1960 - 1998

Holstein: +17 days

Jersey: +9 days

  • Expected correlated response

Milk trend x.38 correlation = +17 days

reporting of cow fertility
Reporting of Cow Fertility
  • Add mean (such as SCS, calving difficulty)?
  • Reverse scale so positive is desirable?
  • Possible names and abbreviations
    • PTA DO Days Open
    • PTA DPDate Pregnant or

Daughter Pregnancy

    • PTA CFCow Fertility
  • Report preliminary August 2002 rankings?
conclusions
Conclusions
  • Date pregnant has low heritability (~4%) but high genetic correlation with Productive Life (>.5)
  • May 2002 test successful, November 2002 official evaluations possible
  • Indirect selection on PL has reduced decline in fertility, but direct selection could increase lifetime profit.
  • Productive Life preferred over Lifespan
acknowledgments
Acknowledgments
  • Fertility data for the proposed USDA evaluation were prepared by Ashley Sanders
  • Statistical and graphical analysis of results were provided by Mel Tooker