1. Correlations Among Measures of Dairy Cattle Fertility and Longevity

2. Longevity & Fertility Investigation
1,062,791 cows born
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

3. Longevity Parameter Estimates Multi-trait REML Analysis
ProductiveLife
Lifespan
Heritabilities
New Estimates
7.6%
6.7%
Official since 1994
8.5%
Genetic correlations
Lifespan with PL
.986
Protein
.06
.15
SCS
- .31
- .28
Days Open
- .59
- .46

4. Cow Fertility Data Multi-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

5. Fertility Parameter Estimates Multi-trait REML Analysis
Heritability of DO
3.7%
Correlations with DO
Phenotypic
Genetic
Milk
.11
.38
Fat
.09
.33
Protein
.10
.32
SCS
.05
.30

6. 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
Calving interval – 280 days if no reported DO
Exclude most recent 18 months
Assigned DO = 250 if sold for infertility

7. Distribution of Days Open Holstein Calvings 1990 - 2001
Cows culled for reproductive reasons
≤ 50
≥ 250

8. Holstein Phenotypic Trend
Lactation
5th
4th
3rd
2nd
1st

9. 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%

10. Evaluation Test Run Holstein data from May 2002 evaluation
36 million lactations
14 million cows
Statistics for recent, well-sampled bulls
Born
Milk REL > 80% (mean = 87%)
4215 Holstein bulls
314 Jersey bulls

11. Bull Evaluations Holstein Jersey Days Open PTA range -11 to +19
REL mean
59%
57%
PTA correlations PL
-.46
-.23
SCS
.13
-.03
Milk
.22
Fat
.18
.35
Protein
.16
.17

12. Days Open Trends Phenotypic trend 1960 - 1998
Holstein: +37 days
Jersey: +20 days
Genetic trend
Holstein: +17 days
Jersey: +9 days
Expected correlated response
Milk trend x .38 correlation = +17 days

13. 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 DP Date Pregnant or
Daughter Pregnancy
PTA CF Cow Fertility
Report preliminary August 2002 rankings?

14. 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

15. Acknowledgments
Fertility data for the proposed USDA evaluation were prepared by Ashley Sanders
Statistical and graphical analysis of results were provided by Mel Tooker