Status
as of: May 1, 2007
Form GE
DESCRIPTION OF NATIONAL GENETIC EVALUATION SYSTEMS
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Country (or countries) |
United States of America |
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Main trait group1 |
Female Fertility - Daughter Pregnancy Rate |
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Breed(s) |
Holstein, Jersey, Brown Swiss, Guernsey, Ayrshire, Milking Shorthorn All breeds and crossbred cows are evaluated together in a multi-breed animal model |
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Trait definition(s) and unit(s) of measurement2 |
Daughter Pregnancy Rate is defined as the percentage of nonpregnant cows that become pregnant during each 21-day period. A DPR of ‘1’ implies that daughters from this bull are 1% more likely to become pregnant during that estrus cycle than a bull with an evaluation of zero. Each increase of 1% in PTA DPR equals a decrease of 4 days in PTA days open |
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Method of measuring and collecting data |
Collected by Dairy Herd Improvement Associations using ICAR approved methods. |
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Time period for data inclusion |
1960 and later for first calving. |
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Age groups (e.g. parities) included |
First five parities are included. |
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Other criteria (data edits) for inclusion of records |
Records for pregnancy rate are considered to be complete at 250 days in milk (DIM), and pregnancy status after 250 DIM is used, but records are set to the maximum 250 DO. Date pregnant is set equal to 50 for any cows that become pregnant before 50 DIM. Some extremely early pregnancy dates obtained by calculation from date of next calving are inaccurate because of short gestation lengths or unreported abortions. The lower and upper limits of 50 and 250 are applied after adjusting days open for season effects and affect 5% and 14% of the records respectively. |
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Criteria for extension of records (if applicable) |
DIM >= 130 days and < 250 days are predicted. |
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Sire categories |
All sires (AI and natural service) are evaluated together. |
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Environmental effects3, pre-adjustments |
Season adjustments based on month fresh, heterogeneous variance adjustments using the same procedures developed for yield traits. Base variance is variance of first lactations for cows calving in 1997. |
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Method (model) of genetic evaluation3 |
ST BLUP repeatability animal model. |
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Environmental effects3 in the genetic evaluation model |
Fixed: management group (flexible herd-year-seasons), parity x age, regression on inbreeding, Random: permanent environment, and herd by sire interaction. HOL management group definition includes registry status. Published PTA includes the expected future inbreeding (EFI) and coefficients of heterosis when mated to purebreds multiplied by the regression coefficients as a post-processing step. |
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Adjustment for heterogeneous variance in evaluation model |
ME, 305 days, twice daily milking, variance of first lactation yield in 1992. Base age varies by breed from 61 to 86 months. |
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Use of genetic groups and relationships |
Unknown parents are grouped by year, breed, and, for Holsteins, separately for U.S. and foreign animals. Unknown sires and dams of cows are grouped separately, but unknown parents of bulls are in a combined group. Separate unknown parent groups are used for red and white or black and white Holsteins. The relationship matrix accounts for effects of inbreeding on Mendelian sampling variance. |
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Blending of foreign/Interbull information in evaluation |
NA |
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Genetic parameters in the evaluation |
Heritability 4%, permanent environment variance 12%, herd by sire interaction 4%, repeatability 20% |
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System validation |
Means and SD for all variables are calculated and examined overall. Means for new bulls, changes for high bulls, largest changes, and key statistics for recent AI bulls are checked. Genetic trends for each breed are validated by methods 1, 2, and 3. |
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Expression of genetic evaluations |
PTA DPR % All-breed PTAs are adjusted to within-breed bases as follows: within-breed PTA = (all-breed PTA – breed mean) * (breed SD / Holstein SD) |
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Definition of genetic reference base Next base change |
Average of all cows born in 2000. February 2010 when the base will be cows born in 2005. |
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Calculation of reliability |
Daughter equivalents from progeny, parents and own records are combined using the same methods as for yield traits. Currently verified and non-verified records receive the same weight. |
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Criteria for official publication of evaluations |
At least 10 daughters with usable fertility data. |
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Number of evaluations / publications per year |
Three, in February, May, and August of 2007, and in January, April, and August beginning 2008. |
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Use in total merit index4 |
Net Merit (all breeds): DPR receives 9% of the total emphasis. In TPI (Holsteins): DPR receives 5% of the total emphasis. |
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Anticipated changes in the near future |
Additional genetic evaluations for days from calving to first insemination and for cow conception rate. |
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Key reference on methodology applied |
· Kuhn, M.T., and P.M. VanRaden. 2004. Use of early lactation days open records for genetic evaluation of cow fertility. J. Dairy Sci. 87:2277. · VanRaden, P.M., A.H. Sanders, M.E. Tooker, R.H. Miller, and H.D. Norman. 2002. Daughter pregnancy rate evaluation of cow fertility. AIPL Research Report DPR1(11-02). Online: http://aipl.arsusda.gov/reference/fertility/DPR_rpt.htm. · VanRaden, P.M., A.H. Sanders, M.E. Tooker, R.H. Miller, H.D. Norman, M.T. Kuhn, and G.R. Wiggans. 2004. Development of a national genetic evaluation for cow fertility. Dairy Sci. 87:2285. · VanRaden, P.M., M.E. Tooker, J.B. Cole, G.R. Wiggans, and J.H. Megonigal, Jr. 2007. Genetic evaluations for mixed-breed populations. J. Dairy Sci. 90:2434. · VanRaden, P.M., and G.R. Wiggans. 1991. Derivation, calculation, and use of national animal model information. J. Dairy Sci. 74:2737. · Wiggans, G.R., and R.C. Goodling. 2005. Accounting for pregnancy diagnosis in predicting days open. J. Dairy Sci. 88:1873. · Wiggans, G.R., and P.M. VanRaden. 1991. Method and effect of adjustment for heterogeneous variance. J. Dairy Sci. 74:4350. |
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Key organisation: name, address, phone, fax, e-mail, web site |
Animal Improvement Programs
Laboratory |
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1) Either: Production (e.g. milk, fat, protein), Conformation, Health (e.g. mastitis resistance, milk somatic cell, resistance to diseases other than mastitis), Longevity, Calving (e.g. stillbirth, calving ease), Female fertility (e.g. non-return rate, interval between reproductive events, number of AI’s, heat strength), Workability (e.g. milking speed, temperament), Beef production, Efficiency (e.g. body weight, energy balance, body conditioning score), or Other traits.
2) Indicate frequencies per category if the trait is categorical and specify transformation of data if practiced.
3) Use abbreviations for most common effects (see document with list of abbreviations at http://www-interbull.slu.se/service_documentation/General/list_of_abbreviations.rtf) and indicate random (R) or fixed (F).
4) Please give economic weights and indicate how they are expressed (preferably in genetic standard deviation units).
Form GE Appendix FF
Parameters for national genetic evaluations for female fertility traits as provided to Interbull
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Country (or countries): |
USA |
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Main trait group: |
Female fertility |
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Breed(s): |
Holstein, Jersey, Brown Swiss, Guernsey, Ayrshire, Milking Shorthorn |
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Trait name |
h2 |
genetic variance |
official proof standardisation formulaa |
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Maiden heifer’s ability to conceive: |
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Lactating cow’s ability to start cycling: |
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Lactating cow’s ability to conceive 1: |
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Lactating cow’s ability to conceive 2: |
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Lactating cow’s interval calving-conception: |
0.04 |
(3.04)2 |
Conversions from the all-breed base to the within-breed bases will be updated on the AIPL web site. March 2007 formulas were: BSW PTA = (all-breed PTA – 0.4)*.990 GUE PTA = (all-breed PTA – 0.4)*.973 HOL PTA = (all-breed PTA + 0.2)*1.000 JER PTA = (all-breed PTA – 2.6)*.939 MSH PTA = (all-breed PTA – 2.3)*.903 RDC PTA = (all-breed PTA – 1.1)*.945 |
a Expressed as follows:
StandEval=((eval-a)/b)*c+d where a=mean of the base adjustment, b=standard
deviation of the base, c=standard deviation of expression (include sign if
scale is reversed), and d=base of expression.
Genetic and residual covariances for countries with national multiple trait evaluations. Genetic covariances on upper diagonals, residual covariances on lower diagonals.
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Trait name |
Trait 1: |
Trait 2: |
Trait 3: |
Trait 4: |
Trait 5: |
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Trait 1: Maiden heifer’s ability to conceive |
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Trait 2: Lactating cow’s ability to start cycling |
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Trait 3: Lactating cow’s ability to conceive 1 |
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Trait 4: Lactating cow’s ability to conceive 2 |
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Trait 5: : Lactating cow’s interval calving-conception |
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