| Country (or countries) | United States of America |
| Main trait group | Female Fertility - Daughter Pregnancy Rate |
| Breed(s) | AYS, BSW, GUE, JER, HOL (B&W and R&W), MSH |
| Trait definition(s) and unit(s) of measurement | 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. |
| Method of measuring and collecting data | Collected by Dairy Herd Improvement Associations using ICAR approved methods. |
| Time period for data inclusion | 1960 and later for first calving. |
| Age groups (e.g. parities) included | First five parities are included. |
| 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. |
| Criteria for extension of records (if applicable) | DIM >= 130 days and < 250 days are predicted. |
| Sire categories | All bulls are evaluated together. About 1950 AI and 1885 NS new bulls evaluated each year. |
| Environmental effects, 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. |
| Method (model) of genetic evaluation | ST BLUP repeatability animal model. |
| Environmental effects 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) multiplied by the regression coefficient as a post-processing step. |
| 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. |
| Use of genetic groups and relationships | Unknown parents grouped by birth year. For cows, sires and dams grouped separately; for bulls, sires and dams together. [HOL} Canadian animals grouped separately. |
| Blending of foreign/Interbull information in evaluation | NA |
| Genetic parameters in the evaluation | h2= 0.04, t = 0.11 |
| 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 all breeds are validated by methods 1, 2, and 3. |
| Expression of genetic evaluations If standardised (e.g. RBV), give standardisation formula in the appendix |
PTA |
| Definition of genetic reference baseNext base change | Average of all cows born in 2000.February 2010 when the base will be cows born in 2005. |
| 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. |
| Criteria for official publication of evaluations | At least 10 daughters with usable fertility data. |
| Number of evaluations / publications per year | Four, in February, May, August, and November. |
| Use in total merit index | DPR receives 7% of the total emphasis for NM. |
| Anticipated changes in the near future | Correlated information from other traits will be included in a multi-trait DPR. Foreign bull DPR will be derived using MACE for longevity and other traits instead of just DPR parent average. |
| Key reference on methodology applied |
|
| Key organization: name, address, phone, fax, e-mail, web site | Animal Improvement Programs Laboratory USDA, Agricultural Research Service Building 005, Room 306, BARC-West 10300 Baltimore Avenue Beltsville, Maryland 20705-2350 U.S.A. Tel: 301-504-8334 Fax: 301-504-8092 E-mail: paul@aipl.arsusda.gov web site: http://aipl.arsusda.gov |
Updated: This file last modified 02/28/24