Introduced in 2003 and updated in 2026, Daughter Pregnancy Rate PTA predicts the expected percentage of non-pregnant cows that will become pregnant in each 21-day cycle, relative to the breed base. The 2026 revision changes the voluntary waiting period (VWP) used in the calculation of DPR from a fixed 50-day VWP with a 20-day grace period to herd-level and lactation group-specific values.
DPR PTA predicts the expected percentage of non-pregnant cows that will become pregnant in each 21-day cycle, relative to the breed base. It is calculated as a function of days open and VWP. Days open (days from calving to confirmed pregnancy) is transformed into a non-linear pregnancy rate with variable VWP by herd-year and lactation group (first lactation only or later lactations) as:
Evaluations are expressed in percentages.
For example, daughters of a bull with a DPR PTA of +1 are expected to have an average pregnancy rate 1% higher than the breed base (mean). The following breed means were calculated using data from the December 2025 evaluation and may vary slightly as more phenotypic data is added.
| Breed | Breed Mean |
| Ayrshire | 25.29% |
| Brown Swiss | 24.55% |
| Guernsey | 23.44% |
| Holstein | 32.19% |
| Jersey | 34.98% |
| Milking Shorthorn | 28.62% |
Evaluations for DPR are provided for Ayrshire, Brown Swiss, Guernsey, Holstein, Jersey, and Milking Shorthorn (traditional only) males and females.
DPR has been included in the lifetime merit indexes since 2003. As of the April 2025 update to the indexes, DPR has the following relative emphasis in each:
These values represent DPR’s economic importance to reproductive efficiency and herd profitability. The August 2026 modifications to DPR do not affect these emphases because the weights on traits in the lifetime merit indexes are based on economic values that are not being updated. Animal variations in NM$, CM$, FM$, and GM$ that are expected with the updates to DPR will be due to changes in PTA values because of the reformulation, not the relative emphasis of the trait in the index.
DPR has a heritability of 2.9%. This level is typical for reproductive performance traits, indicating that genetic progress is gradual but cumulative over time.
Reliability varies by animal and is influenced by the amount of available information. Young animals typically have lower reliability, while proven sires with extensive daughter records have higher reliability.
| Breed | Active A.I. Bulls Reliability |
| Ayrshire | 34% to 98% |
| Brown Swiss | 63% to 99% |
| Guernsey | 38.5% to 93% |
| Holstein | 32.5% to 99% |
| Jersey | 58.8% to 99% |
| Milking Shorthorn | 52.9% to 89.8% |
Within the reproductive performance trait portfolio, DPR is strongly correlated with Cow Conception Rate (+0.94) and First Service to Conception (+0.96) and moderately correlated with Heifer Conception Rate (+0.56).
These correlations allow information from related reproductive performance traits to improve evaluation accuracy, particularly when data is limited.
The data used to calculate this trait is stored in the National Cooperator Database. DPR utilizes reproductive and calving records, including insemination, pregnancy diagnosis, and calving information reported through U.S. dairy records programs.
Most animals fall within a relatively narrow range around zero, with positive PTA indicating higher-than-average genetic potential for pregnancy rate and negative PTA indicating lower-than-average genetic potential relative to the breed base. Approximately 68% and 95% of observations fall within one and two standard deviations (SD) of the mean, respectively.
Graham, J.R., VanRaden, P.M., McWhorter, T.M., et al. Development of a first-service-based fertility trait for U.S. dairy cattle. (In preparation).
Kuhn, M.T., VanRaden, P.M., and Hutchison, J.L. Use of early lactation days open records for genetic evaluation of cow fertility. J. Dairy Sci. 87(7):2277–2284. 2004.
McWhorter, T.M. et al. (2025). Foundational Review of U.S. Trait Evaluations. Interbull Bulletin.
VanRaden, P.M., Sanders, A.H., Tooker, M.E., Miller, R.H., and Norman, H.D. (2004). Development of a national genetic evaluation for cow fertility. Journal of Dairy Science.
VanRaden, P.M., Tooker, M.E., Wright, J.R., Sun, C., and Hutchison, J.L. Comparison of single-trait to multi-trait national evaluations for yield, health, and fertility. J. Dairy Sci. 97(12):7952-7962. 2014.
VanRaden, P.M., Sanders, A.H., Tooker, M.E., Miller, R.H., and Norman, H.D. Daughter pregnancy rate evaluation of cow fertility USDA AIPPL RESEARCH REPORT DPR1 (11-02).
VanRaden, P.M., Sanders, A., Tooker, M., Miller, R., and Norman., H. Daughter Pregnancy Rate Evaluation of Cow Fertility. AIPL Research Report. Government Publication.
Wiggans, G.R., and Goodling, R.C. (2005). Accounting for pregnancy diagnosis in predicting days open. Journal of Dairy Science.
Information last updated May 1, 2026.
