Individual Traits / Genetic Evaluations / Services / Cow Conception Rate

Cow Conception Rate (CCR)

Available for all breeds, CCR predicts a lactating cow’s ability to conceive and is expressed as a percentage.

Benefits of Trait

Introduced in 2009 and updated in 2026, Cow Conception Rate PTA predicts the expected difference in conception rate of daughters as lactating cows relative to the breed base. The 2026 revision adds a days-in-milk covariable to the model.

  • Improves genetic selection for successful conception in lactating cows
  • Supports reduced breeding costs and fewer inseminations per pregnancy
  • Enhances reproductive efficiency in modern herd management systems
  • Complements Daughter Pregnancy Rate by focusing on conception success rather than time to pregnancy
Trait – CCRDownload

Cow Conception Rate Trait

Cow Conception Rate is defined as the proportion of inseminations that result in pregnancy for an individual cow, based on outcomes for up to the first seven inseminations. CCR PTA predicts the expected difference in conception rate of an animal’s daughters as lactating cows relative to the breed base.

CCR is calculated using up to seven inseminations (0 for failure; 1 for success) within a lactation. These inseminations are adjusted for mating type, service sire breed, and short cycling, then used to calculate a conception rate by dividing by the total number of inseminations required.

Evaluations are expressed in percentages.

For example, daughters of a bull with a CCR PTA of +1 are expected to have an average conception rate 1% higher than the breed base (mean).

Evaluations for CCR are provided for Ayrshire, Brown Swiss, Guernsey, Holstein, Jersey, and Milking Shorthorn (traditional only) males and females.

CCR has been included in the lifetime merit indexes since 2014. As of the April 2025 update to the indexes, CCR has the following relative emphasis in each:

  • NM$: 1.8%
  • CM$: 1.7%
  • FM$: 1.8%
  • GM$: 5.2%

These values represent CCR’s economic importance to reproductive efficiency and herd profitability. The August 2026 modifications to CCR 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 CCR will be due to changes in PTA values because of the reformulation, not the relative emphasis of the trait in the index.

CCR 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.

BreedActive A.I. Bulls Reliability
Ayrshire32% to 98.1%
Brown Swiss60% to 99%
Guernsey37.3% to 93%
Holstein31.5% to 99%
Jersey58.1% to 99%
Milking Shorthorn51.9% to 89.2%

Within the reproductive performance trait portfolio, CCR is strongly correlated with First Service to Conception (+0.98) and Daughter Pregnancy Rate (+0.94) and moderately correlated with Heifer Conception Rate (+0.52).

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. CCR utilizes reproductive records, including insemination events, pregnancy diagnoses, and subsequent calving confirmations 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.

Related Publications

Hutchison, J.L., VanRaden, P.M., Norman, H.D., and Cole, J.B. Technical note: Changes to herd cutoff date in conception rate evaluations. J. Dairy Sci. 96(2):1264–1268. 2013.

McWhorter, T.M. et al. (2025). Foundational Review of U.S. Trait Evaluations. Interbull Bulletin.

Miles, A.M., Hutchison, J.L., and VanRaden, P.M. Improving national fertility evaluations by accounting for the rapid rise of embryo transfer in US dairy cattle. J. Dairy Sci. 106(7):4836-4846. 2023.

Norman, H.D., Hutchison, J.L., VanRaden, P.M., and Cole, J.B. (2008). Genetic evaluation of cow conception rate. 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.

Information last updated May 1, 2026.