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Pregnancy Testing

Submission Guidelines

Submission Form (PDF)

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Pregnancy Testing

  • Confirm pregnancy through pregnancy specific proteins (PAG). PAGs are released by the placenta during pregnancy and are specific to pregnancy unlike some other chemical indicators, such as progesterone.
  • Results comparable to traditional methods.
  • 98% Accurate (98.8% Sensitivity, 97.4% specificity); comparable to palpation and ultrasound.

Sample Types

When To Use

  • Test as early as 28 days post-breeding through dry-off.
  • Must be at least 60 days post-calving.

Testing Strategies

  • The first pregnancy check should be performed 28-40 days carried calf (DCC). This allows for timely rebreeding if she is determined to be open.
  • Subsequent pregnancy checks after an initial diagnosis of ‘pregnant’ are recommended to ensure pregnancy is maintained. Second checks typically occur 55-75 DCC. During this time period, fetal mortality risk is high and there is a higher chance of a recheck result on milk samples. A third check is often performed at 90-120 DCC. This is past the highest pregnancy loss risk, so another good time to verify pregnancy has been maintained. Lastly, a “dry check” is often performed around 200-220 DCC. This is the final check to ensure the cow is still pregnant before taking the steps to dry her off so she can prepare for calving and her next lactation.

Results interpretation

Results reported as pregnant, open and recheck based on the levels of PAGs present.

Pregnant

PAGs were detected

Next Step Perform confirmatory tests based on days carried calf as mentioned in testing strategy section
Open

PAGs were not detected

Next Step Eligible for rebreeding
Recheck

PAGs were detected, but not at a level strong enough to diagnose a pregnancy.

Next Step Confirm pregnancy status with a new sample or veterinary palpation
Test Type Pregnant Open Recheck
Milk ELISA >0.25 <0.10 0.10 – 0.25
Blood ELISA >0.30 <0.30  

Submit Samples

Additional Information

Testing Supplies

FAQs

How does milk or blood pregnancy testing work in cattle, sheep, and goats?
Pregnancy testing using milk or blood samples detects pregnancy-associated glycoproteins (PAGs) released by the placenta during pregnancy. Unlike progesterone-based tests, PAG testing is specific to pregnancy and delivers results comparable to ultrasound or palpation, with 98% accuracy.
When can I test my cows for pregnancy?
You can test as early as 28 days post-breeding and continue testing through dry-off, provided the animal is at least 60 days post-calving. Early testing allows for timely rebreeding if the cow is open, improving herd fertility and efficiency.
How often should pregnancy testing be done?

A strategic testing schedule helps confirm and maintain pregnancy:

  • First check: 28–40 days carried calf (DCC) to detect open cows early.
  • Second check: 55–75 DCC to confirm ongoing pregnancy.
  • Third check: 90–120 DCC to verify pregnancy past the high-risk loss period.
  • Dry check: 200–220 DCC to ensure pregnancy before dry-off.
How are pregnancy test results interpreted?

Results are available within 24 hours of sample receipt.

  • Pregnant: PAGs detected
    • Confirm with follow-up test per DCC guidelines.
  • Open: PAGs not detected
    • Cow is eligible for rebreeding.
  • Recheck: Borderline PAG levels
    • Retest or confirm with veterinary palpation.
Where can I send samples for milk or blood pregnancy testing?

Send samples directly to the CentralStar laboratory or contact your DHI Specialist for assistance. Both fresh and preserved milk, as well as fresh serum and plasma samples, are accepted. Testing supplies, shippers, and collection tubes can be conveniently purchased online.

CentralStar’s laboratories provide sample analyses on milk, blood, fecal, and tissue samples for a variety of production, disease and health-related traits. More than 6 million samples are processed annually using state-of-the-art equipment and techniques including infrared spectroscopy, flow cytometry, ELISA, PCR, and more.

CentralStar laboratory services are intended solely for the detection of specific microorganisms or viruses in approved sample types. These services do not evaluate, certify, or guarantee the safety of milk for human consumption. It is recommended that interpretation of the results provided, and management decisions based on these results be done under the advisement of a veterinarian.