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Pregnancy in dairy cows is detected using rectal palpation, ultra sound examination and laboratory-based hormone tests.

Pregnancy diagnosis

Many critical farm business management decision revolve around knowing when a cow will calve. 

Developing a pregnancy testing strategy that fits your calving pattern and business can help to:

Measure and monitor herd reproductive performance

Pregnancy testing enables you to accurately measure and monitor herd reproductive performance.

  • 100-day in-calf rate and 200-day not-in-calf rate in year-round calving herds (InCalf book, Year-round calving measures, page 17-18)
  • 6-week in-calf rate and not-in-calf rate in seasonal and split calving herds (InCalf book, Seasonal/split calving measures, page 18-19).

Timely pregnancy testing also allows you to calculate the conception rate – a driver of in-calf rates.

Improve record keeping data

Keeping good data combined with regular analysis is the basis of a fertility management plan.

The minimum records for good monitoring are animal birth dates, calving dates, mating dates and pregnancy test results. With this data, you can:

  • calculate the reproductive performance of your herd or of groups within the herd such as heifers
  • look for patterns among empty cows. Were they late calvers? Treated as non-cyclers? Mainly heifers or first calvers?
  • see more clearly the effectiveness of individual parts of reproductive management on performance
  • examine the impact of heat detection, AI, calving pattern etc. on overall herd performance, and
  • predict future calving and milk production allowing better budgeting of finances and feed.

Inform decisions on individual cows

Pregnancy testing with foetal aging is required for you to determine cow conception dates with confidence and is an essential component of a herd’s effective pregnancy testing strategy.

Effective and complete pregnancy testing data helps you to:

  • confidently re-breed or cull cows as non-pregnant
  • provide approximate due-to-calve dates if selling cows
  • confidently dry-off cows at your preferred time before their due- to-calve date, providing longer lactations, more milk income
  • more accurately draft springing heifers and dry cows into transition cow groups so they receive the transition diet for the optimal 3 weeks prior to calving and minimise transition diet costs, and
  • know the sire of the calf - this helps you manage the genetics of the herd and avoid inbreeding.

Pregnancy testing with foetal aging helps you to predict the next calving date. Use this information to schedule the dry-off dates for individual cows that provide a 60 day dry period.

With this information and scheduling you can milk each cow based on her own individual dry-off date.

Compared to using a blanket dry-off date, individual dry-off scheduling may assist in producing extra milk, minimising transition cow feeding costs and generating more profit.

Pregnancy testing based on your calving pattern

Year-round calving herds

Pregnancy testing enables you to:

  • focus extra heat detection efforts on non-pregnant cows
  • use heat synchrony to induce heats in non-pregnant cows
  • more accurately predict milking herd size for the coming 6 months.

Seasonal/split calving herds

Pregnancy testing enables you to:

  • differentiate AI from natural mating pregnancies
  • identify the sire of the AI pregnancy based on conception date
  • identify cows that become pregnant in the last few weeks of mating.

Foetal aging is currently only possible using manual rectal pregnancy testing by an experienced operator and is most reliable when cows are between 5 and 15 weeks pregnant.

Our information and case studies describe the range of laboratory tests for pregnancy diagnosis in dairy cows that are commercially available in Australia and demonstrate how dairy farmers have used laboratory tests and their experiences with this technology.

For further information, read the InCalf book 2nd edition, Section D pages 159-172.

Laboratory Tests for Pregnancy Diagnosis in Dairy Cows

Reliable methods for detecting early pregnancy in dairy cows include rectal palpation, ultra sound examination and laboratory-based tests that target proteins or hormones that become elevated in blood and/or milk during pregnancy.

For more information on pregnancy diagnosis in dairy cows, download this fact sheet.

Fact sheet: laboratory tests for pregnancy diagnosis in dairy cows (PDF, 1.5MB)

Describing all commercially available Australian lab tests for pregnancy diagnosis in dairy cows. Contact details of the major suppliers of the tests, and the pros and cons of laboratory testing, is included.

Case Studies

Learn how other dairy farmers have used laboratory tests for diagnosing pregnancy in their cows, and their experiences with this technology.

Greg Rogers, Katunga, Victoria

Case Study: Greg Rogers: Laboratory tests for pregnancy diagnosis in dairy cows (PDF, 2MB)
Greg milks 260 cows, mainly Friesians with a few Jerseys at Katunga in northern Victoria.

Pam Malcolm, Invergordon, Victoria

Case Study: Pam Malcolm: Laboratory tests for pregnancy diagnosis in dairy cows (PDF, 552KB)
Pam Malcolm has been running Paringa Holsteins, in northern Victoria, since 1982. She milks 200 cows in a split-calving system.


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