Signs of Heifer Pregnancy

Typically, farm heifers become pregnant in one of two ways: by artificial insemination or by being "serviced" by a bull. It is then essential that the heifer's condition (pregnant or not pregnant) be determined. If she is pregnant, she will need special feed and care, and, obviously, it would be dangerous for her to be inseminated or serviced again. There are several methods available to help determine pregnancy in a heifer, some more accurate than others.

  1. Non-Return To Oestrus

    • Typically, if oestrus (period of fertility) is not observed 3 weeks after insemination or service, the heifer is considered to be pregnant. However, 7% of heifers will show signs of oestrus during pregnancy, so this is not the most reliable method for determining pregnancy.

    Rectal Palpation

    • Rectal palpation--the manipulation and examination of the bovine reproductive tract--is considered the fastest, most inexpensive and safest way to determine pregnancy. If done by a skilled practitioner, rectal palpation is 95 percent accurate.

    Hormone Measurement

    • 18 to 24 days following insemination or service, progesterone secreted by the corpus luteum can be assayed to determine pregnancy. However, a study by Pierce et al. (1989) indicated that the accuracy of this test is quite low.

    Early Pregnancy-Associated Protein

    • This blood test detects pregnancy-associated glycoprotein, a so-called early conception factor (ECF). However, because this test is typically done within 48 hours of insemination or service, it should only be used to detect conception. A more reliable pregnancy test should be taken later.

    Ultrasound

    • Determining pregnancy via ultrasound is gaining popularity. In the hands of a skilled practitioner, ultrasound is safe, simple and has a 99 percent rate of accuracy.