Our pregnancy tests are based on the detection of a panel of pregnancy-associated glycoproteins in the blood. PAGs are a family of proteins that are produced by specialized cells of the developing placenta. These proteins start being produced early in pregnancy, are taken up into the dam’s blood, and can be found in serum. Although the production of these proteins begins early in the period of attachment of the embryo, their concentration is not high enough for detection until day 28-35 of pregnancy, depending on the species. PAG production is maintained at a high level until the termination of pregnancy and residual PAGs can be detected in serum for a period of time after birth.

Normally, if a female is not pregnant following natural service or artificial insemination, she should come back into heat with a normal cycle (cow - 18 to 24 days, sheep - 16 to 18 days, goats - 18 to 24 days). Females that are not observed in heat following a mating are often presumed pregnant. However, heat detection is not always reliable, and certain pathological conditions can interfere with a normal estrous cycle. Testing for PAGs is an extremely reliable method of pregnancy detection that can be used as early as 28 days after mating in cattle and goats, allowing for rebreeding of open females.

We recommend testing 28 days post-breeding for cows and goats and 35 days post-breeding for sheep. In most species, it is expected that a few animals will lose their pregnancy early on. Most of these losses occur in the first 40 days of pregnancy. Therefore, some females may test as pregnant at 30 days and either return to estrus or fail to give birth. It is always prudent to retest animals later in pregnancy to confirm their status. If several females present with this situation (being open following a positive pregnancy test result), it is important to consult with your veterinarian about investigating the underlying problems of pregnancy loss.

If blood samples are taken less than 60 days after giving birth they may test positive, regardless of the current pregnancy status of the animal, due to residual amounts of PAGs from the previous pregnancy. This is why it is important to test no earlier than 60 days after birthing.

If a female tested open and is determined to be pregnant at a later date, the most common reason would be that the female was bred at a later date, or that the sample was taken too early.

If the animal test negative, but is not coming back into heat there is a possibility that the female bred. The chances of this are extremely low but can occur. In these cases, you may choose to retest the animal. However, there are several reasons an open female will not return to estrus. These include ovarian or uterine diseases and seasonality. Consult your veterinarian if any questions arise.

Collect samples at a minimum of 28 days post-breeding in cattle and goats and 35 days post-breeding in sheep.

Obtain 2-3ml of blood in a RED top tube. A purple top tube may be used with cattle only.

Tests are run daily, except on weekends and holidays. Tests can be run the same day while cows are penned by appointment only.

Download a submission form and include it in your shipment with samples and payment.

Bundle tubes together in groups of 2-10 tubes with a rubber band. Wrap the bundle with paper towels, enough to absorb fluid if tubes break. Place samples inside a leak-proof ziploc bag. Repeat as needed depending on the number of samples.

Ice packs are not required for pregnancy testing. Pack the bags with bubble wrap or paper inside a cardboard box. Please do not ship samples in plain or padded envelopes.

Payment is due at the time of service. Accepted forms of payment include checks or credit cards. Please make payment payable to Texas Livestock Lab.

Ship via USPS, UPS, or FedEx. Packages are accepted Monday-Saturday. Never require a signature for delivery. Shipping labels can be printed at home using sites like Pirate Ship. Write “Exempt Animal Specimen” on the exterior of the box.

Ship to:

Texas Livestock Laboratory

827 FM 197

Arthur City, Texas 75411

Drop Off

Packages may be placed in the drop-off box at the lab. Please text 903-495-8931 when you leave a package. Be sure to include payment with your samples. Please text 903-495-8931 for driving directions. GPS will almost always take you to the wrong location!