We do a lot of pregnancy diagnosis at our veterinary clinic and we use several technologies – manual palpation, ultrasound examination, and blood pregnancy diagnosis. By far the most common way we diagnose cows as pregnant is by examining blood samples that producers collect from their cows and send or deliver to us. The reason is simple - testing cattle blood samples for pregnancy is inexpensive, accurate very early in gestation, easy, convenient, and safe.
How do you, as a producer, take advantage of this relatively new technology? First, you need to understand a little about it. The test the lab runs is designed to detect pregnancy specific proteins.
These proteins are produced by the dam’s placenta during gestation. They are produced no earlier than about 22 days gestation, but are reliably present by the end of the 28th full day of gestation. As the pregnancy progresses, these proteins become very numerous. In fact, the proteins will still be detectable in a blood sample as late as 72 days after giving birth to the calf.
The lab needs a 2-3cc sample of blood and it should be collected via needle/syringe and transferred to a red topped tube. Label the tube with the cow or heifers ID – name or tag number. Fill out the submission form to submit with your samples, indicating which test/s you would like to run. Be sure to also check on the form how you would like to receive your results (email, fax, phone, mail). A submission form can be found on the website under the “Testing” tab.
Most producers will tail bleed their animals to obtain the necessary blood sample. This can be a little intimidating if you have never done it before but it does not need to be. Restrain the animal securely, preferably in a head chute. You will need to grab your clean needle and syringe. How you
hold the syringe is key to being able to do this - hold the barrel of the syringe with the first 2 fingers and thumb, use the third finger to pull out the syringe plunger. Hold the tail up at an angle that lets you see the bottom side of the tail and insert the tip of the needle into the middle of the tail (side to side) and one or two vertebrae spaces down the tail from the rectum. Put some vacuum on the plunger of the syringe with your third finger and when blood appears hold still and wait for the syringe to fill. Remove your needle from the tail and insert into a red topped tube. After injecting the blood into the tube make sure that the ID on your tube matches the animal you took the sample from and grab a new needle/syringe for the next animal. Never use the same needle and syringe on two different animals to draw blood without thoroughly cleaning between animals. Failure to do so will spread disease, such as anaplazmosis, and mess with the accuracy of the tested sample.
This blood pregnancy testing technology lets producers check the pregnancy status of their herd very early in gestation with great accuracy. A lot of producers will AI on day 1, put the bull in on day 11, and then pull blood on day 29 or 30 in order to accurately determine AI preg rates. The bull can breed a cow or heifer the minute he walks in the pen and the cow can be pregnant by the bull when drawing the blood sample but the proteins are not present yet on the bull pregnancies. Producers should then pull blood on all the rest of the animals 30 days after you pull the bull out to get your breed up results.
One very useful aspect to this testing protocol is that you can tell if you have a pregnancy wastage problem in your herd. If the animals bred early to AI do not all calve close to the AI due date it may help you to decide that you have a pregnancy wastage problem rather than a pregnancy establishment problem. This kind of knowledge is extremely useful when trying to figure out if you have disease problems in your herd such as BVD, Johne’s, Neospora, etc. Those problems can cost you pregnancies, calves, and money.
If you have questions get in touch with us at 1-800-443-6389 or learn more about this testing method on our website.