Pregnancy Testing By Will Winter, DVM

When I first entered the field of veterinary medicine only one method ruled the day: manual rectal palpation of the uterus through the wall of the large intestine.

Rectal palpation is a delicate task requiring soft fingertips, “eyeballs” the professors called them.

Rectal palpation risks accidentally killing and/or aborting the fetus.

This risk varies with the skill level of the tester but fetal injuries can add 1-5% to the “opens.” This is one of the main reasons why a few cows who test “pregnant” may come back into heat two to four weeks post-testing, assuming no additional damage.

Soon after graduation I think I developed those “eyeballs” on the ends of my fingertips and became competent at pregnancy testing as well as learned how to check both ovaries for cysts (bad), follicles (good) or corpora lutea (C.L. the essential pregnancy indicator). In testing “open” females, if we happen upon a cystic ovary it’s not difficult to “pop” it thus allowing the reproductive tract to get active again. This is still a great technique for correcting sterile cows (sometimes) and I recommend all “open” cows be palpated. Follicles and C.L.s should never be handled roughly. This form of palpation will also detect pelvic anomalies or other anatomical problems that could cause dystocia or calving problems later. No other test does this.

Rectal palpation requires putting the animals in a squeeze chute, occasionally with a head gate, which can lead to considerable stress. This is something that could also cause a cow to abort, just from that stress (and some pain). And although I’ve never been seriously injured after performing thousands of these tests, that too is a risk for the technician.

No longer my favorite system, rectal palpation is still by far the most common method used. It’s fast, offers an immediate diagnosis, and costs only $4-12 per test. A good technician can detect pregnancy as early as 30 days, necessitating good breeding records and a marking I.D. system for each animal.

HIGH TECH TESTING

Method #2 is the use of Ultrasonography or the latest version Doppler Ultrasonography. Both are referred to as ultrasound. Like all the methods, accuracy often depends on the experience and techniques of the tester. The more advanced Doppler version is in color and gives an accurate assessment of blood flow, even the heart beat of the fetus. The tester can also measure blood flow to the ovaries including the C.L. Accuracy of diagnosis is limited to testing after day 25 of pregnancy although the function of the C.L. can be evaluated as early as 19-21 days pregnant. With a good tester, results approach 98.5% accuracy. It will determine the age of the developing fetus and in some cases the gender. Ultrasound usually costs about twice as much per test as rectal palpation. Both tests give immediate results.

AN EASY TEST

The 3rd and newest method of preg testing involves a simple blood chemical analysis. Only one to two drops will do, usually taken with a tiny and painless puncture at the base of the tail. It’s fast, inexpensive ($4-6) and, unlike the other two methods, doesn’t require an experienced technician.

Accuracy varies from version to version depending upon which chemical is tested. Some are totally pregnancy-dependent whereas other chemicals (even though they are hormones as well) can come from other sources and give a false positive. The results take several days to get back. One of the most common chemicals tested is for Pregnancy Associated Glycoproteins (PAGs). Testing can begin as early as 28 days post-breeding. No one has settled on which test is best, PAG, ELISA, RIA or others but the newest test for MicroRNA shows promise for accuracy. Most of these tests can be used accurately for horses and sheep as well.

If you are in the cattle business very long it’s quite easy to see that the results of all forms of preg checking leave room for doubt. Who hasn’t seen a “surprise” calf pop up in a herd of purchased stockers? The flip side and more expensive surprise is when a supposed bred animal comes up open.

CONCLUSION

All of these tests have value and almost all livestock producers are advised to get an excellent handle on the status quo for pregnancy status, as well as overall health and fertility levels. Accurate testing will enable the smart producer to deal with open cows and heifers as soon as possible, reducing financial risk.

Now for the fourth method, opti- mal herd health and no pregnancy checking at all. This isn’t for every- one since it’s viable only to people who have already created a top- notch herd! This method is viable when herd health and fertility issues have been mastered and the concep- tion rate approaches 100% positive. With a holistic health plan in place, many herds attain this reproductive benchmark. When that level of fertility occurs, pregnancy checking is virtually obsolete.

The four basic concepts of holistic health include selective genetics for the kind of cattle that have high levels of health and fertility (including the bulls), nutrient-dense, high Brix forages or stored forages year- round, a sustainable and regenerative program of rotational grazing and, lastly, high-quality supplements given free-choice to insure maximum immunity and health. Typically, these include an all-in-one vitamin/mineral mix, free-choice natural salt, detox options such as baking soda, montmorillinite clay, and Apple Cider Vinegar free-choice or in the feed or water.

Managers should protect the herd from all forms of detrimental pollution such as excessive EMF radiation, heavy metals, pesticides, herbicides and insecticides and other harmful drugs such as vaccines, chemical wormers and antibiotics.

A herd that no longer requires pregnancy testing to assure a great calf crop is at the pinnacle of profitable production.

Standard Disclaimer: The theories and comments presented in this message are expressed as the author’s opinion. They are based on personal experience and long-term research studies. as such they are not meant to be used to diagnose, prescribe, or to administer in any manner to any physical ailments. In any matter related to individual cases please contact a qualified, licensed veterinarian.

Will Winter, DVM is a holistic herd health consultant and livestock nutritionist. He resides in Minnesota and lectures and teaches across the USA. He can be reached at willwin- [email protected] or willwinter. com.