Herd Management: Pregnancy Checking
One important herd management practice that often gets overlooked or neglected by beef cattle producers is pregnancy examinations.
According to 2007-08 National Animal Health Monitoring System data, only about twenty percent of beef cow-calf producers use pregnancy testing or palpation in their herds.
The most obvious benefit of knowing which cows are open is cost savings. A pregnancy examination will typically average $5 per head but carrying an open cow over the winter may cost several hundred dollars in hay alone. Not to mention mineral, supplemental feed, vaccines, and de-wormers that adds additional carrying costs.
Beyond the marketing aspects, pregnancy checking can be a tremendous decision making tool. Cows can be grouped into herds as having early or late births in the calving season. This way the females can be fed accordingly.
Scours vaccine can also be administered at the right time to optimize colostral antibodies for the calf.
Pregnancy exams are also important for the measurement of herd health and reproductive status. More open cows than expected may indicate an abortion problem caused by the IBR or BVD viruses. It could also be an indicator of a sexually transmissible disease such as vibriosis or trichomoniasis.
Nutritional deficiencies including a lack of energy, trace minerals, and/or protein may delay estrus and conception due to poor egg development and subsequent ovulation, resulting in open cows.
Occasionally, cows that will not breed back may have had damage to the reproductive tract due to a difficult birth.
Infertile bulls may be discovered at pregnancy checking time when too many cows are returning to heat. Hopefully, this would be noticed before the end of the breeding season. Bulls should have a breeding soundness examination prior to breeding season for this reason.
Pregnancy examinations can be accomplished by several different methods including rectal palpation, ultrasound or a blood test.
Rectal palpation performed by an experienced veterinarian can estimate the approximate stage of pregnancy and can be detected 35-40 days after breeding. Veterinarian use the palpation of fetal membranes, position of the uterus, size of the cotyledons and size/strength of pulse in the uterine arteries to determine pregnancy status and length of gestation.
Many cow-calf producers have taken to palpating their own cows to cut veterinarian costs.
- The following are the stages of pregnancy that are detected by palpation.
70 days – The enlarging uterus is readily felt. The amnion sac feels like a solid oval ball (about 2¼ in. in diameter) floating within it.
- 90 days – The uterus is usually still resting up near the pelvic brim, with the pregnant horn about 3½ in. wide and the non-pregnant horn about 2 in. wide. The fetus can sometimes be felt in the pregnant horn.
- 110 days (3½ months) – The enlarging uterus has dropped below the pelvic brim (the cervix lies at the brim) and there is fluid distention in the lower part of the uterus.
- 4-5½ months – It is possible to feel the fetus in about half the cases.
- 5½-7½ months – It’s more difficult to reach the uterus, but if so, you may be able to touch the fetus’ head or flexed limbs that lie just beyond the pelvic brim.
7½ months to birth – It’s often easier to feel the fetus because it’s grown so much that the front legs are closer to the pelvis. If you can’t reach the uterus, you may be able to feel large cotyledons or a strong vibrating pulse in the enlarged uterine arteries.
Disadvantages to palpation are few and often exaggerated. Rough handling of the fetus or membranes early in gestation has been associated with abortion but it is difficult to differentiate these from the “normal” amount of expected embryonic loss.
Another concern is blood borne diseases such as anaplasmosis and bovine leukemia virus that can be transmitted cow-to-cow by blood present on an examination sleeve used in multiple cows.
An ultrasound can detect pregnancy earlier than palpation but is more expensive, largely due to the cost of the equipment. It can provide more detailed information such as viability of the fetus, presence of twins and sex of the calf and it is considered extremely accurate.
Both ultrasound and palpation provide immediate answers as to being pregnant or open, so cows can be sorted from the chute without being handling multiple times.
With a blood test, heifers and cows can be tested at 30 days or later after breeding but a cow must be at least 90 days post calving due to residual protein from the previous pregnancy. The blood must be drawn and sent to a participating laboratory for results so cows would need to be sorted at a later date after results were reported.
A blood test is advertised as ninety-nine percent accurate when it identifies open cows at least 30 days post breeding with less than one percent showing false-open. Being correct with an open detection is very important because giving prostaglandin to a pregnant cow will cause an abortion. The false-pregnant rate for the test is approximately five percent.
In a year such as this, where hay prices are high and cattle prices are as well, producers need to save as much as they can on costs and sell off those unproductive cows as soon as possible.
Getting the female herd checked for pregnancy, by means of whichever the producer chooses, is an essential herd management tool that will ultimately pay off every season for every cow-calf producer.
Callie McCullough is a junior at Texas A&M University pursuing a dual degree in animal science and agricultural communications. She’s a fifth generation rancher from Ridge, Texas. Born and raised on the family cow-calf operation, she is an avid cattle enthusiast and has a passion for the production cattle industry and its future.