Pregnancy testing beef cows as early as 30 to 45 days after the end of the breeding season might be a good idea. Gerald Stokka, NDSU Extension veterinarian and livestock stewardship specialist, says ultrasound, palpation and blood tests are all tools that can be used. But each has a unique fit.
1. Ultrasound. Ultrasound can be used at around 30 days post-breeding, Stokka says.
2. Palpation. Palpation can be used one to two weeks later than ultrasound. The experience level of the technician and the method used will determine the earliest date that tests can be conducted, he says.
3. Blood-based pregnancy tests. The test can be used within 60 to 90 days post-calving and 25 to 30 days post-breeding, depending on the type of test used, Stokka says.
Test kits can be purchased from several commercial sources, and the producer can collect blood samples on the ranch.
Most blood samples have to be sent to a certified laboratory for detection of pregnancy-related proteins; however, some blood testing kits that are designed for veterinary practice can be read visually within about 30 minutes with no additional equipment needed. Because the proteins of interest remain in the cow after calving, the previous pregnancy can cause interference if the recommended sampling period is not followed.
Blood-based tests do not require an experienced technician or specialized equipment to collect the samples. However, some kits require additional time for samples to be shipped and processed at a laboratory.
For quick-response blood tests, animals must be put in a holding pen while pregnancy status is determined, and additional sorting may be required. The required interval between calving and blood sampling means that other methods could be used earlier in most cases. In addition, false positives may be seen for several days after a cow has undergone an abortion.
Rectal palpation and ultrasound can determine pregnancy immediately without extra handling. Additionally, these methods can be used to determine the age of the fetus and monitor reproductive organs, while blood tests cannot. Ultrasound also can be used to determine the sex of the fetus and incidence of twins.
The frequency of embryonic mortality typically is highest within the first 42 days of pregnancy. In some cases, producers have attributed abortions to rough handling of the fetus and/or membranes when pregnancy testing; however, differentiating these potential losses with “normal” embryonic loss is extremely difficult.
For cattle in early pregnancy, minimize handling, transportation and heat stress to reduce the risk of abortions, Stokka advises. If necessary, an additional pregnancy check conducted before winter feeding programs begin can identify cows that have lost pregnancies.
“There are advantages and disadvantages for each method of pregnancy testing,” Stokka says. “Costs are typically similar among methods; however, it is important to evaluate options due to variation in prices among veterinarians and laboratories.”Source: NDSU Extension Service, which is solely responsible for the information provided and is wholly owned by the source. Informa Business Media and all its subsidiaries are not responsible for any of the content contained in this information asset.