This article was originally published in Wisconsin Agriculturist Magazine

Beef producers have several options for conducting early pregnancy diagnosis on their herd. High feed costs and limited forage inventories are reasons to consider using pregnancy diagnosis this year if it is not part of your current herd management. Several pregnancy diagnosis methods are available to beef producers. Don’t let open cows eat your feed, and profits, this winter.

Remember the real value of pregnancy diagnosis is not finding pregnant cows, but open cows. Identifying open cows early presents an opportunity for herd managers to make decisions. Will open cows be marketed, or given another breeding opportunity? If marketed, when?

Pregnancy Diagnosis Methods

For many producers, rectal palpation conducted by a veterinarian, has been and remains the gold standard. More options exist, though, with their own pros and cons. Four of the more common options are:

Direct detection (feeling or visualizing the fetus):

• Transrectal palpation: Accurate beginning 35 days after breeding. Experienced veterinarians can estimate the conception date (and thus expected calving date) if unknown and they can diagnose uterine and ovarian diseases, if present. The result is known immediately. Adding pregnancy palpations to your herd health program adds the opportunity to build your Veterinarian Client Patient Relationship (VCPR).
• Transrectal ultrasound: Accurate beginning 30 days after breeding. Experienced veterinarians can estimate the conception date (and thus expected calving date) if unknown and they can diagnose uterine and ovarian diseases, if present. Can diagnose cows carrying twins and fetal viability. Fetal sexing is possible 55 to 60 days after conception. Result is known immediately. This is also an opportunity to build your Veterinarian Client Patient Relationship.

Indirect detection (biological lab testing)

• Pregnancy Associated Glycoproteins (PAG’s): Accurate beginning 25-30 days following breeding. Cows need to be 70-75 days post calving. Follow label directions specific to the test you select. Sample can be collected by blood or milk by the herd manager and submitted to a lab for analysis. Costs for testing supplies and shipping vary but may be a more cost-effective approach for some farms. Result is not known immediately as it is dependent on transport time and lab analysis.
• Progesterone tests: progesterone is the hormone responsible for maintaining pregnancy. Sampled through blood or milk, a low level detected indicate an open cow. A high progesterone level detected does not ensure pregnancy, since it is also elevated during most of the animal’s reproductive cycle. Repeated testing raises reliability, but is not practical on most beef operations, which limits its usefulness to beef producers.

No matter the method you select, use recommended animal handling practices. Keep and use accurate records to get the most value out of your pregnancy diagnostics.

Not every cow diagnosed pregnant will calve. Some early embryonic death is natural. However, rough handling and stress created at the time of pregnancy diagnosis can have a negative impact on fetal viability and increase the rate of early embryonic death.

In years with plentiful feed and favorable cattle prices, waiting to market open cows after the fall rush can be a viable strategy, along with giving cows a second chance for a fall calving season. However, in years with limited feed inventories and high feed prices we encourage producers to calculate the amount of feed needed to carry open cows through the winter. If feed inventories are limited, marketing open cows is one of the first herd reduction strategies to implement. Culling Consideration for the Beef Cow-Calf Herd provides more information on market cow strategies.

Resources:

Gunn, D., and J. B. Hall, Pregnancy Testing in Beef Cattle, 2018, University of Idaho Extension BUL 913, https://www.extension.uidaho.edu/publishing/pdf/BUL/BUL913.pdf Accessed 6-25-2021

Senger, P.  Pathways to Pregnancy and Parturition, 2nd edition.

Silva, E., Sterry RA, Kolb D, Mathialagan N, McGrath MF, Ballam JM, Fricke PM. Accuracy of a pregnancy-associated glycoprotein ELISA to determine pregnancy status of lactating dairy cows twenty-seven days after timed artificial insemination.  J. Dairy Sci. 90:4612-4622; 2007.

Sterry, RA, and W. Halfman, Culling Considerations for the Beef Cow-Calf Herd, 2020, UW-Madison Division of Extension. https://livestock.extension.wisc.edu/articles/culling-considerations-for-beef-cow-calf-herd/ Accessed 6-28-2021.

Reviewed by:  Bill Halfman UW Extension Agriculture Agent in Monroe County, and Sandy Stuttgen, D.V.M, UW Extension Educator in Taylor County.