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. 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 in beef cattle
For many producers, rectal palpation conducted by a veterinarian has been and remains the gold standard in pregnancy detection. More options exist, though, with their own pros and cons.
Common direct detection (feeling or visualizing the fetus) options include:
Transrectal palpation. This is 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, or VCPR.
Transrectal ultrasound. This is 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. They can diagnose cows carrying twins and fetal viability. Fetal sexing is possible 55 to 60 days after conception. The result is known immediately. This is also an opportunity to build your VCPR.
Indirect detection (biological lab testing) options include:
Pregnancy Associated Glycoproteins (PAGs). This is accurate beginning 25 to 30 days following breeding. Cows need to be 70 to 75 days post-calving. Follow label directions specific to the test you select. Samples 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 this may be a more cost-effective approach for some farms. The result is not known immediately, as it depends on transport time and lab analysis.
Progesterone tests. Progesterone is the hormone responsible for maintaining pregnancy. Sampled through blood or milk, a low level indicates an open cow. A high progesterone level does not ensure pregnancy, because 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 this test’s 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 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. Please see our article “Culling Consideration for the Beef Cow-Calf Herd” on the Extension Livestock Topic Hub for more information on market cow strategies.
Sterry is the St. Croix County Extension agriculture agent. This column is provided by the University of Wisconsin Division of Extension Livestock Team. Visit livestock.extension.wisc.edu.