There’s a critical window of time for cattle producers to determine whether females in the herd are pregnant.
In the Central Plains region, including Nebraska and Kansas, veterinarians like to begin preg-checking spring calving herds in mid-September. The work ramps up from there, with the bulk of the preg-checks conducted in October and November.
The earlier producers determine the pregnancy status of the cow, the sooner they can make management decisions regarding open cows.
“Most open cows will be culled from the herd since they will not fit into the prescribed calving season,” said Tony Hawkins, DVM, technical services veterinarian at Valley Vet Supply in Marysville, Kansas.
So, the question is, how early to preg-check?
“The sooner/the better,” advises beef cattle veterinarian Dr. Bob Larson at Kansas State University.
He prefers to preg-check when he expects the pregnancies to be at least 35-40 days or older. Veterinarians can be pretty accurate when using that time frame.
Some vets palpate manually while others use ultrasound to verify a pregnancy. Ultrasound is used more for early pregnancies. Veterinarians can be more accurate at determining the age and size of the fetus by checking early, Larson said.
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With early checks, producers can identify cows that are not pregnant and manage them differently. If they’re not going to have a calf, producers don’t want to invest a winter feed bill for them, Larson said. Once determining a cow is open, producers will either feed them separately to put weight on before selling her or sell her right after the open diagnosis.
Another important factor to consider is estimating when each cow got pregnant, Larson said. He calls it “value-added” pregnancy checking, and it’s especially critical for a herd that doesn’t breed up as well as expected. It helps narrow the time periods within the breeding season when cows were not becoming pregnant.
Several factors impact whether cows become pregnant, and also how early in the breeding season they become pregnant. There’s nutrition, genetics, animal husbandry, bull fertility and cow health at influence pregnancy.
Larson likes to pinpoint when the herd might not have been performing well reproductively.
“Maybe they bred well in the beginning. Then because of bull problems or other issues the herd didn’t breed well for a few weeks, although later on they performed well again,” Larson said.
He recommends determining not only if they became pregnant, but when to pinpoint the problem.
Some producers have other reasons for choosing when they preg check.
Many wait until cows will be at the appropriate stage of gestation to vaccinate them at the same time, Hawkins said. Though, that could mean feeding open cows for several months.
“While this results in a higher feed bill, you only have to process the cows once,” he said.
Reporter Amy Hadachek is a two-time Emmy Award winning meteorologist and a storm chaser who earned her NWA and AMS Broadcast Meteorology Seals of Approval. She and her husband live on a diversified farm in Kansas. Reach her at firstname.lastname@example.org.