DNA could solve puzzling cattle fertility decline

Neibergs with her cattle on her Palouse farm, with view of clouds, rolling hills.
Holly Neibergs, professor of Animal Sciences at Washington State University, leads a half-million-dollar research project into the genetic roots of cattle fertility.

In cattle production, nothing is more important than fertility. Without it, herds can’t grow and milk doesn’t flow.

For decades, fertility in U.S. dairy cattle has been on a drastic decline. Every failure to conceive throws off the herd’s delicate rhythm of production, making it harder for farmers to deliver milk and other foods we love.

Holly Neibergs, animal scientist at Washington State University, is studying the cause of this complex problem.

Exploring the genetic roots of fertility in hopes of halting the decline, she launched a three-year, $500,000 research project this spring, funded by the U.S. Department of Agriculture’s National Institute of Food and Agriculture.

Falling fertility

Farmers have watched in concern as dairy cattle fertility has fallen dramatically over the past 30 years.

Today, on average, cows and heifers—first-time mother cows—will successfully conceive more than 90 percent of the time.  In beef cattle, 60 percent or fewer cows will still be pregnant 35 days later. In dairy cows, the rate is even worse, about 30 percent.

“It’s taking more tries to get cattle pregnant,” Neibergs said. “Every pregnancy loss costs farmers as much as $600. If your heifers are losing a third of their pregnancies, that adds up fast.”

“Infertility is a huge and costly problem,” she added.

With more time to stay with their mothers before weaning, calves born on time are bigger, healthier, heavier, and have more value.

“But every time you miss, the chance that that calf is going to stay with the herd and be productive becomes more and more remote,” Neibergs said. “A well-timed pregnancy is better for the cow, the calf, the herd—and the bottom line.”

Answers in the DNA

Studying cattle fertility for more than a decade, Neibergs believes fertility decline is related to a cow’s uterine environment, which is partly determined by genetics. Cows with poor fertility may have DNA mutations that make it harder for them to successfully stay pregnant.

Working with collaborators Christopher Seabury at Texas A&M, Jeremy Taylor and  Thomas Spencer at the University of Missouri, and Thomas Geary at the U.S. Department of Agriculture, Neibergs and her students will compare DNA from cows with great pregnancy rates to those with poor fertility. That involves analyzing hundreds of thousands of genetic fingerprints from more than 3,000 beef and dairy cows across a range of breeds.

“We’re looking for DNA associated with fertility, conception, and maintaining pregnancy,” she said. “We’re going to find the differences in their DNA that are making their uterine environment different—fertile for one, infertile for another.”

Once they find those genetic markers, cattle breeders will be able to select for fertility, breeding cattle that maintain pregnancy successfully and predictably. Animal scientists could also find new opportunities to develop fertility treatments.

Solving the fertility challenge will help dairy farmers meet the growing global demand for milk and other dairy products at a lower cost, ensuring consumers have an affordable supply of the foods we enjoy.

“With just a blood sample, we will be able to tell which calves will have high fertility, as soon as they’re born,” Neibergs said. “Instead of a decline, we’d see a fertility increase—and healthier, more valuable and more productive beef and dairy herds.”