WEST LAFAYETTE, Ind. – A new USDA-funded research project at Purdue University will examine early pregnancy loss in cattle, which often occurs before a pregnancy is even recognized, causing significant economic loss for cattle producers, according to researchers.

Supported by a four-year, $650,000 New Investigator Award from the USDA’s National Institute of Food and Agriculture, the research will focus on the earliest stage of pregnancy, when an embryo first communicates with the mother, researchers said.

Viju Pillai, Purdue University College of Veterinary Medicine assistant professor of anatomic pathology and project leader, said early embryonic loss is a major challenge in modern cattle systems.

The study will place special attention on proteins called trophoblast Kunitz domain proteins, which may play a key role in successful pregnancy, he said. Even though advances in genetics and production have improved milk and meat yield, reproductive efficiency has not kept pace.

He added the first few weeks of pregnancy are especially vulnerable, and failures during this window can lead to substantial economic losses for producers through missed breeding cycles, extended calving intervals, and reduced lifetime productivity.

“Pregnancy does not begin with a visible sign; it begins with a signal,” he said in an April 10 media statement. “Within the first week, the embryo must effectively ‘introduce itself’ to the mother. If that molecular dialogue falters, the pregnancy can quietly end before it truly begins.”

To address this challenge, Pillai’s Laboratory of Developmental and Stem Cell Biology is developing and deploying experimental models that recreate key features of early pregnancy outside the animal, creating this accessible window into events that are otherwise difficult to observe, researchers said.

Central to this work are these trophoblast cells, the specialized cells that build the placenta and serve as an essential interface between the embryo and the uterus, researchers said. By growing these cells under carefully controlled conditions that mimic the uterine environment, researchers added that they have established platforms in which trophoblast cells not only survive, but also differentiate into placenta-forming cell types that resemble those seen in early gestation.

Grant Dewell, Iowa State University associate professor of veterinary medicine and extension beef veterinarian, told Farm World the potential loss of early embryos can be quite high, with some estimates of 30 to 50 percent not resulting in pregnancy.

“As you can imagine, there are intricate details required for the cow’s normal estrus cycle to stop and shift toward pregnancy maintenance that actually requires all three factors (bull, cow and embryo) to be in sync, plus there are environmental factors as well,” he said. “To minimize problems, producers and veterinarians need to reduce stress prior to breeding season.”

The estrus cycle is a recurring, hormone-driven reproductive cycle in female animals.

He added, “If the ovulated egg has had any insults prior, then even if it gets fertilized, the embryo may not be able to adequately release pregnancy-associated glycoproteins that signal for pregnancy to begin, and the cow’s uterus has to be able to read the signals as well.” According to Iowa State, glycoproteins are proteins that bond to carbohydrate units (sugars), often functioning in immune responses, cell signaling, and structural integrity.

Dewell said, however, well before the breeding season begins, the nutritional and health needs of the cows first need to be met to allow for pregnancy to be successful: “At the beginning of breeding season, we also add stress such as synchronization programs, changing diet at pasture turn out, and transportation stress. Recognizing ways to minimize these external stressors can help set the cow up to maintaining pregnancy from the beginning.”

He added, “We don’t know a lot about the bull’s influence, but we do know that the sperm cell influences the pregnancy-associated glycoproteins as well, either from genetics or other factors such as the bull’s nutritional and health status.”

Andrew P. Griffith, University of Tennessee professor of agricultural and resource economics, told Farm World, “Research from South Dakota State University says the early pregnancy loss percent is 20 to 30 percent. I guess one could say this, given that about 60 percent of a calf crop tends to be born in the first 21 to 28 days of a calving season.

“We know there can be several reasons an animal loses a pregnancy, including but not limited to, nutrition, stress (i.e., hauling, environmental factors), trauma or others,” he said. “However, the economic implications of an animal experiencing early pregnancy are huge. It is widely established that the calves born earlier in the calving season will be heavier at weaning because they are older than other calves at the time of weaning.”

He said most calves will gain about two pounds per day while nursing if nutrition is adequate to do that: “This means a female missing on one cycle could cost 42 pounds, and it is likely it will be more than that.”

He said that 42 pounds at today’s prices would result in calves that return $100 to $150 less than their heavier counterparts: “If the 20 to 30 percent number is correct, a producer with 50 cows could have 10 to 15 cows impacted, which would mean $1,000 to $2,500 less in revenue that year. The impact is much smaller when prices are lower.”

Researchers said the long-term goal of the study is to identify practical solutions that help reduce reproductive loss and improve cattle production sustainability