A team of South Dakota State University (SDSU) researchers who hope to use “fetal programming” to produce better beef has been awarded a $320,000 grant from USDA.

Amanda Weaver, SDSU meat scientist and project leader, says the idea is that the cow’s diet – perhaps during the crucial second trimester of pregnancy, in particular – sends signals to the fetus that affect how efficiently that calf will use nutrients. The possibilities for managing those signals are what tantalize her.

“We would like the animals to use those nutrients to build muscle and to deposit what we call marbling, which is the intramuscular fat, that gives beef flavor and juiciness and aids in tenderness somewhat,” she says. “We would like them to not deposit a lot of external fat because that would be waste or trim, and that is going to decrease the value of the animal.”

Weaver developed the idea for the beef study while pondering existing research on human health and diet. In particular, she investigated studies that looked at the effects of famine, such as in the Netherlands near the end of World War II.

Human nutrition research has shown that when a mother is either in a starvation state or possibly obese during pregnancy, her nutritional state during gestation affects the development of the fetus, Weaver says.

“For example, researchers showed that during the Dutch famine, some women who were pregnant were getting only 500-600 calories/day. A study of the offspring found problems with metabolic syndrome, diabetes, obesity. Their thought was that during gestation, the mother’s signal to the fetus was, you need to prepare for a situation with low food availability. The offspring therefore were very, very efficient, and when they came into the world and there was enough food, then they had problems with diabetes and obesity,” she says.

With Weaver’s current research in fetal programming in beef cattle, the idea is to explore how different genes are signaled – turned on, turned off – during fetal development to create the phenotype of the offspring.

One of Weaver’s co-investigators on the project, James Reecy, director of Iowa State University’s Office of Biotechnology, says it’s an exciting and practical area of research. “Through a better understanding of the effect of prenatal nutrition on subsequent post-natal growth, we facilitate the development of strategies designed to enhance production efficiency.”

In addition to the USDA grant, the South Dakota Beef Industry Council (SDBIC) is also supporting the project with $30,000, bringing the total for the project to $350,000. SDBIC had supported Weaver’s earlier preliminary work with a $100,000 grant, which allowed Weaver and her colleagues to gather the necessary data to receive the USDA grant.

The researchers in that first stage of the research divided a group of bred heifers into three groups during gestation. One group was on a high level of nutrition, one was on an intermediate level of nutrition, and one was on a low level of nutrition. Researchers removed the fetuses by Cesarean sections at 188 days of gestation and sampled muscle tissue and fat, and gathered weights and measurements. The preliminary work proved researchers’ hypothesis right in another way – nature looks after the next generation, even when resources are scarce.

“Even those cows that were on a lower plane of nutrition, their fetuses were not any smaller than the ones that were on an intermediate or higher plane of nutrition. The heifer was giving the fetus what it needed to grow. However, there were differences in how much fat and muscle was there. It was, for us, very strong preliminary data that you can affect composition of the fetus based on a cow’s nutrition,” Weaver says.

It was on the strength of those findings that USDA awarded its $320,000 grant to fund the next step of the research, one of only 13 projects funded out of more than 80 proposals.

Weaver is the principal investigator. Her co-principal investigators are SDSU Extension meats specialist Keith Underwood, SDSU assistant professor Aimee Wertz-Lutz, and SDSU distinguished professor Robbi Pritchard, all of SDSU’s Department of Animal and Range Sciences; as well as Reecy.

“We designed this large study to look at cattle on a normal plane of nutrition through gestation vs. a low plane of nutrition. So we’re trying to mimic common practice in South Dakota and the surrounding states while that cow is gestating,” Weaver says. “We’re particularly interested in the second trimester. From some investigations, we feel that’s the key point for development of a lot of these tissues. If there are going to be changes, we feel like it’s going to occur in the second trimester. The third trimester is where we tend to see a lot of body growth.”

Weaver says animals will be split into two groups, one fed to maintain body condition, while the other will be fed to lose some body condition, in the second trimester. In the third trimester, during calving and through weaning, the cows will be treated as they normally would. After weaning, calves from the two groups will be fed at the SDSU feedlot, and monitored to see whether weaning weights, post-weaning efficiency and health were altered by gestation diets.

“We want to see how the altered plane of nutrition during the second trimester affected them all the way through growth. We’ll follow them through harvest, collect the carcass data used to determine yield and quality grade, and tenderness, and do a lot of meat quality work on those carcasses,” she says.

Weaver says whatever the outcome, more information on whether curtailed nutrition in the second trimester affects meat quality or whether it doesn’t – will be positive for the producer.

“Either way, we’re going to get information to the producers that they can use,” Weaver says. “With this project, I feel that we’ll be able to give something back to the producers very quickly.”
-- Lance Nixon, SDSU news release