By Dr. Jessica Nora Drum And Dr. Rebecca Swanson
As cattle producers, particularly in spring-calving herds, prepare for winter, much of their focus centers on maintaining body condition in late-gestation cows. However, feed costs are often the largest expense in a cow-calf operation, and winter nutrition decisions require balancing economics with cow performance. Beyond keeping cows in adequate condition until calving, winter feeding during late gestation offers a key opportunity to influence the next generation's development and future performance.
Recent research from regional institutions, including studies involving Dr. Rebecca Swanson and Dr. Ana Clara Baiao Menezes at South Dakota State University, continue to demonstrate that the nutritional environment experienced by a fetus can affect developmental processes long before birth. This concept, known as fetal programming, suggests that management decisions made during gestation may have lasting consequences for offspring growth, metabolism, health, and productivity (Hurlbert et al., 2026; Jardon et al., 2025; Kennedy et al., 2026; R. Swanson et al., 2022a; R. M. Swanson et al., 2026; Wehrbein et al., 2026a, b).
The Importance of Late Gestation
The final third of pregnancy is one of the most critical periods as rapid fetal growth occurs, increasing the demand for nutrients. Any changes in nutrient availability must be managed through the placenta, which serves as the bridge between the cow and her developing calf. The placenta is not simply a passive connection. It actively regulates the transfer of amino acids, fatty acids, and other nutrients needed for fetal growth (Kennedy et al., 2026 ; Swanson et al., 2022).
A recent study co-authored by Dr. Rebecca Swanson examined how nutrient restriction during mid to late gestation affects nutrient transfer between the dam and fetus. Researchers found that reducing maternal nutrition altered fetal fatty acid profiles and changed the expression of genes involved in placental nutrient transport. These findings demonstrated that the placenta adapts to nutritional challenges and may respond by modifying how nutrients are delivered to the developing fetus (Kennedy et al., 2026).
The same research group previously reported that late-gestation nutrient restriction influenced maternal and fetal amino acid concentrations as well as placental amino acid transport systems ( Swanson et al., 2022b). Together, these studies reinforce an important principle: the nutritional environment experienced during pregnancy can directly influence fetal development.
Source : sdstate.edu