Graduate Student Literature Review: Precision nutrition meets cellular insight—The mechanistic role of oleic acid in dairy cow metabolism

Dairy cows going through the transition period experience a state of negative energy balance, driven by a mismatch between rising energy needs and reduced feed intake. Although fat breakdown (i.e., lipolysis) is a necessary adaptation to meet rising energy demands, excessive and prolonged lipolysis can increase disease risk. One strategy to mitigate this gap in energy is by increasing the energy density of the diet through fatty acid (FA) supplementation. Among available FA, oleic acid (OA) has gained attention not only as an energy source, but also for its broader biological effects. This review examines the role of OA in dairy cow metabolism, extending beyond its caloric contribution to its regulatory influence on lipid metabolism, insulin signaling, oxidative stress, and inflammation. We summarize findings from both ruminants and nonruminants to provide mechanistic insights into how OA modulates cellular pathways and contributes to metabolic adaptations, especially within adipose tissue during periods of physiological stress. Additionally, we highlight the nutritional implications of OA on production outcomes such as milk yield and composition, as well as its effects on adipose tissue. By integrating nutritional and mechanistic perspectives, this review provides a comprehensive evaluation of OA potential as a functional nutrient to support health and performance in transition dairy cows.