biostudies-literatureGonzalez-Brusi LState of Louisiana Board of RegentsLouisiana State University School of Animal Sciences laboratory start-up fundingEuropean Research CouncilScience Foundation IrelandSpanish Ministry of Science, Innovation and UniversitiesJoe W. and Dorothy Dorsett Brown FoundationUnited States Department of Agriculture (USDA) Research Capacity (Hatch)Audubon Center for Research of Endangered Species134-145https://www.ebi.ac.uk/biostudies/studies/S-EPMC12808546biostudies-literatureUnknown114(1)An optimal uterine luminal fluid (ULF) microenvironment is essential for successful pregnancy establishment and progression. Despite this, the specific factors influencing early embryo and conceptus (embryo and extra-embryonic structures) survival remain poorly understood. Lipid moieties dominate the ULF metabolome and are thought to play crucial roles in embryo and conceptus development. As such, we aimed to comprehensively profile the bovine ULF lipidome at four key times of the estrous cycle-Days 0, 7, 10, and 14. Our analysis identified 80 distinct lipids, which were categorized into 29 metabolic pathways. We observed significant (P ≤ 0.05) temporal variation in lipid abundance, with certain lipids uniquely present on specific days. Notably, carnitine derivatives exhibited pronounced cBiology of reproductionBovine uterine fluid lipidome parallels embryo and conceptus developmental milestones†.PMC12808546StG-757886-ELONGANBG008584LAB-94578JDC2022-049435-IPID2023-151241OB-I00LEQSF(2023-26)-RD-A-03GR-0001380016/IA/4474Simintiras CADevkota IGonzalez-Brusi LLamas-Toranzo IBermejo-Alvarez PSanchez JMLonergan PfalseBovine uterine fluid lipidome parallels embryo and conceptus developmental milestones†.An optimal uterine luminal fluid (ULF) microenvironment is essential for successful pregnancy establishment and progression. Despite this, the specific factors influencing early embryo and conceptus (embryo and extra-embryonic structures) survival remain poorly understood. Lipid moieties dominate the ULF metabolome and are thought to play crucial roles in embryo and conceptus development. As such, we aimed to comprehensively profile the bovine ULF lipidome at four key times of the estrous cycle-Days 0, 7, 10, and 14. Our analysis identified 80 distinct lipids, which were categorized into 29 metabolic pathways. We observed significant (P ≤ 0.05) temporal variation in lipid abundance, with certain lipids uniquely present on specific days. Notably, carnitine derivatives exhibited pronounced c2026-01-01T00:00:00Z2026 Jan2026-06-10T05:23:40.124Z2026-06-10T03:07:27.752ZS-EPMC128085464083870110.1093/biolre/ioaf194