**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** PREGNANCY LOSS DURING THE SECOND MONTH OF PREGNANCY IN CATTLE CAN VARY FROM 4% TO UP 50% AND HAS MARKED DETRIMENTAL EFFECTS ON REPRODUCTIVE EFFICIENCY AND PROFITABILITY OF CATTLE OPERATIONS. MATERNAL RECOGNITION OF PREGNANCY (MRP) IS THE PROCESS BY WHICH THE EMBRYO WITHIN THE UTERUS SIGNALS ITS PRESENCE TO THE MOTHER TO PREVENT REGRESSION OF AN OVARIAN ENDOCRINE GLAND, THE CORPUS LUTEUM (CL), AND SUSTAIN PROGESTERONE (I.E., PRO-GESTATION) PRODUCTION A CRITICAL HORMONE REQUIRED TO MAINTAIN PREGNANCY. THE TRADITIONALLY ACCEPTED PERIOD FOR MRP IN CATTLE OCCURS DURING THE FIRST MONTH AFTER CONCEPTION AND MECHANISMS FOR THIS PROCESS ARE WELL UNDERSTOOD BUT NO LONGER EXIST AFTER THE FIRST MONTH OF PREGNANCY. TO PREVENT PREGNANCY LOSSES AFTER THE FIRST MONTH OF PREGNANCY, DETAILED KNOWLEDGE IS REQUIRED OF THE MECHANISM RESPONSIBLE FOR MAINTENANCE OF THE CL - THE PRO-GESTATIONAL STRUCTURE. THE PROPOSED RESEARCH WILL INVESTIGATE THE MECHANISMS INVOLVED IN EMBRYO-SIGNALING TO THE MATERNAL SYSTEM TO MAINTAIN THE PRO-GESTATIONAL ENDOCRINE STRUCTURE, THE CL, AFTER THE FIRST MONTH OF PREGNANCY. FIRST, WE WILL EVALUATE THE CHANGES IN UTERINE BLOOD FLOW WHEN PREGNANCY IS SUSTAINED OR WHEN ABORTION OCCURS AND DETERMINE WHETHER THE AMOUNT OF UTERINE BLOOD FLOW HAS AN EFFECT ON THE FUNCTION OF THE MATERNAL PRO-GESTATIONAL GLAND. SECOND, WE WILL EVALUATE WHETHER MAINTENANCE OF THIS GLAND DURING THE SECOND MONTH OF PREGNANCY REQUIRES AN EMBRYO SPECIFIC SIGNAL. THIRD, WE WILL EVALUATE THE SECRETION PATTERN FROM THE UTERUS OF SPECIFIC PROSTAGLANDINS (PGF2Α AND PGE2) THAT ARE KNOWN TO REGULATE FUNCTIONS OF THE PRO-GESTATIONAL GLAND WHEN PREGNANCY IS SUSTAINED OR WHEN ABORTION OCCURS. WE ANTICIPATE THAT MAINTENANCE OF THE MATERNAL PRO-GESTATIONAL GLAND AND PREGNANCY CAN OCCUR EITHER BY INCREASING UTERINE BLOOD FLOW WHICH RESULTS IN DECREASED TRANSFER OF PGF2Α, A HORMONE THAT INDUCES CL REGRESSION, FROM THE UTERUS TO THE OVARY, THUS PREVENTING REGRESSION OF THIS GLAND; AND/OR A CONCEPTUS DERIVED SUBSTANCE BEING SECRETED SUBSEQUENT TO THE FIRST MONTH OF GESTATION THAT PREVENTS REGRESSION OF THIS PRO-GESTATIONAL GLAND EVEN WHEN PGF2Α IS PRESENT. KNOWLEDGE GENERATED FROM CONDUCTING THE PROPOSED RESEARCH WILL ENHANCE UNDERSTANDING OF MECHANISMS INVOLVED IN MATERNAL-FETAL COMMUNICATION BETWEEN THE MATERNAL PRO-GESTATIONAL GLAND (I.E., CL) AND FETUS DURING A PERIOD WHEN THERE ARE SIGNIFICANT PREGNANCY LOSSES IN CATTLE. ULTIMATELY THIS KNOWLEDGE CAN BE UTILIZED TO DEVELOP NEW STRATEGIES TO REDUCE PREGNANCY LOSS AND THUS IMPROVE REPRODUCTIVE EFFICIENCY AND, THEREFORE, PRODUCTION EFFICIENCY OF CATTLE ENTERPRISES.

Ohio State University, The, Columbus OH

Investigators