** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** THIS RESEARCH PROJECT FOCUSES ON IMPROVING HOW OFTEN DAIRY COWS SUCCESSFULLY HAVE CALVES, AN IMPORTANT AREA FOR U.S. AGRICULTURE. SPECIFICALLY, THE PROJECT LOOKS AT WHY HIGH-PRODUCING DAIRY COWS (THOSE THAT GIVE A LOT OF MILK) OFTEN HAVE PROBLEMS WITH PREGNANCIES THAT DO NOT GO TO TERM, PARTICULARLY DUE TO EARLY DEATH OF EMBRYOS. THIS ISSUE IS COSTLY FOR FARMERS AND STEMS FROM COMPLEX BIOLOGICAL PROBLEMS NOT YET FULLY UNDERSTOOD. LACTATING COWS EXPERIENCE CHANGES IN THEIR BODY ENERGY DUE TO INTENSE MILK PRODUCTION RIGHT AFTER GIVING BIRTH. THESE CHANGES CAN NEGATIVELY AFFECT THE COWS' REPRODUCTIVE ORGANS AND EMBRYO HEALTH.THE OVERALL HYPOTHESIS OF THIS RESEARCH IS THAT THE BALANCE OF OXYGEN AND SUGAR LEVELS, CONTROLLED BY THE ENVIRONMENT INSIDE THE UTERUS, PLAYS A CRUCIAL ROLE IN THE EARLY DEVELOPMENT OF EMBRYOS AND THEIR STEM CELLS, ULTIMATELY INFLUENCING WHETHER THEY CAN SUCCESSFULLY ATTACH TO THE UTERUS AND CONTINUE DEVELOPING.THE STUDY HAS TWO MAIN GOALS:1. UNDERSTANDING EMBRYO NEEDS: BY MEASURING SUGAR AND OXYGEN LEVELS IN THE UTERUS, THE RESEARCH AIMS TO FIND OUT WHAT EMBRYOS NEED TO DEVELOP HEALTHILY AND IF THESE NEEDS ARE DIFFERENT IN COWS THAT ARE LACTATING COMPARED TO YOUNGER HEIFERS. THIS COULD LEAD TO BETTER UNDERSTANDING OF HOW TO SUPPORT EMBRYO GROWTH DURING EARLY STAGES.2. STUDYING GENE ACTIVITY: THE PROJECT ALSO PLANS TO EXAMINE HOW SUGAR AND OXYGEN LEVELS INFLUENCE EMBRYO DEVELOPMENT AT THE GENETIC LEVEL. THIS INVOLVES LOOKING AT HOW GENES IN THE EMBRYOS ARE TURNED ON OR OFF BY THESE CONDITIONS AND COULD TELL US MORE ABOUT WHY SOME EMBRYOS FAIL TO DEVELOP PROPERLY.THE FINDINGS FROM THIS RESEARCH COULD LEAD TO BETTER WAYS TO HELP COWS HAVE SUCCESSFUL PREGNANCIES AND IMPROVE METHODS FOR CREATING EMBRYOS IN THE LAB (IN VITRO). THIS WOULD NOT ONLY HELP REDUCE FINANCIAL LOSSES FOR FARMERS BUT ALSO ENHANCE THE PRODUCTIVITY AND SUSTAINABILITY OF DAIRY FARMING.