** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** ONLY 50% OF EGGSWILL RESULT IN A SUCCESSFUL PREGNANCY FOR COUPLES UTILIZING IN VITRO FERTILIZATION (IVF), THEREFORE, THERE IS A CRITICAL NEED TO IDENTIFY METHODS TO IMPROVE IVF EFFICIENCY TO ADDRESS INFERTILITY CHALLENGES IN HUMANS AND OTHER MAMMALS. COWS SHARE SIMILAR UNDERLYING FERTILITY ISSUES WITH WOMEN, SUCH AS A LOW RESERVE OF EGGS AS THEY AGE, MAKING THEM AN EXCELLENT MODEL SPECIES FOR INFERTILITY RESEARCH. THIS STUDY WILL TEST THE HYPOTHESIS THAT MELATONIN (MEL) SUPPLEMENTATION DIRECTLY TO COWS AND TO BOVINE EGGS AFTER COLLECTION WILL IMPROVE EMBRYODEVELOPMENT AND IVF EFFICIENCY.IN OUR FIRST STUDY, WE WILL IDENTIFY COWS WITH A HIGH AND LOW RESERVE OF EGGS AND THEN GIVE HALF OF EACH GROUP A MEL SUPPLEMENT BEFORE WE COLLECT EGGS TO DETERMINE WHETHER SUPPLEMENTATION CAN IMPROVE THE QUALITY AND SURVIVAL OF THESE EGGS FOR THE IVF PROCESS. FOR THE SECOND STUDY, WE WILL UTILIZE COWS WITH A HIGH AND LOW EGG RESERVE, COLLECT EGGS FROM THEM AND THEN SUPPLEMENT HALF OF THE EGGS FROM EACH GROUP WITH MEL DURING THE IVF PROCESS, TO DETERMINE IF SUPPLEMENTATION AFTER COLLECTION CAN IMPROVE DEVELOPMENT AND SUCCESS.WE EXPECT TO FIND THAT SUPPLEMENTING COWS DIRECTLY WILL IMPROVE THE QUALITY OF EGGS THAT ARE COLLECTED, SPECIFICALLY FOR COWS THAT HAVE A LOW EGG RESERVE WHEN COMPARED TO COWS NOT SUPPLEMENTED WITH MEL. WE ALSO EXPECT THAT WHEN EGGS ARE COLLECTED AND THEN SUPPLEMENTED WITH MEL DURING THE IVF PROCESS, MORE OF THE EGGS WILL DEVELOP AND GROW SUCCESSFULLY COMPARED TO EGGS NOT SUPPLEMENTED WITH MEL.THIS RESEARCH WILL NOT ONLY INCREASE OUR UNDERSTANDING OF HOW MEL INTERACTS WITH EGGS AND INFLUENCES EMBRYODEVELOPMENT BUT WILL ALSO DEVELOP A NEW TOOL THAT CAN BE UTILIZED IN BOTH HUMAN AND ANIMAL MEDICINE TO INCREASE PREGNANCY ESTABLISHMENT AND IMPROVE THE IVF PROCESS.