** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** U.S. SWINE HERD REPRODUCTIVE PERFORMANCE IS IMPORTANT TO PORK PRODUCTION, THOUGH IT IS LIMITED BY SIRE INFERTILITY. SPERM FERTILITY REFLECTING BIOMARKERS EXIST BUT HAVE FAILED TO BE ADOPTED BY INDUSTRY. FURTHER, OUR BASIC UNDERSTANDING OF SPERM FERTILIZATION COMPETENCY IS LIMITED. OUR OVERARCHING GOAL IS TO DESCRIBE THE BIOCHEMICAL MAKEUP OF FERTILE SPERM AND TO TRANSLATE FERTILITY BIOMARKERS TO STAKEHOLDER-RELEVANT METHODS. OUR SPECIFIC OBJECTIVES ARE TO: 1) IDENTIFY BIOCHEMICAL DIFFERENCES RELATED TO SPERM FERTILITY; AND 2) TRANSLATE SPERM HEALTH-REFLECTING BIOMARKERS TO METHODS THAT ARE EASIER AND LESS COSTLY TO PERFORM IN THE FIELD. WE EXPECT TO IDENTIFY DIFFERENCES IN THE BIOCHEMICAL MAKEUP OF SPERM THAT ARE MORE AND LESS FERTILE. FURTHER, WE EXPECT TO IDENTIFY BIOMARKERS THAT CAN BE TRANSLATED FOR USE BY LESS COSTLY EQUIPMENT IN THE FIELD. WORK DONE UNDER THIS STUDY WILL HELP FURTHER OUR UNDERSTANDING OF THE MOLECULAR MECHANISMS OF BOAR SPERM FERTILITY AND INFERTILITY. IT WILL ALSO ALLOW FOR FUTURE TRANSLATION OF SPERM BIOMARKER DIAGNOSTICS INTO METHODS THAT ARE MORE COST-EFFECTIVE AND REQUIRE LESS TIME FOR FARMERS IN THE FIELD. THIS IS CRITICAL BECAUSE CURRENT METHODS ARE NOT USED IN THE FIELD DUE TO THE HIGH COST OF EQUIPMENT, THE TIME, AND THE HIGH LEVEL OF TRAINING REQUIRED TO USE.