** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** THE CONCERN FOR FARM ANIMAL HEALTH AND WELFARE HAS INCREASED IN THE PAST FEW DECADES. ANIMAL HEALTH AND WELFARE ARE GENERALLY ASSESSED BY PHYSICAL HEALTH, IMMUNE RESPONSE, BEHAVIOR, AND OTHER PHYSIOLOGICAL INDICATORS, INCLUDING STRESS-RELATED BIOMARKERS. THE STRESS THE SOW EXPERIENCES DURING PREGNANCY CAN AFFECT THE PHYSIOLOGY AND BEHAVIOR OF HER PROGENY BEFORE AND AFTER BIRTH WHICH MAY CONTRIBUTE TO LONG-TERM HEALTH AND WELFARE PROBLEMS LATER IN LIFE. THE GUT MICROBIAL ENVIRONMENT (MICROBIOTA) HAS BEEN REPORTED TO INFLUENCE HOST PHENOTYPES GREATLY. HOWEVER, THE GUT MICROBIOTA, WHICH GREATLY INFLUENCES THE BRAIN AND IMMUNE SYSTEM AND ULTIMATELY AFFECTS BEHAVIOR AND WELL-BEING, IS OFTEN ABSENT FROM WELFARE ASSESSMENTS. IT HAS BEEN SUGGESTED THAT THE MATERNAL MICROBIOME AND METABOLITES TRANSFERRED PLAY A VITAL ROLE IN PREPARING THE NEONATE FOR OPTIMAL HOST-MICROBE INTERACTIONS INFLUENCING IMMUNE AND BEHAVIOR LATER IN LIFE. HOWEVER, LIMITED DATA EXIST ON THE EFFECTS OF PRENATAL STRESS ONTHE MATERNAL MICROBIOME-IMMUNE AXIS RESPONSIBLE FOR INFLUENCING THE HEALTH AND WELFARE OUTCOMES OF THE PROGENY. INVESTIGATING THE EFFECTS OF MATERNAL STRESS ON THE GUT-BRAIN-IMMUNE AXIS PROVIDES A NOVEL APPROACH TO MEASURING ANIMAL WELFARE; THUS, DATA OBTAINED FROM THESE PROPOSED STUDIES CAN BE USED TO ASSESS AND AMELIORATE POOR WELFARE SYSTEMATICALLY. WE WILL ADDRESS THE FOLLOWING SPECIFIC OBJECTIVES: (A) IDENTIFY THE ROLE OF GUT MICROBES-IMMUNE AXIS IN STRESSED SOWS ON THE COLONIZATION OF PROGENY, (B) CHARACTERIZE THE EFFECTS OF MULTIPLE STRESSORS ON THE MICROBIOTA-BRAIN-IMMUNE AXIS IN PROGENY BORN TO STRESSED SOWS, AND (C) DECIPHER THE MOLECULAR MICROBIOTA SIGNATURES AND GUT-IMMUNE AND BEHAVIORAL PHENOTYPES IMPRINTED ON THE PROGENY IN SUBSEQUENT GENERATIONS. THESE DATA WILL BEGIN TO ADVANCE OUR UNDERSTANDING OF THE MATERNAL MICROBIOME AND STRESS RESPONSIVENESS EFFECTS ON MICROBIAL-BRAIN-IMMUNE SIGNATURES IN THE OFFSPRING THAT MAY INDICATE BETTER HEALTH AND WELL-BEING.