ACROSS SPECIES, EARLY SOCIAL CONTACT HAS A KEY ROLE IN SHAPING LONG-TERM BEHAVIORAL AND PHYSIOLOGICAL RESPONSES, INFLUENCING SOCIAL BEHAVIOR, COGNITION, REPRODUCTIVE DEVELOPMENT, AND IMMUNE FUNCTION. IN THE DAIRY INDUSTRY, THE COMMON PRACTICE OF SOCIALLY ISOLATING CALVES MAY REPRESENT A LOST OPPORTUNITY TO IMPROVE LIFELONG WELFARE AND PERFORMANCE THROUGH SOCIAL ENRICHMENT. GIVEN THE ONGOING PREVALENCE OF INDIVIDUAL HOUSING FOR CALVES AMIDST WELFARE AND SUSTAINABILITY ISSUES CURRENTLY FACING THE DAIRY INDUSTRY, OUR OBJECTIVE IS TO DETERMINE THE IMPACT OF EARLY SOCIAL HOUSING ON LONG-TERM WELL-BEING AND PERFORMANCE OF DAIRY HEIFERS INTO THEIR FIRST LACTATION. OUR SPECIFIC OBJECTIVES ARE DETERMINE HOW EARLY SOCIAL CONTACT MAY SUPPORT 1) LONG-LASTING IMPROVEMENTS IN COGNITION, SOCIAL ABILITY, AND RESILIENCE TO ROUTINE STRESSORS; 2) IMPROVED GROWTH, HEALTH, AND IMMUNE COMPETENCE; AND 3) INCREASED EXPRESSION OF ESTRUS BEHAVIOR AND REDUCED AGE AT PUBERTY. DATA COLLECTION WILL SPAN EARLY LIFE UNTIL POST-CALVING, EVALUATING INDUSTRY-RELEVANT PRE-WEANING HOUSING METHODS, INCLUDING INDIVIDUAL HOUSING, PAIR-HOUSING, AND GROUP-HOUSING. TOWARDS OUR FIRST OBJECTIVE, WE WILL ASSESS BEHAVIORAL DEVELOPMENT, COGNITION, AND RESPONSE TO ROUTINE STRESSORS, INCLUDING REGROUPING AND INTRODUCTION TO THE MILKING PARLOR. TOWARDS OUR SECOND OBJECTIVE, WE WILL MEASURE IMPORTANT PERFORMANCE AND HEALTH OUTCOMES, INCLUDING IMMUNE COMPETENCE ASSESSED BASED ON ASPECTS OF CELL-MEDIATED AND HUMORAL IMMUNITY. TOWARDS OUR THIRD OBJECTIVE, WE WILL DETERMINE AGE AT PUBERTY, EXPRESSION OF ESTRUS BEHAVIOR, AND LACTATION PERFORMANCE. THIS PROJECT WILL BE THE FIRST TO DETERMINE LONG-TERM EFFECTS OF EARLY SOCIAL CONTACT ON CRITICAL BEHAVIOR AND PERFORMANCE OUTCOMES, PROVIDING FUNDAMENTAL STEPS TOWARDS TRANSFORMING CALF MANAGEMENT PRACTICES TO IMPROVE LIFELONG WELFARE AND SUPPORT SUSTAINABILITY OF THE DAIRY INDUSTRY.