INCREASED LITTER SIZE OF PIGS IN COMMERCIAL BREEDING HERDS HAS RESULTED IN A GREATER NUMBER LIGHTER WEIGHT PIGLETS AT BIRTH WITH COMPRISED HEALTH AND SURVIVABILITY DUE TO THE INCREASED FETAL CROWDING DURING GESTATION. ESTABLISHING THE FUNDAMENTAL ROLES OF CONCEPTUS- AND UTERINE-SECRETED FACTORS IS AN ESSENTIAL STEP TO DEVELOP STRATEGIES TO INCREASE PLACENTAL AND FETAL GROWTH TO IMPROVE OVERALL HEALTH AND SURVIVABILITY OF PIGLETS BEFORE AND AFTER BIRTH. STUDIES WILL TEST THE HYPOTHESIS THAT SPECIFIC EMBRYONIC GENES (AROMATASE, ESTROGEN RECEPTOR AND INTERFERONS) ARE CRITICAL FOR PLACENTAL DEVELOPMENT AND GROWTH TO TRANSFER NUTRIENTS ESSENTIAL TO FETAL GROWTH THROUGHOUT GESTATION. OUR OBJECTIVE IS TO UTILIZE GENE EDITING TECHNOLOGY TO KNOCKOUT SPECIFIC EMBRYONIC GENES TO DETERMINE THEIR ROLE IN EARLY EMBRYONIC DEVELOPMENT AND SURVIVAL. RESEARCH IS EXPECTED TO PROVIDE CLEAR INFORMATION ON THE ROLE OF SPECIFIC EMBRYONIC GENES THAT REGULATE PLACENTAL DEVELOPMENT AND FETAL GROWTH. FUNDAMENTAL KNOWLEDGE GAINED FROM THE RESEARCH WILL BE USED TO DETERMINE THE DIRECTION AND FOCUS OF SUBSEQUENT TRANSLATIONAL RESEARCH TO IMPROVE REPRODUCTIVE EFFICIENCY OF PIGS AND THUS OVERALL PROFITABILITY OF SWINE PRODUCTION ENTERPRISES.