**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** ABOUT 25% OF YOUNG BREEDING FEMALE PIGS (GILTS) NEVER PRODUCE A LITTER OF PIGLETS, RESULTING IN A CONSIDERABLE ECONOMIC COST TO THE FARM AND OVERALL PORK PRODUCTION. GILTS THAT ATTAIN PUBERTY AT AN EARLY AGE ARE MORE LIKELY TO STAY IN THE BREEDING HERD AND HAVE HIGHER QUALITY PIGLETS, BUT THE ABILITY TO PREDICT THESE EARLY-PUBERTY GILTS ON THE FARM IS NOT CURRENTLY POSSIBLE. AT PRESENT, BY THE TIME A GILT IS IDENTIFIED AS NOT SUITABLE FOR BREEDING SHE IS ABOVE THE TARGET WEIGHT FOR A MARKET HOG AND THUS SOLD AT A LOWER PRICE REPRESENTING ANOTHER NEGATIVE ECONOMIC IMPACT. BIOMARKERS THAT CAN BE EASILY ASSESSED IN THE BARN THAT WOULD IDENTIFY GILTS THAT ATTAIN PUBERTY AT AN EARLY AGE WOULD SUBSTANTIALLY DECREASE GILT DEVELOPMENT COSTS AND IMPROVE OVERALL PIGLET QUALITY. THE OBJECTIVE OF THIS PROJECT IS TO DEVELOP PREDICTIVE BIOMARKERS BASED ON CHANGES IN VAGINAL EPITHELIUM ASSOCIATED WITH PREGNANCY SUCCESS TO PREDICT AGE AT PUBERTY IN GILTS. IT IS EXPECTED THAT THESE BIOMARKERS CAN BE DEVELOPED INTO A TOOL FOR USE IN COMMERCIAL SWINE BARNS TO IDENTIFY GILTS MORE LIKELY TO ACHIEVE HIGH REPRODUCTIVE SUCCESS. APPLICATION OF AN ON-FARM TOOL IS EXPECTED TO INCREASE SOW HERD RETENTION RATES AND IMPROVE THE QUALITY OF PIGLETS RESULTING IN A POSITIVE ECONOMIC IMPACT ON PORK PRODUCTION.