** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** METRITIS IS ONE OF THE MOST COMMON DISEASES IN DAIRY COWS CAUSED BY INFECTION OF THE UTERUS WITH MULTIPLE BACTERIA AFTER GIVING BIRTH. AN AVERAGE INCIDENCE OF BOVINE METRITIS IS ABOUT 20% IN A HERD, AND IT CAN REACH UP TO 47%. TO TREAT METRITIS, ANTIBIOTICS HAVE LONG BEEN USED IN US DAIRY FARMS, DESPITE GROWING CONCERNS ABOUT ANTIBIOTIC RESISTANCE AND THE FACT THAT THE SUCCESS RATE FOR ANTIBIOTIC THERAPY IS LESS THAN 75%. THEREFORE, DEVELOPMENT OF EFFECTIVE ALTERNATIVE THERAPIES FOR BOVINE METRITIS IS URGENTLY NEEDED. OUR LONG-TERM GOAL IS TO DEVELOP A SAFE AND EFFECTIVE ALTERNATIVE TO ANTIBIOTICS FOR THE TREATMENT OF BOVINE METRITIS. OUR HYPOTHESIS IS THAT CHITOSAN MICROPARTICLES ENGINEERED IN THIS WORK WILL EFFECTIVELY TARGET THE INFECTED UTERUS, LEADING TO RESOLUTION OF METRITIS. TO ATTAIN OUR GOAL, OUR SPECIFIC AIMS ARE TO (1) DEVELOP CHITOSAN MICROPARTICLES THAT SPECIFICALLY ELIMINATE UTERINE PATHOGENS AND REGULATE INFLAMMATION, AND (2) DETERMINE EFFECTIVENESS OF CHITOSAN MICROPARTICLES FOR TREATMENT OF METRITIS IN THE LABORATORY AS WELL AS FIELD APPLICATION. UPON COMPLETION OF THESE AIMS, WE EXPECT OUR CONTRIBUTION TO BE THE DEVELOPMENT OF EFFECTIVE ALTERNATIVES FOR TREATMENT OF BOVINE METRITIS AND A PATENT APPLICATION. THESE RESULTS ARE EXPECTED TO HAVE POSITIVE IMPACTS ON ANIMALS BY IMPROVING THEIR HEALTH AND WELFARE, ON STAKEHOLDERS BY INCREASING CURE RATE AND FARM PROFITABILITY, AND ON THE PUBLIC BY REDUCING USE OF ANTIBIOTICS AND IMPROVING FOOD SAFETY.