THE GOAL OF THIS PROJECT IS TO DEVELOP AN EFFECTIVE VACCINE AGAINST BOVINE RESPIRATORY SYNCYTIAL VIRUS (BRSV). BRSV CAUSES SEVERE RESPIRATORY DISEASE (INCLUDING FEVER, COUGHING, GASPING AND PNEUMONIA) AND EVEN DEATH IN CALVES. RESPIRATORY DISEASES NOT ONLY CAUSE SIGNIFICANT ECONOMIC LOSSES TO CATTLE FARMERS BUT ALSO ARE A PUBLIC HEALTH CONCERN BECAUSE OF THE RISK OF DEVELOPING ANTIBIOTIC RESISTANT BACTERIA FROM THE USE OF ANTIBIOTICS TO TREAT SECONDARY BACTERIAL INFECTIONS. IT IS ALSO AN ANIMAL WELFARE ISSUE BECAUSE OF THE SUFFERING IT CAUSES TO ANIMALS. AT PRESENT, THERE IS NO SATISFACTORY VACCINE AVAILABLE FOR THE PREVENTION OF BRSV INFECTION. WE WILL DEVELOP AN IMPROVED VACCINE THAT WOULD PROTECT CALVES FROM GETTING THE DISEASES. IN THIS PROJECT AN APATHOGENIC VACCINE STRAIN OF NEWCASTLE DISEASE VIRUS (NDV), A CHICKEN VIRUS, WILL BE USED TO CARRY THE PROTECTIVE ANTIGEN OF BRSV IN MOST EFFECTIVE FORM. THE RECOMBINANT (R) NDV BASED BRSV VACCINE WILL NOT CAUSE ANY DISEASE IN CALVES BUT WILL PRODUCE PROTECTIVE IMMUNE RESPONSE AGAINST BRSV. THE RESULTS OBTAINED FROM THIS STUDY WILL NOT ONLY BENEFIT THE CATTLE INDUSTRY BUT ALSO SHOW IF A SIMILAR VACCINE STRATEGY CAN BE USED FOR OTHER CATTLE DISEASES.THE SPECIFIC OBJECTIVES OF OUR PROJECT ARE:1. CONSTRUCTION, RECOVERY, AND CHARACTERIZATION OF RNDV CONTAINING THE F GENE OF BRSV.2. EVALUATION OF TROPISM, REPLICATION AND IMMUNOGENICITY OF RNDV IN CALVES3. EVALUATION OF PROTECTIVE EFFICACY OF RNDV EXPRESSING BRSV F PROTEIN IN CALVES.