책임운영기관 농촌진흥청 국립축산과학원 (로고)

economic losses and adverse impacts on animal welfare. This study aimed to determine the optimal timing for respiratory vaccination in Jersey calves, considering age-related responses and maternal antibody interference. Twenty-five Jersey calves were randomly assigned to three vaccination groups based on timing: Group A (14 and 16 weeks), Group B (16 and 18 weeks), and Group C (18 and 20 weeks). Calves were further divided into subgroups based on their initial Infectious Bovine Rhinotracheitis (IBR) antibody levels. Blood samples were collected at 8, 14, 24, and 52 weeks of age to measure IBR and Bovine Viral Diarrhea (BVD) antibody levels. The results indicated that the vaccination strategy, which considered maternal IBR antibody levels at the time of vaccination, enhanced long-term IBR immunity and influenced BVD immunity. Additionally, calves vaccinated while seronegative for IBR exhibited higher seropositivity at 52 weeks compared to those immunized while seropositive. Our findings suggest that the optimal vaccination strategy for Jersey calves involves primary vaccination between 14 and 18 weeks of age, followed by a booster shot at a two-week interval. Furthermore, low maternal anti-IBR antibody levels at the time of vaccination were associated with increased antibody levels at 52 weeks of age and may influence BVD immunity. These findings could inform the development of more effective vacci nation strategies for Jersey calves, potentially enhancing BRD management and reducing the economic impact on this breed.