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Paratuberculosis vaccine in a large dairy herd
1Central Veterinary Institute, Budapest, Hungary.
Acta Veterinaria Hungarica
|January 1, 1992
Summary
Vaccinating young calves against Mycobacterium paratuberculosis significantly reduced fecal shedding of the bacteria. While initial antibody responses increased, long-term monitoring indicated a decrease in seropositive animals and antibody titers.
Area of Science:
- Veterinary Immunology
- Bovine Infectious Diseases
- Mycobacterial Infections
Background:
- Mycobacterium paratuberculosis causes Johne's disease in cattle, leading to significant economic losses in dairy herds.
- Effective control strategies for paratuberculosis are crucial for herd health and productivity.
- Vaccination is a potential tool to mitigate the impact of Mycobacterium paratuberculosis infection.
Purpose of the Study:
- To evaluate the efficacy of a heat-killed, oil-adjuvanted bacterin against Mycobacterium paratuberculosis in young dairy calves.
- To assess the impact of vaccination on fecal shedding, serological responses, and overall infection dynamics over a five-year period.
Main Methods:
- A five-year field study involving 866 vaccinated calves and 721 (bull) + 379 (female) unvaccinated control calves on a 500-cow dairy farm.
- Regular testing of vaccinated calves using fecal microscopy, bacteriology, and serology (complement fixation test [CFT] and agar gel immunodiffusion [AGID]) at multiple time points.
- Trend analyses were employed to evaluate the vaccination outcomes.
Main Results:
- Vaccination significantly reduced fecal shedding of Mycobacterium paratuberculosis, with only 9 positive samples out of 612 in the final six months.
- Serological tests showed an initial increase in seropositive animals and antibody titers (CFT and AGID) during the first three years.
- A subsequent decrease in both seropositive animals and CFT titers was observed in the later stages of the experiment.
Conclusions:
- The heat-killed, oil-adjuvated bacterin demonstrated a strong capacity to reduce fecal shedding of Mycobacterium paratuberculosis in young dairy calves.
- The observed pattern of serological responses suggests a complex interaction between vaccination, infection pressure, and immune status over time.
- Further research is warranted to fully elucidate the long-term protective effects and optimal vaccination strategies against paratuberculosis.