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Brucellosis in heifers weaned from seropositive dams
Journal of the American Veterinary Medical Association
|September 1, 1986
Summary
Heifers born to dams positive for brucellosis showed no reduction in pregnancy or calf production. However, persistent Brucella abortus infection occurred in 2 heifers, with higher frequency in vaccinated ones.
Area of Science:
- Veterinary Medicine
- Infectious Diseases
- Bovine Reproduction
Background:
- Brucellosis is a significant concern in cattle, impacting herd health and productivity.
- Understanding transmission and persistence of Brucella abortus in offspring is crucial for disease control.
- Previous studies highlight the challenges in eradicating brucellosis from breeding herds.
Purpose of the Study:
- To investigate the reproductive performance of heifers born from Brucella abortus-seropositive dams.
- To determine the incidence of persistent Brucella abortus infection in these heifers.
- To assess the influence of vaccination on infection persistence.
Main Methods:
- Fifty-six heifers from Brucella-positive dams were monitored.
- Reproductive outcomes (pregnancy, calf production) were assessed.
- Parturient heifers were tested for persistent Brucella abortus infection, with vaccination status recorded.
Main Results:
- Heifers exhibited normal pregnancy rates and viable calf production.
- Persistent Brucella abortus infection was detected in 2 out of 37 parturient heifers.
- Infection occurred in 1/10 vaccinated heifers versus 1/27 non-vaccinated heifers.
- Persistently infected heifers displayed atypical serological patterns.
Conclusions:
- Offspring from Brucella-positive dams can achieve normal reproductive success.
- Persistent Brucella abortus infection is possible in heifers, albeit at a low frequency.
- Vaccination with Strain 19 may be associated with a higher frequency of persistent infection in this context.