Clinical Signs

The main concern with Brucella abortus in cattle is the effect that it has on the reproductive system and resulting abortions:

  • Generally abortions are seen in susceptible, unvaccinated heifers. Most abortions occur after the fifth month of pregnancy.
  • It is common for ‘abortion storms’ to occur in which spontaneous abortions run rampant throughout a herd.
  • Susceptible cows that are introduced to an infected herd also may abort.
  • Sequelae to abortions are retained placentas and subseqent metritis.
Orchitis and epididymitis are occasionally seen in breeding age bulls.  One or both testes may be involved and sterility most commonly results.  The picture here shows orchitis in a pig.
Non-suppurative synovitis is a less common clinical sign seen in cattle.   Hygromas in the carpus are the most common manifestation and Brucella abortus is often isolated from these joints.  Animals with these lesions are not always seropositive.

Brucellosis Menu | Diagnosis