Neutrophilic inflammation

  • Opportunistic pathogens take advantage of acidotic lesions and other disturbances of rumen flora.
    • e.g. F. necrophorum, fungi
    • Infection with Mucor gives mucormycosis- chronic ongoing granulomatous rumenitis.
    • Also agents which cause lesions in other areas of tract e.g. BVDV, actinobacillosis.

Pathology

Gross
  • Multiple, dark red areas of swollen papillae, mainly in ventral sac and pillars.
Histological
  • Coagulative necrosis of papillae
  • Marked neutrophil infiltrate
  • Serofibrinous exudate
  • Thromboembolic spread to form areas of coagulative necrosis and abscesses in liver.