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.