Category:Forestomach - Inflammatory Pathology

Granulomatous Inflammation

Traumatic Reticulitis

Mucormycosis

• Mucor, a fungi, invades the rumen wall, e.g. after damage caused by rumenal acidosis.
• Produces chronic ongoing granulomatous rumenitis.
• Difficult to diagnose in life.
• May produce pain and poor growth
• Infective process may penetrate wall and produce peritonitis.

Pathology

Gross

• Thickening and ulceration of mucosal surface of rumen.
  • Feels like thick leather.
• Rumen wall becomes fibrosed.

Histological

• Classical granulomatous inflammation
  • May have giant cells in addition to sheets of macrophages.
• Can visualise fungal hyphae in tissue using special stains (PAS),
  • Often grow along blood vessels.
    • May cause thrombosis of small blood vessels, leading to further necrosis (infarction) of rumen wall.

Neutrophilic Inflammation

Rumenitis

• 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.