Calf diphtheria

Attention! This is a potentially life-threatening condition for your Cow. Time is of the essence, contact your veterinarian immediately.

Calf Diphtheria

Laryngeal Necrobacillosis, Necrobacillosis

Calf diphtheria is a necrotic laryngitis that occurs in young calves (5 weeks old to 24 months old) worldwide, caused by an infection of the laryngeal tissue with Fusobacterium necrophorum bacterium. The condition can be acute or chronic and occurs sporadically year round but is most prevalent in the fall and winter months. It is thought to occur secondary due to prior laryngeal trauma or upper respiratory viral infection, often infectious bovine rhinotracheitis (IBR) or bovine respiratory syncytial virus (BRSV).

F. necrophorum is a normal inhabitant of healthy cattle but is opportunistic and when it multiples it causes the development of lesions throughout the calf's larynx which causes them painful respiratory distress and associated signs which differ depending on the severity and stage of the disease.


Unilateral facial swelling over the cheek area
Difficulty breathing (extending neck and head outward and open mouth breathing)
Painful coughing
Increased noise
Nasal discharge
Foul odor from mouth
Reluctance to eat


  • History
  • Clinical signs
  • Physical exam
  • Laboratory testing
  • Necropsy


NSAIDs (flunixin meglumine) + Antibiotics (oxytetracycline, procaine penicillin G, sulfonamide, or tylosin)

Article Reference

Risk Factors

  • Confining calves in feedlots




  • Fusobacterium necrophorum

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