Causes of Bovine Pneumonia

The aetiology of Bovine Pneumonia is multifactorial, stress and infectious agents both play a major role.

Stress in intensive cattle production

Stress is a major predisposing factor to Pneumonia outbreaks.

Transportation over long distances serves as a stressor as it may be associated with:

• Exhaustion
• Starvation
• Dehydration
• Chilling and overheating depending on weather conditions
• Exposure to vehicle exhaust fumes.

Additional stressors on cattle destined for feedlots are:

• Passage through auction markets
• Commingling
• Processing
• Surgical procedures on arrival at the feedlot
• Dusty environmental conditions
• Nutritional stress associated with a change to high-energy rations in the feedlot.

Infectious agents

Mannheimia haemolytica and Pasteurella multocida are consistently isolated from the lungs of sick cattle. These pathogens are associated with a high mortality rate.

Other pathogens that may also be responsible in the aetiology of the disease include:

• Respiratory viruses:- PI-3, RS, IBR, BVD
• Other bacteria e.g. Histophilus somni

Pasteurella multocida
Courtesy of Inst. for Animal Health, Compton, UK