Shipping Fever Pneumonia

Shipping fever pneumonia is a respiratory disease of cattle of multifactorial etiology with Mannheimia haemolytica and, less commonly, Pasteurella multocida or Histophilus somni (Histophilosis : Introduction), being the important infectious agents involved. Shipping fever pneumonia is associated with the assembly into feedlots of large groups of calves from diverse geographic, nutritional, and genetic backgrounds. Disease is typically seen in feeder calves 7-10 days after assembly in a feedlot. Morbidity can approach 35%; mortality is 5-10%.

The pathogenesis of shipping fever pneumonia involves stress factors, with or without viral infection, interacting to suppress host defense mechanisms, which allows the proliferation of commensal bacteria in the upper respiratory tract. Subsequently, these bacteria colonize the lower respiratory tract and cause a bronchopneumonia with a cranioventral distribution in the lung. Multiple stress factors are believed to contribute to the suppression of host defense mechanisms. Transportation over long distances serves as a stressor; it may be associated with exhaustion, starvation, dehydration, chilling and overheating depending on weather conditions, and exposure to vehicle exhaust fumes. Additional stressors include passage through auction markets; commingling, processing, and surgical procedures on arrival at the feedlot; dusty environmental conditions; and nutritional stress associated with a change to high-energy rations in the feedlot.

Diagnosis

Shipping fever pneumonia is a respiratory disease of cattle of multifactorial etiology with Mannheimia haemolytica and, less commonly, Pasteurella multocida or Histophilus somni (Histophilosis : Introduction), being the important infectious agents involved. Shipping fever pneumonia is associated with the assembly into feedlots of large groups of calves from diverse geographic, nutritional, and genetic backgrounds. Disease is typically seen in feeder calves 7-10 days after assembly in a feedlot. Morbidity can approach 35%; mortality is 5-10%.