Etiology of Bovine Respiratory Disease Complex (BRDC)

Many different factors pre-dispose cattle to BRD, viruses and bacteria as well as stress and transport are part of the etiology. BRD is a multifactorial disease also known as “Shipping fever” or “Crowding disease”.

Factors predisposing cattle to BRD

Factors predisposing to BRD in cattle

Non infectious causes

Infectious agents

Animal factors

Viruses

Respiration volume
Breed -certain breeds have inadequate temperature control mechanisms
Age - younger cattle are more susceptible

respiratory syncytial virus
parainfluenza virus
infectious bovine rhinotracheitis virus

Climate

Bacteria

Temperature / humidity
Ventilation / air flow

Mannheimia haemolytica
Pasteurella multocida

 

Mycoplasma

Management

Parasites

Housing density
Poorly designed housing can have a negative effect on air flow.

Lungworm

Stress factors  
Weaning
Transport
Handling
Mixing		 

Animal factors e.g  respiration volume, environmental factors such as climate (in the stable or environmental) and management parameters (animal density and stress factors such as weaning and transport) all play a role. These factors do not directly cause disease, but have a negative effect on the resistance of the animal against contagious agents and thus facilitate the clinical manifestation of respiratory infections.

The infectious causes listed above are the most frequently isolated from cases of BRD, other viruses and bacteria can be involved but are less frequently isolated.

feedlot

Feedlot cattle