cows in a dusty pen walking right

Causes and Risk Factors

A general term for respiratory disease in cattle, BRD is often called a “disease complex” because many factors can contribute to its development and progression, including:

  • Stress from weaning, castration, dehorning, transport, commingling, poor ventilation and overcrowding can compromise an animal’s immune system, making it vulnerable to viruses and bacteria.
  • Viruses such as bovine respiratory syncytial virus (BRSV), parainfluenza 3 (PI3), bovine viral diarrhea (BVD) virus, infectious bovine rhinotracheitis (IBR) virus and bovine coronavirus (BCV) can further compromise the respiratory tract.
  • Bacteria including Pasteurella multocida, Mannheimia haemolytica, Histophilus somni and Mycoplasma bovis may exacerbate the problem.
  • Parasites and fungi such as lungworm and Aspergillus also can damage the respiratory system.
  • Weather or temperature fluctuations can increase the risk of BRD as well.


The signs of BRD may vary depending on the animal’s age, the organisms involved and the severity of disease. BRD can affect the upper respiratory tract, causing inflammation in the nasal passages, trachea and bronchi, the airways leading to the lungs. Pathogens also can invade the lower respiratory tract, or the lungs, causing pneumonia. Calves may stand with ears drooping, heads and necks extended and their backs bowed in an effort to breathe. Other signs include:

  • Fever
  • Coughing
  • Rapid, shallow and/or noisy breathing
  • Nasal and/or eye discharge
  • Loss of appetite
  • Depression
  • Death
side profile of a cow


A presumptive diagnosis of BRD is often made based on signs, the physical exam and disease incidence in the herd. Early detection is important so affected calves can be isolated in the sick pen. In many cases, an antimicrobial may be administered before disease-causing bacteria are identified to get the animal on the road to recovery as soon as possible.

An accurate diagnosis is important because many conditions have similar signs and can be mistaken for BRD, including:

  • Allergic pneumonia and nasal inflammation
  • Pulmonary edema/heart failure
  • Pleuritis (inflammation of the lung lining)
  • Pulmonary fibrosis (damaged or scarred lung tissue)
  • Lungworms

Get the correct diagnosis for BRD. (click to learn more)

cows standing next to a fence in a field backlit by the sun

BRD Prevention

To help prevent BRD, work with your veterinarian to build a comprehensive program that includes:

  • Effective colostrum management to help support immune function
  • Vaccination with products that target the most likely viruses and bacteria
  • Deworming, especially for areas affected by lungworm
  • Proper nutrition including a balanced ration with proper levels of vitamins and minerals
  • Other preconditioning strategies such as weaning, castrating and dehorning calves at least 30 days before shipping
  • Rest after shipping, keeping food and water within easy access
  • Avoidance of commingling animals from different sources
  • Stress reduction by minimizing animal handling, pen movements and overcrowding
  • Proper ventilation to reduce dust and fumes and reduce heat stress when possible
  • Good hygiene including clean, dry bedding
workers tending to a cow locked in a machine

BRD Treatment

Your veterinarian also can recommend effective antimicrobials for BRD control on arrival and BRD treatment. To ensure that antimicrobials are used responsibly, your veterinarian will consider the product’s:

  • Spectrum of activity
  • Mode of action
  • Duration of action
  • Efficacy
  • Withdrawal period

BRD Insights

Zoetis Technical Services veterinarians can provide you with expert advice and tips to help you manage BRD more effectively.



A good on-arrival program that includes vaccinating and proactively addressing environmental challenges, helped one stocker keep bovine respiratory disease (BRD) in check.

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