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Bovine Respiratory Disease (BRD)

Bovine Respiratory Disease (BRD)

BRD is the most devastating disease of the US cattle population.

BRD is a general term for respiratory disease in cattle caused by a range of factors, singly or in combination. A major cause of economic losses, BRD affects the lower respiratory tract / lungs (pneumonia) or upper respiratory tract (rhinitis, tracheitis, bronchitis).

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  • Etiology

    BRD is defined as a “disease complex”:

    • It usually is caused by a variety of pathogens, both viral (Bovine Respiratory Syncytial Virus (BRSV), ParaInfluenza 3 (PI3), Adenovirus, Bovine Viral Diarrhea Virus (BVDV), and Infectious Bovine Rhinotracheitis (IBR)) and bacterial (Pasteurella multocida, Mannheimia haemolytica, Histophilus somni, Mycoplasma bovis).
    • Parasitic (lungworm) and fungal (Aspergillus) agents are also pathogens. 
    • These pathogens  interact with one another and the animal’s immune system to produce full-blown disease.
    • Bacterial pathogens apparently cause the acute syndrome by invading the bovine respiratory tract that has been compromised by viral infections, environmental conditions and/or other stress factors.

    Contributing to the disease complex is stress.  Stressors include weaning, changes of feed, variation in ambient temperature and humidity, and weather. 

  • Symptoms

    Clinical signs of BRD  in cattle depend on many factors including  the age of the animal, the causative organism(s) and thestage of the disease.

    General signs:

    • Fever - The connection between BRD and fever is extremely strong. BRD is one of the most common causes of fever - and fever is always one of the earliest signs of the BRD complex.
    • Depression.
    • Lack of appetite.
    • Dullness

    Respiratory signs:

    • Rapid, shallow breathing.
    • Coughing.
      • In early BRD cases, the lungs and airways are generally painful, so the animal will try to clear the airway with mild, tentative, soft coughing.
      • Loud, prominent coughing or “honking” indicates far more chronic, advanced cases, at which point treatment is difficult.
    • Serous (watery), then purulent (pussy), and/or bloody nasal and eye discharge.
    • Salivation.
  • Diagnosis

    Diagnosis may be made on clinical signs and epidemiology, but additional examinations are often needed (e.g., tracheal washings, nasopharyngeal swabs, blood samples, post-mortem examinations).

  • Treatment

    Treatment should always be specifically targeted to the disease and the symptoms (anti-infectious agents(Antibiotics and Sulfas), antiparasiticides, non steroidal anti-inflammatories, bronchodilators, mucolytics, oral rehydration fluids) in consultation with the attending veterinarian.

  • Prevention

    The key to preventing respiratory disease is to reduce stress and to vaccinate against viruses and bacteria that cause disease.

    • Vaccination with biological products targeting the viral and bacterial pathogens.
    • Appropriate use of antibiotics labeled for control of BRD
    • Good cattle handling and stress reduction
    • Minimize exposure to environmental conditions that contribute to disease, such as dust, crowding, fumes (proper ventilation is a key - especially with dairy facilities).
    • Provide adequate rest, feed and water (especially after shipping).
    • Make sure animals receive adequate levels of essential  nutrients such as vitamins and minerals.
    • Nutritional soundness also helps prevent disease and improves immune function.
    • Handle animals with care.  Use low stress handling techniques.
    • Reduce and/or minimize pen movements.
    • Make sure bedding is clean and dry .
    • Keep animals as clean and dry as possible.
    • Avoid overcrowding.
    • Maintain good housing and ventilation.
    • Minimize heat stress.
    • Make sure animals receive the right deworming program in areas affected by lungworm.
    • Effective colostrum management
  • Economic Impact
    • In the US beef industry, BRD continues to be the primary cause of morbidity and mortality in feedlots contributing to losses in performance, carcass quality and health. 
    • In the US dairy industry respiratory disease continues to play a major role in death losses in weaned calves and morbidity due to BRD affects survivability and reduced dairy performance later in life.
    • Economic losses include death loss, decreased weight gain, and additional labor and treatment costs.