Calf Pneumonia

Calf pneumonia, also known as Bovine Respiratory Disease (BRD), is a multi-factorial disease represented by viral, bacterial and environmental factors that can act together, affecting the young calves up to about five months.

What causes Pneumonia?
The bacterial pathogens associated causing  pneumonia are represented by: Mycoplasma bovis, Mannheimia haemolytica, Pasterurella multocida and Histophilus somni.

The viral agents are: bovine respiratory syncytial virus (BRSV), parainfluenza-3 virus (PI-3) and infectious bovine rhinotracheitis (IBR).

The environmental factors are high humidity, low temperature, stress, poor access to feed or changes in diet (weaning), poor ventilation, overstocking.

How to spot the sick calves?
In the early stages the signs could be quite hard to notice. The first sign is the presence of fever >39.5 °C. Other signs include dullness, unwilling to feed, increased respiratory rate, nasal discharge (clear and watery that will become thick as the disease progresses), coughing, weeping eyes, separation from the group.


Prevention consists of trying to support the calf’s immune system; this can be achieved through good management practices:

  • Colostrum management – a calf should have 10% of its body weight of colostrum in the first 12 hrs.
  • Good ventilation – wind speed should be < 1m/s at calf level. You can measure that using smoke pellets. Smoke should clear up in 2-3 min.
  • Low humidity – dry bedding changed frequently.
  • Good hygiene – cleaning and disinfections of pens. Work with younger animals before the older ones.
  • Vaccination.
  • Low stock density – not less than 4 m2 per animal (for animals less than 149kg).
  • Ensuring age groups are not mixed

Vaccines are available that will enhance protection against the common viral and some of the bacterial causes of pneumonia.
It is important that vaccines are administered prior to high-risk periods to ensure that there is sufficient time for animals to develop effective immunity.