As calf sheds begin to fill on farms this spring, pneumonia can begin to become an issue on many dairy farms.

Pneumonia and scour are the two biggest killers of young calves, so prevention of these illnesses should be of high priority.

Pneumonia is the result of a complex interaction between viral and bacterial pathogens, environmental stress factors, and the animal’s own resilience to disease.

Some factors that increase the risk of an pneumonia outbreaks are:

  • Low environmental temperatures;
  • High humidity;
  • Poor ventilation;
  • Draughts;
  • Overcrowding;
  • Poor nutritional status.

Infectious agents involved in causing pneumonia include: mannheimia haemolytica; haemophilus somnus; infectious bovine rhinotracheitis (IBR); bovine respiratory syncytial virus (RSV); parainfluenza III virus (PI3), along with many other bacteria and mycoplasma species and viruses.


Ensuring that calves get sufficient levels of high quality colostrum at birth is a key part of preventing cases.

You should ensure that the shed has effective ventilation and that there are no draughts at calf level, as the environment in which calves are living in has a significant impact on them.

Avoid overcrowding of sheds and pens and mixing different aged calves.

Each calf requires 1.5m² of lying space/calf and an air space of 7m³/calf.

Bedding shortages are an issue on many farms, but not keeping on top of the bedding could be detrimental to calf health.

The ‘knee test’ should be used to check bedding and replace once it has become too damaged.

To perform a knee test, place your knee on the straw and if it is damp, the bedding needs to be changed; if it is are dry, the bedding is suitable.

Many of the factors that increase the risk of cases can be linked to the bedding, so it is vital that close attention is payed.