Reducing the risk of pneumonia in calves at turnout

Sarah Higgins MVB MRCVS CertAVP, Ruminant & Equine Veterinary Manager, MSD Animal Health

Respiratory disease is commonly seen in both dairy and suckler calves. Pneumonia is the most significant cause of death in cattle greater than one month of age in Ireland. There are substantial long term implications of respiratory disease on productivity for both dairy heifer and beef calves, with reduced milk yield and reduced average daily gain respectively. Therefore, it is imperative that farmers implement a strategic plan pre-turnout to maximise calves’ immunity in conjunction with minimising infectious pressure.

What causes pneumonia in calves?

It’s a complex interaction between the animal, pathogens (bacteria, viruses and lungworm) and the environment. A primary viral infection can compromise lung defence mechanism. Subsequently, calves are predisposed to bacterial infection of the lower respiratory tract. It is therefore fundamental to monitor calves frequently post turnout to observe for clinical signs of disease. Clinical cases of pneumonia may present with all or some of the following signs.

  • Nasal or ocular discharge increased rate
  • Effort of respiration (panting)
  • Fever (greater than 39.5⁰C)
  • Off-form
  • Poor appetite
  • Coughing

There is a seasonal peak in cases of pneumonia from September to October. However, it is worth noting that the threat of pneumonia is omnipresent. Pneumonia can occur at any stage of the year whether calves are indoors or outdoors.

Why are calves at risk of developing pneumonia at turnout?

There are multiple stressors associated with turnout which include change of diet, change of environment, unfavourable weather conditions and commingling. These stressors negatively impact the calves’ immune system resulting in increased susceptibility to developing disease, notably bovine respiratory disease, of which pneumonia is the main syndrome. Turn out healthy calves only, if possible, on a mild day and maintain concentrate feeding for at least one month, typically 1 kg per animal per day, to mitigate stress.

The changeable nature of the weather is a major predisposing factor for calves to present with pneumonia. A well sheltered paddock is recommended for youngstock at turnout in tandem with a vaccination programme.

Vaccination is a vital component of the control measures to reduce the risk of pneumonia as it enhances immunity by stimulating production of antibodies. Vaccination will reduce infection and clinical signs of pneumonia. Bovilis Bovipast RSP protects against both viral and bacterial agents namely PI3, RSV and provides the broadest protection against Mannheimia haemolytica.

Do these new-born calves vaccinated against RSV and PI3 require further vaccination against pneumonia?

Bovilis INtranasal RSP has a duration of immunity of 12 weeks, thereby providing protection in the early critical high risk first few months of life. However, prior to, or at, turnout this protection may have lapsed. To provide protection against RSV, PI3 and Mannheimia haemolytica, Bovilis Bovipast RSP can be administered. A primary course comprises of two subcutaneous (under the skin) doses four weeks apart, with an onset of immunity of two weeks. Ideally calves should receive the second dose two weeks pre-turnout as the second dose results in an increased antibody titre and thus improved protection. Due to potential time constraints and the timing of turnout, the second dose can be administered post turnout. Ensure to use sterile clean needles and syringe for administration.

Act now to reduce potential losses and contact your veterinary practitioner for further information. Further information is available on