Pneumonia in calves is a multifactorial disease, meaning that besides infectious agents such as viruses and bacteria, a multitude of environmental and management factors and their interactions are responsible for the outbreak of disease.
Any kind of stress will reduce the ability of the immune system to fight infection. Common stressors in the autumn include weaning, dehorning, castrating, transport, and housing.
Pneumonia is typically started by viruses, including:
- Respiratory syncytial virus (RSV);
- Parainfluenza type 3 (Pi3) virus; and
- Infectious bovine rhinotracheitis (IBR) virus.
Severity can be increased by secondary bacterial infections.
Mycoplasma bovis can cause pneumonia in calves from a young age to older weaned calves. It can cause pneumonia on its own or following a primary viral infection.
In Ireland, Mycoplasma bovis was involved in approximately one in seven cases of death following pneumonia according to recent post-mortem findings.
Mycoplasma bovis can also live in the nose of apparently healthy cattle without causing harm, only becoming an issue if it enters the lungs.
Pneumonia in calves
Pneumonia is the most common cause of death and poor performance in young cattle from weaning to 10 months of age. Notwithstanding death, pneumonia is a very costly disease.
The impact of respiratory disease can result in average daily liveweight gains (DLWG) reduced by up to 200 g/day. Over a 10-month finishing period this mounts up to 61kg reduction in DLWG and it therefore takes up to two months longer to finish an animal which previously suffered a case of pneumonia.
Other costs include poorer carcass classification at slaughter, increased labour and higher vet costs as well as increased antibiotic usage on farm.
Pre-Housing Dose (PHD)
All parasites have a negative effect on the cattle’s immune system and lungworm in particular can damage the lungs and increase the risk and severity of pneumonia.
Treatment for lungworm four to five weeks ahead of housing with a persistent dose such as Cydectin or Dectomax allows time for dead worms to be coughed up and for the lungs to repair and heal from the damage caused by the lungworm.
The benefit of this PHD is that all the worms can be removed from the animal, and the lungs can fully recover from the damage that the worms inflicted while they are still out in clean fresh air.
When they are housed, they will have a clean, healthy set of lungs to combat the dust and viral infections they will encounter in the shed.
Cydectin and Dectomax offer persistency against re-infection by stomach worms (Ostertagia) and lungworm (Dictyocaulus) of five weeks from a single dose. Therefore, animals treated with either Cydectin or Dectomax 5 weeks before housing will not need to receive another dose at housing.
To find out more about the benefits of the PHD, check out the following video.
When worming stock, farmers should be consider the following;
- Weigh animals and dose to the heavier weight (if the weights are similar);
- Check dosing guns are calibrated;
- Check the wormer you are using is within date and has been stored correctly;
- Ensure you are using the product within its shelf-life after first opening as this can differ between brands;
- Make sure your equipment is fit for purpose;
- Check how you apply it (i.e. pour-on subcutaneous injection);
- Buy your products ahead of the housing season so you are well prepared.
Tips for successful vaccination
Vaccines take time to provide sufficient protective cover. This can vary from five days to six weeks, so farmers should plan to use vaccines well in advance of when animals need to be protected.
For home-bred animals an injectable solution might be suitable as farmers can plan to start the vaccination course one month ahead of housing.
Rispoval 2 provides protection for RSV and Pi3, two common causes of pneumonia in Ireland. It is a live vaccine and requires two injections three to four weeks apart. Rispoval 2 protects calves for up to six months against RSV.
Where a quicker onset of immunity is required, for instance close to housing or in bought-in animals, a single dose of Rispoval RS+Pi3 IntraNasal provides rapid onset of immunity against RSV and Pi3.
Rispoval IBR-Marker live can be given either intranasally or intramuscularly and protects calves for IBR for up to six months.
Farmers should talk to their vet now about treating their first and second season grazers with a PHD and autumn vaccination.
For more information on a pre-housing dose, click here. For more information on Rispoval, click here.
