Calf Pneumonia

October 2004

Richard Laven BVetMed MRCVS

NADIS Cattle Disease Focus

Calf Pneumonia – The value of diagnosis

The NADIS data show that the winter rise in calf pneumonia cases begins in October.

As calf pneumonia is an extremely complex disease it’s very often not possible to identify the most important cause (or causes) just by looking at the calves.

Diagnosis of the cause requires laboratory testing. However, it’s not always necessary to get a diagnosis; most modern antibiotics are of similar effectiveness and the most commonly used vaccines cover a wide range of diseases.

Thus it’s important when you decide, with your vet, to get a diagnosis that you’re able to use it and that it’s not just another piece of information of limited use.

Diagnosis of the cause of pneumonia should be undertaken to refine treatment and to develop future prevention strategies. It’s thus important to take the right sample from the right animals.

The right animals
Try to avoid samplings animals that:

1. 
   
   Look different from the rest of the affected group – selecting typical cases to sample the best way identify the primary cause.
   
   
2. 
   
   Have got chronic pneumonia – the initial cause is likely to have long gone in these animals

The best policy is to pick early cases and sample them before you treat them. Getting your vet involved early can save significant amounts of money.

The right samples
Each outbreak is different, work with your vet to decide the best ones for you. The test available are:

1. 
   
   Nasopharyngeal swabs. These are long swabs for sampling the back of the throat. They can be used for bacteriology and virology (particularly IBR). Ocular swabs can also be used to test for IBR, if this is suspected.
   
   
2. 
   
   Paired antibody tests. Two blood samples from affected animals at the beginning of the outbreak and then 14 – 21 days later. At least 6 animals should be tested. A rise in antibodies shows that the virus or bacteria were present on the farm.
   
   
3. 
   
   Lung washes. This is the best test for identifying viruses. However it should be done on early cases only. Results are available within 24 hrs, as opposed to 3 to 4 weeks for paired antibody tests.
   
   
4. 
   
   Post mortem investigation. Where deaths have occurred it is important to get the carcass checked either by your vet or by your local vet lab. However, most calves that die are atypical cases and often have far more changes in the lungs than affected living calves. Thus post mortem examination should not be your sole method of diagnosis.
   
   
5. 
   
   Remember lungworm: Remember that in some cases lungworm may be involved.  In immature animals checking that an appropriate wormer has been used is probably all you need to do. In adults blood samples or faecal samples can confirm exposure or infection respectively (although not all affected adults will excrete lungworm eggs. Lung washing can also be used to identify lungworm infection.

While every effort is made to ensure that the content of this forecast is accurate at the time of publication, NADIS cannot accept responsibility for errors or omissions. All information is general and will need to be adapted in the light of individual farm circumstances in consultation with your veterinary surgeon

Copyright © NADIS 2002