The phone rang ,’ I have a problem its pneumonia and its bad’. The farm in question just had an outbreak of respiratory disease in autumn born calves. They occasionally get pneumonia but this was worse, one calf was quiet bad and there was several in the group blowing (respiratory rates) according to the farmer.
Every time I step out of my jeep my mind starts assessing the situation on any farm. As I approach the shed I’m considering ventilation issues and as I walk into the shed I turn on my senses.
Why? Because when we are looking at any pneumonia problem what we see, smell and hear are all important.
The first thing is to look at is the shed and the calves, is it more than one calf affected could ventilation in the sheds be an issue. Walking into a calf shed smells can be important, it can again tell me if ventilation is a problem. Remember fresh air for calves is extremely important to reduce the risk of pneumonia. We must try provide this fresh air with out allowing draughts in sheds.
Listening for coughing can sometimes indicate the severity of the pneumonia in calves. Anytime I walk into a shed of cattle in the winter my ear will be listening for any increased frequency of coughing.
If I am dealing with a group of calves with pneumonia I must consider is something affecting their immunity that is making them pick up infections. Equally it is important to look to see has something allowed infection levels to get so high that they over whelm the young calves immune systems. Housing can play a massive role in predisposing cattle to pneumonia and should always be assessed but particularly when repeated incidences are occurring.
So after assessing the house we then began examining some of the many sick calves. Most had High temperatures and listening to their lungs very harsh respiratory sounds. It was agreed that almost 70% of one batch of older calves were affected and on further questioning the first symptoms where seen probably late in the week before.
One thing with these dairy calves was they were in the same airspace as the adult cows. This can increase the risk of virus pneumonia in particular. This occurs because freshly calved cows are under stress causing them to shed more viruses around calving. The adult cows may or may not be sick but potentially pose a risk to younger calves.
With individual cases early treatment is important and also the length and choice of antibiotic is an important decision to be made with your vet.
However in a severe outbreak like this we will often begin group treatments because of the severity of the condition. All the affected group were treated and we assessed younger calves and advised to monitor these.
We assessed nutrition and housing and found both to be good.
The farmer asked me the obvious question, what is causing this pneumonia?
My own mind kept telling me that it looked to be viral in the early stages but then progressed onto secondary bacterial pneumonia.
He had plenty of fresh cases so we went and did some nasal swabs on these. This allows us to check for dna of the viruses/bacteria on the swab when we send it to the lab for testing.
The pneumonia was affecting calves 4 weeks+, but on examining some younger calves there was indications of possible virus pneumonia also.
It was agreed I would revisit them the following morning.
On my return the following morning one calf had to be put down while the rest of the batch had responded well to anti-inflammatories and antibiotics. I took the opportunity while there to post mortem the calf that died.I found evidence of a severe chronic bacterial pneumonia on post-mortem. This had done two things it had shown the farmer the severity of the pneumonia but also it indicated to me the problem might have been going on for a while.
In this case we had been using firefighting tactics to respond initially by treating the group. However we also had established that there were more calves due and did not want a repeat of this problem in springtime.
We established that the condition was probably going on for a while and firstly decided in future any symptoms like these would be investigated earlier. Our nasal swabs came back positive for RSV virus and we established a vaccination program in future for young calves. This identification of the virus through diagnostics allows us be much more strategic with our vaccination. We also on further reflection had admitted this was an ongoing issue and alternative accommodation could be provided for calves in a separate airspace away from freshly calved cows as this was likely to be contributing to the problem.
While these severe pneumonia outbreaks are uncommon they do occur! While initially we have to be quiet reactive in our approach I hope this case highlights the importance of quickly switching our focus onto being proactive in any long term controls.