Salmonella risk in dairy herds begins to peak over the autumn
Before I started this article, I quickly opened my emails to see a lab result from an aborted calf we had sent in to be tested.
It had come back as positive for salmonella Dublin and this was the cause of the abortion. This is the second case I have identified in the last six weeks. It is not surprising, as autumn time tends to see the beginning of the peak risk time for salmonella abortions.
I also have had a huge amount of questions from dairy clients recently about positive results on their bulk milk screening tests for salmonella. Questions about how worried should they be and should they vaccinate their cows. This is a discussion each farmer must have with their own vet and decide based on risk about vaccination. Where it has been diagnosed on an abortion there is no discussion the vaccine must be used.
Salmonella is a significant disease in Irish dairy farms, and testing indicates it has a high prevalence - meaning it has been identified in a number of herds even though they aren't showing any clinical signs.
The reality, in practice, for me has been the number one disease I have seen associated with the infection in adult cows is abortion caused by a species of salmonella Dublin.
Followed by some herds getting enteritis or scours often caused by S.Dublin or on some occasions S.thphimurium. In calves it tends to cause septicaemias, which can present as calves with high temperatures being sick stiff and sore.
It can also cause scour in calves and a number of other conditions. So, the big question for farmers is 'I have none of these signs at the moment but my bulk screening test says I have salmonella positive antibodies'.
It can be confusing and I have to admit for many farmers frightening that this disease might be lurking in the herd. So to answer the question I have to explain what the test means.