Vet Lab Agency’s Farmfile data show that 63% of farms find two or more bugs may be causing mastitis problems in the course of a year.

The data collated information from farms sending a number of samples for bacteriology over a 12-month period, said Schering Plough’s Stewart Hall.

On 40% of farms there were three or four bugs identified in samples and five or more on 5%.

“But we always talk about having a problem with one particular bug.

The data show there is often a mix of bugs on the same farm.”

When deciding treatments it is best to look at a number of test results through the year to see what is going on.

Knowing whether gram negative, gram positive or both types of bacteria are present will help the farm’s vet advise the right dry cow therapy, said Mr Hall.