We were recently called to look at two cows which had “gone down in the milk”. Examination of the cows revealed high temperatures with a slight watery nasal discharge. This was the second such incident the farmer had found recently.

The herd is already being vaccinated for IBR, which sometimes can give a similar clinical picture. In order to rule out IBR and try to determine a cause for these episiodic bouts of milk drop associated with fever, we took some blood samples to test for a number of diseases.

These cases are often suggestive of tick borne fever (TBF). The cows were therefore treated with antibiotics and anti-inflammatories. The blood samples were tested for the presence of TBF and the test showed the presence of high quantities of circulating anaplasma phagocytophilum, ie the organism responsible for TBF.

The cow’s temperature was back to normal the next day. However, she appeared a little jaundiced. Another blood test revealed that she was suffering from anaemia, which is commonly associated with TBF. This can mean that cows may be slow to recover while the blood count comes back to normal, even though treatment has been succesful.

TBF is carried by ticks which then infect cattle and sheep. It can often be a problem on farms where tick activity is high. Bought-in animals are particularly susceptible and may suffer from infection shortly after being put on affected pasture.

Prevention of the disease is difficult on affected farms. However, efforts should be made to reduce the challenge from ticks.

Pasture management, ie preventing access to long, overgrown patches of grass, is helpful. The use of products effective against ticks may also help. However, it is likely that they would need to be used repeatedly in order to be effective.

John Gilmore is a practising vet and managing director at FarmLab Diagnostics, an animal health testing laboratory www.farmlab.ie.