Article Text

Farm Animal Practice
Sporadic milk drop in dairy cows: a new causal agent to consider?
  1. Roger Gunning

    Roger Gunning graduated from the Royal Veterinary College in 1969, having previously gained a national diploma in agriculture. He spent nine years in agricultural (mainly dairy) practice and 22 years in the Veterinary Investigation Service (now the Veterinary Laboratories Agency [VLA]), including 14 years at VLA Langford. He holds an MSc in veterinary pathology.


THE term ‘milk drop’ is now in common usage to describe an acute fall in the milk yield of an individual cow or group of cows, often in the absence of other conspicuous clinical signs. An epidemic of milk drop may follow the introduction of a specific infectious agent, most notably Leptospira hardjo or infectious bovine rhinotracheitis virus, into an immunologically naive herd. These agents may also be responsible for sporadic cases in herds where some degree of immunity already exists. Epidemic or sporadic milk drop may also have a non-infectious cause, such as acetonaemia or ruminal acidosis. The list of potential infectious and non-infectious causes of milk drop is seemingly endless but, in most cases, the fall in milk yield will be accompanied by at least one other obvious clinical sign, such as diarrhoea or respiratory distress. Careful clinical examination, supported where necessary by ancillary laboratory tests, is therefore required to establish a clear-cut diagnosis. This article discusses recent evidence that has pinpointed influenza A viruses as being possible causes of sporadic milk drop syndrome in dairy cows.

Statistics from

Request permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.