Infection is caused by exposure to Leptospira Hardjo and it is common in cattle herds worldwide. It can cause abortions, infertility, milk drop and mastitis. The agent is shed in the urine of animals following exposure to infection and is also present in abortion products. The time that shedding lasts can be very variable from days to months or even years. Infection usually occurs as a result of urine splashing onto the mouth, nose or eyes of cattle. Urine contaminated water (e.g. pools or water courses) in fields that cattle drink from can act as a reservoir of infection. Abortions can result and it can be a few weeks after exposure before this happens. Leptospirosis can also cause milk drop, a change in the appearance of the milk and a “flabby bag” type of mastitis. It can also be infectious to humans and the highest risk would be from urine splashes in the milking parlour. Many dairy herds are vaccinated against leptospirosis to reduce the risk to humans as well as to the cows.
Sheep can carry leptospirosis so can be a risk to cattle if they are co-grazing or if cattle graze fields shortly after sheep have been removed. Certain antibiotics may help reduce or eliminate carriage from the kidneys of cattle. Vaccination is used widely to aid in the control.
Herds can be tested to gain Leptospirosis Accredited or Leptospirosis Monitored Free status.