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These spiral bacteria are common causes of disease in cattle. Infection is associated with milk drop syndrome, abortion, weak calves and infertility. Leptospirosis can spread from cattle to man, causing flu-like symptoms and severe headaches (Weils disease).

In the UK the most common bacteria is Leptospira borgpetersenii serovar hardjo. Probably around 60% of herds in the UK have been exposed to leptospirosis.

Clinical Signs

1. Milk drop syndrome

Sudden large drop in milk production (in some cows it may stop altogether)
All four quarters are affected. The udder is usually soft and flabby and the milk is colostrum-like, with a high cell count but no bacteria.
Affected cows may have a high temperature
Milk drop usually lasts around six days. In some outbreaks 50% of the herd may be affected severely depressing milk production.

2. Abortion

Unlike milk drop which occurs very soon after infection, abortion occurs  4 to 12 weeks afterwards.
Most cases of abortion occur in the second half of pregnancy.
Their is an increased incidence of abortions in the spring time as this is the main season of transmission for Lepto.
Infection close to calving usually leads to small weak calves rather than abortion

3. Infertility

Leptospirosis has been linked to infertility problems such as reduced pregnancy rates and irregular returns to oestrus. However abortion is the most common fertility problem associated with leptospirosis.


Control of Leptospirosis


Blood testing of affected animals can be a very useful confirmation.

Bulk milk testing can be helpful in dairy herds

Examination of the aborted calf will occasionally confirm infection in the calf, but is more useful for identifying causes of abortion other than leptospirosis

In dairy cattle the risk of spread to humans is increased as there is much greater contact with urine which is the main source of the bacteria. Thus even in herds with no obvious clinical disease prevention is important.



It will significantly reduce the level of abortion, and greatly reduce the spread of disease from cattle to man. Several leptospirosis vaccines are available.

Vaccination is administered via two injections spaced at least 4 weeks apart, the course should be completed in the spring before the main season of transmission of L. hardjo. Yearly boosters are required to maintain effectiveness.

This yearly booster is important as vaccination prevents disease but does not eliminate the organism from the farm, so stopping vaccination often results in the recurrence of the disease.

Please contact the clinic if you require more information or a vaccination protocol tailored specifically for your farm.