Hampton Veterinary Centre Hampton Veterinary Centre Hampton Veterinary Centre


Leptospirosis infection is most common during spring and can infect cows, sheep and goats causing infertility, abortion and poor milk yield. The disease can also be contracted by humans (zoonotic infection), causing flu-like symptoms and in extreme cases resulting in hospitalization.

Infection occurs from contact with infected urine or products of abortion. The bacteria can pass through mucous membranes and then localize in the reproductive tract and kidneys. They are then shed from the kidneys, which can persist for months or years. Leptospira can then survive in water or in mud for extended periods of time.

In a naïve cow the first clinical sign is “flabby bag”. The milk yield can suddenly drop by up to 75% in all 4 quarters, leaving the udder soft and “flabby”. The milk looks like colostrum and can contain blood clots. This presentation may be mild and pass unnoticed or the cow may also become lethargic and run a fever.


A lot of herds are endemically infected with Lepto so the acute stage is rarely seen. In these herds effects are more likely to be seen in fertility: Abortion is the most common clinical presentation. This can occur from 4-12 weeks after infection and tends to happen in the last 3 months of pregnancy. Cows infected late on in pregnancy may give birth to small, weak calves. There is also evidence of infertility and early embryonic death. This will show up as increased level of repeat breeders and PD negatives.

There are three important risk factors when considering Lepto infection:

1. Access to common watercourses as the bacterial can survive in water.

2. Grazing with sheep as they can act as carriers.

3. Buying in cattle – including shared or hired bulls.

The best way to monitor your Lepto infection status, especially if you are unvaccinated, is by submitting a bulk milk sample for testing. To prevent infection in your herd and zoonotic infection, we encourage vaccinating: This prevents cows from contracting leptospirosis and reduces shedding of the bacteria, thus reducing the chance of spreading the infection. Vaccinating is best done before turnout so start thinking about it now!