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Leptospirosis; are you putting yourself at risk by not vaccinating your cows?

Sylvaine Lacrosse BVetMed MRCVS, Molecare Veterinary Services

Your vet has most likely mentioned to you at some point the need to ‘vaccinate your cows for Lepto’ and whilst you might feel like your vet is selling you a vaccine, they actually have your herd health in mind!

Leptospirosis is a disease in humans which causes flu-like symptoms such as fever, headaches and muscle pain. Death is rare, but can occur through liver and kidney failure… and therefore, it is not a pleasant experience.

The disease is a zoonosis, i.e. it can be transferred from animals to humans, and is caused by the strain of bacteria Leptospira, of which different types of these bacteria affect different animals. Common carriers include cattle, pigs, dogs and rats. They transmit the disease via urine and contaminate the soil and water. Farmers are particularly at risk, especially those who milk, as they are in regular contact with cattle urine when in the parlour.

Leptospirosis in cattle

The responsible organism in cattle is Leptospira Hardjo, of which two types can cause the disease in the UK; Leptospira borgpetersenii serovar Hardjo and Leptospira interrogans serovar Hardjo).

Clinical signs     

  • Milk drop: occurs 2-7 days post-infection.
  • Abortion: occurs 4-12 weeks post-infection, usually in the last 4 months of pregnancy.
  • Infertility: post-infection, Leptospira localises in the kidneys and the reproductive tract.
  • Weak calf syndrome: the disease is passed transplacentally, and affected calves may die within a few hours of birth.


The carrier state of the disease localises in the kidneys and is therefore mainly spread through urine. It also localises in the reproductive tract so any aborted material is also infected. Peak transmission between cows occurs between June and October when cows are out at grass, as the water source and pasture become infected with urine and/or aborted material.

Contrary to popular belief, rats and other vermin/wildlife do not spread leptospirosis to cattle in this country. This is because they carry different types of Leptospira which unfortunately, we humans can catch! A risk to cattle is that sheep do carry the same type of Leptospira as them, so co-grazing may be a threat.

Control by vaccination

The most practical way of preventing disease in your cattle is through vaccination. It should be noted however, that the vaccine will not protect already infected animals. We encourage farmers to complete the primary course of vaccine 2 weeks pre-turnout as water sources and pasture are a significant source of infection when animals are out at grass.

Primary course: 2 doses 4-6 weeks apart in animals from 1 month of age

Booster: Annually (potentially biannual in high-risk herds)

Leptospirosis causes significant production loss in cattle, mainly through reproductive failure and milk loss, and most likely affecting a lot more cattle than farmers are aware of. Vaccination is a simple way to prevent these losses, and is equally important to protect yourself and your staff from contracting this zoonotic disease.

To find out more phone Molecare Veterinary Services on 01392 872934.