Leptospirosis and Cattle Health

Leptospirosis is a bacterial disease that can cause abortions, weak calves, and poor fertility in cattle. It can also make people sick, so handling matters.

Key points

Leptospirosis spreads through urine and contaminated water.
Abortion, weak calves, and poor fertility are common signs.
People can be infected, so wear gloves and wash up.
Vaccination and water management are part of prevention.
Call your vet after an abortion and use lab testing to find the cause.

What leptospirosis is

Leptospirosis is caused by bacteria that live in the kidneys of infected animals and spread through urine. Cattle, wildlife, and other animals can carry it. Some strains are adapted to cattle and others come from wildlife and other livestock.

Infection can be quiet in some cows. In others it causes abortion, stillbirths, weak calves, or lower milk and fertility.

The strain matters. A vaccine or test that targets the wrong strain may not help, so ask your vet which strains are common in your area and in your herd.

How it spreads

Bacteria move through contact with infected urine, contaminated water and mud, and fluids from aborted fetuses and afterbirth. Standing water, wet pastures, and ponds shared with wildlife are higher-risk spots.

Stocking density, flooding, and shared pastures can all raise exposure. Purchased cattle can bring in new strains.

Infected cattle can shed bacteria in their urine for some time, even without looking sick. That is why herd-level thinking matters more than watching for one sick animal.

Contact with urine from infected animals
Contaminated ponds and standing water
Wildlife sharing water and pasture
Aborted fetuses and fluids
Purchased or shared cattle

What it looks like in the herd

Often the first sign is abortion, sometimes late in pregnancy, or calves born weak or dead. A herd may also show poor conception rates. Some cattle, especially calves, can show fever, dullness, and in severe cases dark urine and anemia.

These signs match many other diseases, which is why lab testing through your vet matters. Do not assume the cause from signs alone.

Take note of abortion timing and the number of cows involved. Late-term abortions in several cows are a pattern your vet will want to hear about.

Human health

Leptospirosis can infect people who come in contact with infected urine or birth fluids. Wear gloves when handling aborted fetuses, afterbirth, or sick animals, wash well afterward, and keep children away. Follow guidance from your doctor, your vet, and CDC about protecting yourself.

If you have flu-like illness after working with cattle, tell your doctor that you work with livestock.

Pregnant women, people with weakened immune systems, and children are especially wise to avoid contact with birth fluids and contaminated water.

Prevention and control

Talk with your vet about vaccination and about which strains matter in your area. Vaccines differ in what they cover, and timing matters, so follow your vet's advice and the label. Good practices also include limiting wildlife and livestock access to water sources, fencing off stagnant water, and controlling rodents.

Quarantine and ask about testing for new cattle, and keep aborting cows separate until your vet gives the all-clear.

Ask your vet how vaccination fits with your breeding plan, since timing before breeding is often part of the discussion.

After an abortion

Call your vet when a cow aborts, and keep the fetus and afterbirth for testing if your vet asks, handling them with gloves and keeping them from dogs and other animals. Do not touch or dispose of materials without guidance.

Record the cow, date, stage of pregnancy, and what you saw. Several abortions in a short time call for a prompt call to your vet, since some causes are reportable or carry broader risk.

Common mistakes

Handling aborted material without gloves, leaving aborting cows with the herd, assuming one abortion means nothing, and skipping vet testing are the usual errors. Another is relying on vaccination alone and ignoring water and wildlife. Combine the steps, and ask your vet for a plan that fits your ranch. Follow label directions and withdrawal times on any product or treatment.

Do not forget the water. Fencing off a pond or fixing a drainage problem may do more for long-term control than any one product.

When to get help: Call your veterinarian after any abortion or cluster of weak calves, and talk about vaccination and testing. If you feel ill after handling cattle or birth material, tell your doctor about your livestock work.

Sources and further reading

Organization homepages are linked so you can search them for current guidance on this topic.

More in Herd Health & Cattle Care

← Babesiosis in Cattle: What Ranchers Should Know Brucellosis Testing and Regulations →