Cattle Leptospirosis: Reproductive Losses and Animal Welfare

Leptospirosis in cattle causes abortion storms, stillbirths, and acute illness, with significant welfare implications for both individual animals and herd health.

Key Facts

Leptospirosis is caused by Leptospira bacteria transmitted through infected urine, water, and soil
In cattle, it causes two distinct syndromes: acute illness with fever and jaundice (primarily from L. pomona) and reproductive failure
Hardjo biovar is the cattle-adapted strain causing chronic subclinical infection and repeated late-term abortions
Abortion storms can cause loss of 10-30% of pregnancies in naive herds, with significant welfare and economic impact
Infection with Leptospira hardjo causes milk drop syndrome in dairy cows — sudden reduction in yield with abnormal milk consistency
Leptospirosis is a significant zoonosis — farmers, vets, and abattoir workers face infection risk through contact with cattle urine

Welfare Considerations

The welfare impacts of leptospirosis in cattle are often underrecognised. Acute infection causes fever, jaundice, haemolysis, and organ damage — genuinely painful conditions. Chronic hardjo infection causes repeated reproductive failure: cows carry calves to late term before aborting, experiencing physiological and potentially psychological distress associated with perinatal loss. Stillborn and weak calves suffer as well. The zoonotic dimension adds urgency to control — infected cattle silently shed bacteria in urine, putting farm workers at risk of serious illness. Vaccination programmes using multivalent Leptospira vaccines are highly effective at preventing both reproductive losses and human exposure, yet vaccination rates remain suboptimal on many farms.

What You Can Do

Work with your vet to implement a leptospirosis vaccination programme appropriate for your herd and region
Use personal protective equipment when handling cattle urine, placentas, or aborted material
Maintain good biosecurity to prevent introduction of infection from purchased cattle or wildlife
Control access of rodents to feed stores and water sources, as they are significant Leptospira reservoirs
Report abortion clusters to your vet promptly for investigation and to prevent further reproductive losses