Lepto in calves - wet weather risk

While we all keep our fingers crossed that the predicted El Nino does indeed lead to a dry winter, the bacteria leptospira (which causes the disease leptospirosis) is hoping the wet weather continues.

Many regions of New Zealand are currently seeing an increase in leptospirosis cases in dogs, sheep, and humans, likely related to the heavy rainfall. Auckland Regional Public Health Service has warned Auckland’s health providers of a possible outbreak of leptospirosis in the public, potentially linked to recent extreme weather events.

Leptospira loves the water and flourishes in wet and warm conditions. Leptospira can survive for a long time in damp soil and stagnant water and spreads gladly after heavy rain or flooding. Bacteria are mostly spread by urine and is extremely infectious. Bacteria could even penetrate skin that has been softened by exposure to water. All these factors may increase the risk of lepto this season.

In cattle, often the most serious disease occurs in calves. In calves, lepto can cause:

• Depression
• High fever and loss of appetite
• Liver disease with jaundice
• Kidney disease with red water (blood in the urine)
• Death
• Many other severe signs

Minimising the number of bacteria shed by animals is a key part of limiting exposure, therefore, reducing infection. This can be done very successfully with vaccination programmes. Vaccinating pregnant cows pre-calving will boost maternal protection, providing calves with up to 12 weeks maternal immunity, provided calves receive enough good quality colostrum in their first 8 hours of life.

Calves are most at risk when:

• Maternal protection runs out.
• Maternal protection wasn’t received due to insufficient or too-late colostrum intake.
• If the mother’s antibody level is low (poor quality colostrum).

Dr Jordan McGimpsey BVSc (Dist.)