In the Crookwell district, leptospirosis is increasingly impacting on reproduction and fertility in cattle. A contagious bacterial disease, the organism is found in infected urine and tissues in a wide range of animal species - cattle, pigs (including feral pigs), sheep, goats, horses, rodents, wildlife and dogs.
Most producers in the Crookwell district are now routinely vaccinating against leptospirosis in cattle, to protect both their cattle and the health of their families and employees who may come in contact with the disease.
Danger to humans
While this article focuses on leptospirosis in cattle, it’s important to recognise this is a zoonotic disease – that means it is capable of moving from animals to people. All strains of leptospirosis affecting cattle can cause severe illness in humans. For further information about leptospirosis in humans, see the public health fact sheet on leptospirosis at NSW Health.
The disease in cattle
Leptospirosis locates in the kidneys of affected animals and the reproductive tract of females. While affected animals often don’t show symptoms, these healthy carriers shed the bacteria in urine or at birth, contaminating the environment. They can be the primary source of infection for other cattle (and humans).
Outbreaks are more common in wet seasons as the organism survives best and for long periods in moist, dark places including damp soil, fresh water and vegetation (it is killed by sunlight and dry conditions).
Outbreaks
The introduction of infected animals into a disease-free, unvaccinated herd can cause severe outbreaks. Symptoms include:
- high precentage of abortions in cattle more than 5 months pregnant
- drop in milk production and mastitis, particularly in dairy herds
- high death rate in calves with symptoms including the classic “red water” (dark red-brown urine), fever and jaundice.
Diagnosis
We can assist with diagnosing leptospirosis in your herd. This requires:
- blood tests from 10-15 animals in the herd
- examination of fresh aborted calves and afterbirth
Control
Animals in outbreak situations develop only a temporary immunity – and only to that particular strain of leptospirosis. Unless the entire herd is vaccinated, immunity starts to wane and the herd becomes susceptible to further disease.
CVH always has leptospirosis vaccine in stock – talk to us about a vaccination program to suit your herd and situation.
Following is a recommended vaccination program:
- In previously non-vaccinated herds, give every animal two doses of leptospirosis vaccine 4–6 weeks apart. Follow this with annual boosters.
- Cattle previously vaccinated should receive annual boosters.
- Vaccinate all breeding cattle during early pregnancy. This provides the most effective protection during pregnancy and a high level of protection to calves.
- Give all calves 2 vaccinations 4-6 weeks apart. They can be vaccinated from 1 month of age, but if born to vaccinated cows, vaccinate at 3 months of age to prevent interference from maternal antibodies.
- Vaccinate all unvaccinated introductions to the herd immediately with 2 vaccinations 4-6 weeks apart. Maintain annual boosters.
It’s important to maintain vaccination programs across your herd. While the vaccination can protect against clinical disease, it does not fully eliminate the shedding of bacteria in carrier animals.