| Call a vet when high stock losses occur to protect market access |
|---|
Always ask your veterinarian to investigate whenever sudden death and high death rates or unusual behaviour occur in livestock. In the acute form, pulpy kidney has similar signs to anthrax, which is a reportable disease with human health risks and potential to impact some export markets if not contained rapidly. If you see unusual disease signs, abnormal behaviour or unexpected deaths in stock, call:
|
What is pulpy kidney?
Pulpy kidney (enterotoxaemia) is a disease of sheep, goats and cattle. It occurs in sheep when a bacterium that normally inhabits the animal’s intestines without causing problems begins to multiply and produce a toxin that poisons the animal.
The bacterium, Clostridium perfringens type D, can build up when there is a sudden change to a low-fibre, high-carbohydrate diet. This can occur when sheep are moved onto lush, rapidly growing pasture or cereal crops, or when sheep are fed grain.
Which animals are most at risk?
Pulpy kidney most commonly occurs in rapidly growing unweaned or weaned lambs, on lush pasture or grain.
In older sheep, pulpy kidney is most likely to occur just after they are moved to good feed from poorer feed. However, the disease can occur at any time. Stinkwort (Dittrichia graveolens), a pungent-smelling annual weed, may predispose sheep to the disease, due to its barbed hairs damaging the intestines and enabling increased toxin absorption.
Diagnosis
The following combination of conditions are likely to lead to a diagnosis of acute pulpy kidney:
- unvaccinated or incorrectly vaccinated sheep
- good feed (pasture or grain)
- sudden deaths in well-conditioned sheep and
- typical post-mortem signs (see below).
A veterinarian can assist with diagnosing pulpy kidney and provide advice on control and vaccination.
Clostridium perfringens type D can also cause a chronic form of the disease known as focal symmetrical encephalomalacia (FSE). This disease causes neurological signs and requires laboratory diagnosis. It can occur in vaccinated flocks and is normally associated with a high-energy diet.
Signs of pulpy kidney:
Lambs
- good condition
- found dead, often on their side with limbs extended and head thrown back
- die quickly with convulsions.
Adult sheep
- good condition
- often found dead
- may stagger
- may scour.
Post-mortem signs (in recently dead sheep)
- haemorrhages under the skin and on the heart and kidney
- straw-coloured or blood-tinged fluid, sometimes with soft, jelly-like clots in the sac around the heart
- small intestines tear easily and their contents are sparse and creamy
- carcass decomposes within a few hours of death
- the kidneys usually decompose more rapidly than the other organs and become dark and jelly-like, hence the common name ‘pulpy kidney’. However, sheep can die from this disease without the kidneys becoming pulpy.
Signs of focal symmetrical encephalomalacia (FSE)
- aimless wandering, blindness, lack of coordination
- may scour
- die after a few days.
In FSE, the only changes are in the brain, which usually can only be seen under a microscope.
Treatment
There is no antidote or specific treatment for sheep affected by pulpy kidney. A veterinarian may prescribe treatment for valuable animals but the prognosis for affected animals is poor.
Ideally, when the disease is first diagnosed, vaccinate the affected group immediately then turn them on to poorer feed or hay for at least two weeks, until immunity develops. If pulpy kidney occurs in a previously vaccinated flock, give an immediate booster dose to restore immunity and prevent further losses.
A change in diet alone will usually stop an outbreak, but without vaccination the disease could reappear later. If the sheep are not vaccinated and their diet is not changed, an outbreak of pulpy kidney may continue for some time. Mortality rates may be as high as 10% of the group and it is usually the best sheep that die.
Prevention
Pulpy kidney can be prevented by maintaining a sheep vaccination program.
The vaccine is available in various combinations:
- with tetanus and cheesy gland (CLA) vaccine (3-in-1 vaccine)
- with other clostridial vaccines, such as that for tetanus, blackleg, black disease and malignant oedema (6-in-1 vaccine)
- with selenium and vitamin B12 (or both)
- with moxidectin (in an injectable form) to treat worms.
Sheep not previously vaccinated must have at least two injections, four to six weeks apart, to achieve long-term high-level immunity.
To maintain a high level of immunity, booster doses are needed at yearly intervals. Generally, the two initial injections, followed by annual booster injections over the next two years, will protect sheep for life.
If the booster injection is given to ewes in late pregnancy, the lambs will receive temporary immunity via the colostrum, which will protect them for about six weeks. Lambing ewes need a booster dose every year.
| Sheep class | Pulpy kidney vaccination |
| Lambs | Two doses of vaccine 4-6 weeks apart |
| Ewes | Annual booster 2-6 weeks before lambing |
| Other adult sheep | Annual booster vaccination (provided they had initial vaccination course) |
| Introduced sheep | Adult sheep not previously vaccinated, or with an unknown vaccination history, need two doses 4-6 weeks apart. |
Booster doses may also be necessary in special instances, such as when putting sheep onto storm-damaged grain crops or into a feedlot.
If producers choose not to vaccinate, it may be possible to prevent pulpy kidney by avoiding sudden changes to better feed.
Welfare
Pulpy kidney is a preventable disease which can cause high mortalities.
Producers must consider their obligation to reduce the risk of suffering in their flock when deciding on a vaccination program suitable for their farming conditions.
Diseases that look like pulpy kidney or FSE:
Pulpy kidney:
- anthrax (a reportable disease)
- poisonous plant e.g. gastrolobium (1080) ingestion.
FSE:
- polioencephalomalacia (vitamin B1 deficiency)
- lead ingestion (report suspicions of lead poisoning or ingestion to a vet)
- circling disease (listeriosis)
- grain engorgement.
Call a veterinarian when high stock losses occur
Always ask your veterinarian to investigate whenever sudden death and high death rates or unusual behaviour occur in livestock. In the acute form, pulpy kidney has similar signs to anthrax, which is a reportable disease with human health risks and potential to impact some export markets if not contained rapidly.
If you see unusual disease signs, abnormal behaviour or unexpected deaths in your stock, call your private veterinarian, a veterinary officer at the Department of Agriculture and Food, or the Emergency Animal Disease hotline on 1800 675 888.
DPIRD veterinary officer contacts
DPIRD field veterinary officers can provide more information about pulpy kidney in sheep. To find the contact details of your closest DPIRD Field Veterinary Officer, go to the Livestock Biosecurity program contacts page.