Neonatal Clostridial Diseases in Lambs
Clostridial diseases pose a significant threat to lamb health and survival during the early weeks of life. Among the most common clostridial conditions diagnosed in lambs by SRUC are lamb dysentery and pulpy kidney disease. Effective control of these diseases relies heavily on prevention, with maternal vaccination playing a central role.
On most farms, ewes will receive a clostridial vaccination around four weeks prior to lambing. The timing boosts production of antibodies in the colostrum which helps to protect young lambs from clostridial disease and also helps protect the ewes. This colostral protection relies on good ewe nutrition and genetics allowing for the production of good quality and quantity of colostrum, which then needs to be ingested and absorbed by the newborn lamb.
Lamb Dysentery
Lamb dysentery is caused by the bacteria clostridium perfringens type B, which produces several toxins, one of which attacks the intestine of young lambs. Colostrum, even from unvaccinated ewes, helps to prevent the activation of this toxin. Disease is most common in lambs in the first week of life but can be seen in lambs up to three weeks old. There is increased risk of this disease in any lamb with poor colostrum intake and older lambs born to unvaccinated dams.
Disease is more common in outdoor lambing flocks with an associated peak in diagnoses in April. The most common presentation is sudden death, although a bloody scour can be seen prior to death. Lamb dysentery is not the only cause of bloody scour and a postmortem examination is needed to confirm the diagnosis. There is often a characteristic gas bubble formation, thickening and bleeding in a section of the small intestine wall (pictured below). These changes become harder to detect if the postmortem is delayed for more than 24-28 hours after death. Your vet can take samples from the intestine and test for the presence of clostridial toxins and/or arrange microscopic examination of the intestine to confirm a diagnosis of lamb dysentery (samples should be as fresh as possible).
Pulpy Kidney
Pulpy kidney (clostridium perfringens type D disease) is the most common clostridial disease seen in the UK sheep flock. The majority of cases are seen in April and May. Disease can be seen in the first few days of life; however, most diagnoses are made in older lambs where colostral protection has waned and the primary course of two clostridial vaccinations have not yet been completed.
In very young lamb’s pulpy kidney disease affects the brain, and in the hours before death, lambs can be seen falling, unable to get up, having seizures or with rigid muscles. Older lambs are most often found dead with no prior signs of ill health.
Postmortem examination is again the only was to make a diagnosis of pulpy kidney. Classic findings include an excess of fluid around the heart, with a so-called “chicken fat clot” present, fluid in the lungs, soft, ‘pulpy’ kidneys and swelling of the brain causing it to flatten against the skull. These changes can be subtle, so diagnosis needs to be confirmed by detection of toxin in the intestinal content and classical changes in the brain when examined under the microscope.
If you have concerns over clostridial disease, and if you have not already done so seek advice from your vet to discuss and plan vaccination in order to protect your flock.
Fiona Crowden, SRUC Veterinary Investigation Officer, fiona.crowden@sac.co.uk
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Posted by Unearthed News on 15/04/2025
