North Coast Local Land Services District Veterinarians have diagnosed outbreaks of the deadly Clostridial disease, Blackleg, on several properties on the North Coast in recent weeks.
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Blackleg is a commonly seen acute disease of cattle and sheep with a high rate of mortality. The disease is caused by a spore forming bacterium which is a normal inhabitant of the intestinal tract, but is usually present in low numbers. The spores of the bacterium, Clostridium chauvoei, are also found in the soil and can remain viable for years, often causing outbreaks where soil has been disturbed manually or by rain or flood events..
North Coast Local Land Services District Veterinarian, Dr Cassie Maria said, “Commonly the animals that are most affected are in excellent health, and gaining weight. Outbreaks occur where a few new cases are found each day, sometimes for several days. Most cases are seen in cattle from 6–24 months old, but occasionally thrifty calves as young as 6 weeks and cattle as old as 10–12 years may be affected.
Typically, the onset of the disease is sudden, with deaths being seen without any warning signs. However, you may see signs prior to death including lethargy/depression and lameness. Characteristic lesions causing lameness are oedematous or crepitant swellings (giving the feel of ‘bubble wrap’) in the muscle of the hip, shoulder, check, back or legs, although sometimes lesions are internal and therefore not externally visible. If death is not sudden, it will generally occur within 12-48 hours.
Post-mortem, the carcass will become bloated very quickly and may sometimes be confused with bloat. There may also be bloody froth coming from the nose. The carcases are highly contaminated with the spore-forming bacterium and should not be opened due to the release of spores leading to the contamination of the soil and ultimately causing the further infection of other cattle. The carcass should ideally be burned or deeply buried.
Cassie said, “The disease is highly preventable with the use of an easily available vaccine that is administered under the skin.
“The use of 5-1 or 7-1 vaccines will provide protection against Blackleg as well as other clostridial diseases including pulpy kidney and tetanus.
“The vaccine should be administered to calves from 3 months with a second injection given 4-6 weeks later. A booster is highly recommended.”
For more information please contact your private veterinarian or the North Coast Local Land Services District Veterinarian team.