Blackleg is a fatal disease of young cattle and sheep. It affects the animal in a very severe manner. The bacterium enters the body by ingestion (through food) and then makes small punctures in the mucous membrane of the digestive tract. The microbe which causes the disease affects the muscles and then starts to spread a poison in the body. This is why ultimately the animal is killed.

Common Names

Blackleg is commonly known by the names of black quarter and quarter ill.

Causative Organism

Clostridium chauvoei is the causative organism in most cases. Some affected animals have also been found to be affected with Clostridium feseri. These two microbes are gas-producing bacteria. They also form spores, which can live in soils for many years. The microbes cannot spread Blackleg from one animal to another simply by contact.

Common Symptoms

  1. Cattle not being able to walk properly
  2. Loses interest in food
  3. High temperature
  4. Swelling that develops in shoulder, back, neck
  5. These swellings make a cracking sound under pressure
  6. Gas is formed inside the enlarged swellings

How if Affects Cattle

Once affected with Blackleg, the animal can die within 48 hours. Without proper treatment, cattle can be found dead with no time to react. After the initial symptoms, the bacterium causes a gradual poisoning reaction in the body. In sheep, Blackleg is mostly found after instances of physical wounds. The spores of the bacterium might be present in the gut of the cattle for sometime. These spores do not immediately result in the disease. Medical research is ongoing to find what conditions cause these ingested spores to give rise to the disease.

Regional Impacts

Blackleg can be found in sheep rearing farms and cattle farms. The cattle that are on a high plane of nutrition and in the 6 to 24 months age group are most susceptible to the disease.

Risks & Dangers

Blackleg is caused by a spore-forming bacterium. The spores can survive in soil for many years. After they are ingested from pasture by the animal, they then enter the bloodstream. In this way they can remain in the muscles without causing any problem. This is the danger of Blackleg. Seemingly healthy cattle and sheep can also be infected without showing any outward signs. Blackleg kills affected animal very fast. So, it is futile to treat one animal at a time.


In the early stages of Blackleg, treatment with penicillin or other antibiotics in large doses is helpful. The cattle which recover from this disease may have a weak muscle in legs, shoulder, etc.

Vaccines & Prevention

Blackleg can be prevented by vaccination. The most commonly used clostridial vaccination in cattle is a 7-type prevention vaccine. It gives your cattle full protection from 7 microbes including the one responsible for Blackleg. The best way of preventing more instances of Blackleg will be by revaccinating animals. Burning the upper layer of soil to eliminate spores with oil or straw also works well.
Covexin® 8, 10 doses, 50 ml
Covexin 8
Ultra Choice 8
Ultra Choice 8
Fortress 7
Fortress 7

References and Resources

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P.O. Box 913
Spring Branch, TX 78070