Clostridia are group of anaerobic, spore-forming organisms found in the soil/environment, which produce rapidly fatal disease by secretion of potent toxins. Conditions such as botulism, blackleg, bacillary haemoglobinuria, malignant oedema and tetanus are all caused by clostridia.


Botulism is a lethal food poisoning in cattle caused by eating material that contains Clostridium botulinum toxins. The incubation period before clinical signs appear varies from a few hours to two weeks, making it difficult to identify the causative material eaten by affected animals. The most common manifestation of the disease in cattle is a subacute disease with restlessness, incoordination and difficulty to swallow developing into recumbency, paralysis and death within 1-7 days.

The bacteria and the disease occurrence are world-wide. In the UK, cases are likely to occur either due to ingestion of contaminated silage or contact with animal carcasses or skeletons of dead animals containing the toxin. The use of poultry litter as fertiliser on cattle pastures has been identified as a risk factor, due to the poultry mixed with the litter.

Bacillary haemoglobulinuria

Bacillary haemoglobulinuria is a rapidly fatal disease caused by C. oedematiens type D. The disease is associated with liver damage primarily caused by liver fluke. The condition is fairly rare in the UK. Young stock or dry cows inspected less regularly are often found dead. In lactating cows, a sudded drop in milk yield associated with high fever is seen. Other clinical signs include ruminal stasis with or without apparent abdominal pain, rapid breathing, dark red urine, jaundice and death within a short time of the onset of clinical signs.

Spores of C. oedematiens type D can be found both in the soil and in the livers of normal cattle on farms where the disease occurs.


Blackleg infection is caused by Clostridium chauvoei and is almost allways associated with wound infection in cattle. Most cases occur in young stock between 10 months and two years of age. Feet or legs and the tongue are often the predilection site. Within 48 hours there is a high fever and if limb muscles are involved the animal becomes stiff and unwilling to move. Skin discolouration, subcutaneous oedema and gas production may be present and perineal oedema is sometimes seen. Infections of the head may produce marked oedema and even bleeding from the nose. Death usually follows a period of anorexia, profound depression and prostration.

The spores of C. chauvoei survive well in the soil.

Malignant oedema

Malignant oedema is caused by the infection of wounds with bacilli of the genus Clostridium (C. oedematiens type A; C. chauvoei; C. perfringens; C. sordellii; C. septicum). The condition is fairly rare and sporadic, but outbreaks involving several animals may occur after an event that has caused bruising or wounds (e.g. penning for a short period). Clinical signs appear rapidly after infection and at the site of infection a swelling will develop which will ‘pit’ on pressure. Gas may be detected, as the skin becomes darkened and tenser. A high fever is present and toxaemia develops. The animal dies within 1 – 2 days.


Tetanus is caused by the toxin tetanospasmin released from the spore-forming bacillus Clostridium tetani. The disease in cattle occurs most often after surgical intervention or difficult calving after spores gain entry to a wound. Germination of spores occurs only if the microenvironment is anaerobic. After germination of the spores within the wound the C. tetani bacilli proliferate and produce toxin.

The incubation period can be very variable from 3 days to several months but most cases occur usually after about 10 days. At first the animal appears slightly stiff, becomes unwilling to move and develops a fine muscle tremor. The temperature rise is variable (39 – 42°C). The general stiffness of the limbs, head, neck and tail increases after 12 – 24 hours. The animal shows hyperaestesia and repeated spasms. Mastication becomes difficult due to tetany of the masseter muscle (lockjaw), food is chewed with difficulty, the animal drools saliva and bloat often occurs. There is retention of the urine and constipation. The animal becomes recumbent, with the legs rigidly extended, opistotonos and the jaws become rigid. The animal usually dies due to respiratory failure 3 – 4 days after the onset of clinical signs. Milder cases, which develop more slowly, can recover over a period of weeks or even months.


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