Clostridial diseases in Cattle are caused by bacteria of the genus Clostridium. Clostridia are widespread in the environment and are normally found in soil and feces. They form highly resistant spores that can survive in the environment for very long periods. They are also present in the gastrointestinal tract and as spores in tissues of healthy animals. Disease occurs when these bacteria enter the body (via cuts, abrasions or ingestion) and conditions in the body allow multiplication of the bacteria and/or toxin production. TETANUS: Tetanus usually results from contamination of deep puncture wounds. Castration and dehorning wounds are another risk, as are wounds from calving trauma. Clostridium tetani organisms remain at the site of entry, multiply, and produce a toxin that affects the nervous system, causing stimulation and contraction of the skeletal muscles. Respiratory failure ends in death. MALIGNANT OEDEMA: Caused by Clostridium septicum, along with C. chauvoei, C. perfringens,C. sordellii and C. novyi, produce malignant oedema. Malignant oedema results from wound contamination by soil, allowing entry of the clostridia. Deep puncture wounds, castration wounds and calving injuries are high risk. Infection can also occur via the umbilicus (navel) in newborn calves and following injections if proper aseptic technique is not used. Toxins are produced at the entry site. This causes extensive swelling, with accumulation of bloody or clear fluid, and tissue death followed by gangrene. Toxins are absorbed into the bloodstream, causing fever, weakness, trembling, and then death. BLACKLEG: Black leg tends to be a disease of young cattle from 6 months to 2 years old. It occurs more often in rapidly growing animals on a high plane of nutrition. Spores of Clostridium chauvoei lie dormant in the muscles of healthy animals. ENTEROTOXAEMIA (PULPY KIDNEY): The organism that causes enterotoxaemia is a normal inhabitant of the intestine but is usually present in low numbers. These organisms produce little toxin and, under normal conditions, are removed by normal gut movements or are inactivated by circulating antibodies. Sudden changes in diet, grazing lush, rapidly growing pastures or young cereal crops; or heavy grain feeding (as in feedlots) enables the bacteria to multiply rapidly. Toxemia occurs when the movement of food in the intestine slows or the organisms multiply and produce toxin faster than it can be removed or neutralized. Enterotoxaemia is caused by proliferation of Clostridium perfringens type D, with toxin production, in the intestine. A number of toxins are produced, but the most important toxin damages blood vessels and the nervous system. The disease tends to occur in young, rapidly growing animals in good condition and on a high plane of nutrition. Signs of disease include diarrhea, bellowing, mania or dullness, blindness, convulsions and death. Animals may just be found dead. BLACK DISEASE: Black disease is thought to occur when there is damage to the liver - such as occurs with migrating liver fluke - that allows Clostridium novyi to multiply and produce toxin. The toxin causes severe liver damage and death. BOTULISM: Caused by Clostridium botulinum is present in decomposing animal and plant material. Toxins are produced by Clostridium botulinum in the decaying material. Animals get botulism by ingesting the toxin. The most common source of toxin for cattle is feed contaminated by carcasses such as those of mice or birds, or chewing on bones. Botulinum toxin causes a flaccid (floppy) paralysis. The animal cannot chew or swallow and will drool saliva. Paralysis of the respiratory muscles results in death.
Posted on: Thu, 21 Aug 2014 13:42:05 +0000
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