Blackleg

• Blackleg is a fatal disease of young cattle that produces an acute local infection, resulting in blood poisoning and rapid death.
• The term "Blackleg" is derived from the site of infection, which is often the leg muscle, and the affected muscle is dark in color.
• Clostridium chauvoei is a Gram +, gas - producing, spore - forming bacteria that can lie dormant in the soil without losing potency.
• Spores of Clostridium chauvoei can be found on contaminated feed or soil.
• In the pathophysiology of Blackleg, spores of Clostridium chauvoei are eaten in contaminated feed or soil, enter the bloodstream and lodge in organs and tissues, including the muscle.
• Spores of Clostridium chauvoei lie dormant, and slight injury to the animal stimulates multiplication.
• Injury to the area reduces blood flow to the area/tissues, thereby reducing oxygen.
• No oxygen = spores of Clostridium chauvoei germinate and multiply.
• As the spores of Clostridium chauvoei grow, they produce toxins and destroy surrounding tissues.
• The toxins produced by the spores of Clostridium chauvoei are absorbed in the bloodstream, making the animal acutely sick.
• Blackleg is often suspected in an animal aged between 6 months and 2 years.
• Blackleg in cattle begins with the animal becoming lame with swelling of a muscle, stopping grazing, and producing gas under the skin that produces a crackling sensation when rubbed with the hand (Crepitus).
• A thrifty calf or yearling is simply found dead with Blackleg.
• When the skin over the infected area is removed, the muscle below is immediately dark, and bubbly bloodstained fluid is seen.
• Diagnosis of Blackleg in cattle can be done through ultrasonographic examination of affected areas like the heart, anaerobic culture of affected tissues, biochemical identification of organisms in tissue samples, and postmortem examination.
• Blackleg is almost entirely preventable by vaccination.
• Treatment/prevention of Blackleg in cattle includes usage of multivalent vaccine (5in1 or 7in1), and some cases may be treated early with antibiotics but would still suffer permanent deformity due to the destruction of muscles.