What is Blackleg?
Blackleg is a generally fatal bacterial disease of young cattle or sheep of any age. The disease is seen as acute, localised inflammation of muscle tissue due to the growth of the blackleg organism. This is followed by generalised toxaemia or poisoning of the animal causing rapid death.
What causes Blackleg?
Blackleg is caused in most cases by the bacterium, Clostridium chauvoei . Clostridium sept icum or Clostridium novyi are less common causes. The bacterial spores can survive in soil for many years. Spores are ingested from pasture by the animal, they then enter the bloodstream and lodge in the muscle where they can remain dormant without causing ill-effect.
In cattle, unknown ‘triggering’ factors cause the organism to germinate, multiply and cause the onset of blackleg although outbreaks following handling and associated bruising are common. The disease is more commonly seen in young, rapidly growing cattle or cattle on a high plane of nutrition. The organism has been documented to also damage heart muscle and diaphragm resulting in clinical signs not usually associated with this disease.
There is a sudden onset of fever, depression and a loss of appetite. If the affected muscles are in the leg, the animal will become lame. The leg may be swollen, hot and painful in the affected area. Limb muscles are the most common site of infection although muscles anywhere in the body, such as the tongue, can also be involved. A crackling sensation may be noted, when the skin over the affected area is pressed; this is due to gas formation in the tissue.
How do we treat it?
Vaccination is the only effective way to control blackleg and we use Ultravac® 7in1.
Stabler and Howlett would like to thank our partners at Zoetis for their assistance in compiling this post. We recommend and sell the Zoetis range of cattle vaccines.