Black Disease

Infectious necrotic hepatitis, or “black disease,” usually affects cattle on a high grain ration and is caused by Clostridium novyi type B. Black disease is somewhat similar to red water disease. The same pattern of events occurs: Clostridium novyi type B is ingested; the bacteria lodge in the liver; damage to the liver occurs; and the bacteria replicate and release toxins. The differences are that the toxin released is somewhat different, and flukes may not play as important a role in this disease in cattle as they do in sheep. However, fluke infections can create a desirable environment for this disease to occur. The toxin released causes severe tissue damage to the liver instead of causing red blood cell destruction (as in red water).
On postmortem examination, the liver will have large areas of damaged tissue that are gray to blackin color. The dark color is what gives rise to the name “black disease.” The diseased areas will also be associated with a foul smell. Infected animals die quickly without many signs of illness, usually before treatment can be considered. Prevention depends on vaccination.