The bacterium Clostridium causes a variety of fatal diseases in sheep. In New Zealand they are Black Leg, Malignant Oedema, Pulpy Kidney, Tetanus and Black Disease. A common feature of these diseases is that they are more common in good condition animals, or animals that are growing fast. See each disease under its specific heading.

Clostridial vaccination is very effective in preventing this disease. A vaccine containing components for all of the diseases is the one most commonly used. A programme of a sensitizer dose followed by a booster at least 4 weeks later gives long protection. If pregnant ewes that have previously been sensitized are given a booster vaccination 7 to 21 days before lambing, the lambs will be protected by passive immunity derived from drinking colostrum soon after birth. This protection will last up to 16 weeks.

Only very early intervention with antibiotics will give any chance of saving an animal with a Clostridial disease. The survival rate is very low.