> Can you tell me if black leg is a
> host specific disease? For example
> if sheep and cattle where being
> kept together, are the sheep
> likely to be at risk from this or
> any other disease? I've never heard of a carrier state for any of the blackleg family(claustridiums). Sheep and cattle can get most of the blackleg bugs and therefore should be vaccinated for them. Yearly vaccination of the herd will improve claustrom quality to provide some protection to newborns.
clostridum sp. of bacteria (tetanus, botulism, black leg, big head, etc) are spore forming bacteria meaning they form spores and are very tough against the environment, etc. They are likely everywhere already. Bryan's right, vaccination is the best thing you can do.