I understood heptavac p was protection against clostridial diseases, most notably pasteurella pneumonia ( a usually fatal condition). we've always vaccinated and never had it- could we do without it - don't know but not willing to risk it. All our flock had orf last year seemingly bought on by grazing in a rented paddock which had lots of rough ground which caused scratches on the skin allowing the virus to infect the affected areas. joint ill in basic terms is infection in thr joints which most commonly gets in through the naval of newborn lambs soon after birth. now i'll find out how much I really know as I don't believe hep p has anything to do with orf or joint ill