[twizzel]

I don't think immunity occurs until a week or so after the 2nd jab of heptavac. That said I've not lost one so far after it's had the first jab. So if you have a group of 3-4 week old lambs it would be expensive but worth doing them now, then when they have their 2nd jab in 4-6wks I would do you other lambs first jab. So you would need 3 bottles instead of 2, but that would hopefully start to halt pasturella. That said it would be worth if you have any more deaths getting the vet to pm a fresh carcass and see exactly what is going on. Pasturella sounds likely but you'll never know for sure unless you pm one.

[shep53]

I don't think immunity occurs until a week or so after the 2nd jab of heptavac.

   Immunity starts after the first injection but at low levels then  2wks after the second injection it is at maximum level