I talked to a local vet. Good news ultrabac 8 is safe to use for all sheep at any time including pregnancy. We have 4 ewes that are going to lamb in the next couple weeks. My vet said that the lambs will not benefit from the vaccine through the milk as it takes 6 weeks minimum for it to be in their system. He recommends ultrabac 8 for here in the midwest and no need to give a tetanus shot unless they get injured.