I've always given two shot's to the kids, first cdt is 5cc sub q and 4 weeks later is 2cc sub q, I also vaccinate for pnemounia, 2 cc per goat per year, I give the momma does a cdt 2cc and a bose shot 4 weeks out from kidding, I've done this every year and we drink the raw milk. Never thought to much about it coming thru the milk, we wait to drink the milk two weeks out from kidding. interesting.
It's a selenium shot. Some people need it but many are overusing it and using when they should not be. It must be given to you by a vet because it is VERY dangerous and can kill. People are using it too much and overdosing and vets are starting to crack down. Vets are not liking to give it out now either.
We vaccinate our does about six weeks before kidding (if we know the exact breeding date), then the kids at eight weeks and twelve weeks of age with CDT. I know some breeders don't vaccinate, and that's fine, but we lost a doeling to tetanus a decade ago and don't ever want to see a goat go through that again. And we do drink raw milk from our does and have never thought the vaccinations were a problem.