goats & sheep

we've had goats for just a few years and their "pasture" was lawn before so there's really not any browse... we do provide occasional browse, hay, etc... My question is about trying to improve the pasture. It's becoming full of buttercups and I've read that spreading lime can help change the...

so does any one use the preventative vaccine prior to breeding sheep and goats? Like the vibriosis or enzootic shot-vaccines? When do you give the shot? If so, where do you get them/buy them? What are they called? Are they worth the money, or necessary?