Caprivite is well tested and established - but it may take goats a while to get used to it. I also use some seaweed powder during their pregnancies (mixed into sugar beet shreds), as well as garlic granules. I don't use any other supplement. (but they have daily doses of branches, grass (in the summer I do not feed any hay, just grass, freshly cut).
I would be a bit careful as you can easily overdose on some things.
Also I would speak to my vet re any known mineral deficiences in your local soil, and if there is a possibility do a soil test/grass test - in the summer. Then you may need to add specifics in other forms, such as drench or injection.