while it is trial and error, if you could get a soil test done, you're way ahead of the game, knowing exactly what you need.

It is very hard to overdose with copper.  With the boluses they said they gave goats 4 times the dose with no ill effects. Goats get rid of copper to quick for it to get to toxic levels Most of the time.
 They also need it to fight off parasites also.

  Man, that is the problem! Dang goats get rid of EVERYTHING so quick, that is
why we have to do so much extra work!  (I do love my goats, though.)

There are 2 types of "yellow" salt/mineral blocks. The original yellow ones are regular mineral blocks with extra sulfur added.

Then there are the yellow ones with Rabon added for pest control.

However, if they are pregnant, excess copper can kill the kids. Come to find out that's what killed my unborn, almost term kids this spring and almost made me lose my Chrysta, their mother. I had changed to a mineral with higher copper, because they were showing signs of copper defeciency. I was changing over slowly, mixing with the old type. Chrysta got out of her stall (long story involving trepassers) and into my back porch and ate a hugh amount of the minerals. When they did the tests on the dead kids, they found toxic levels of copper in their system.

The copasure is released at a slower time frame, so they don't OD on it. I am getting ready to order mine to dose all my goats with.

From Jeffers? Can you give copasure to pregos?

I do. Its a slow release and it takes Alot to OD them on Copper One study I read said they gave 4 times the dose and there were No side affects.

Here are some links I have on using Copper Oxide.

http://attra.ncat.org/attra-pub/PDF/parasitesheep.pdf

http://www.saanendoah.com/copper1.html
http://www.goatspots.com/copper.html