As the others mentioned, any soap recipe can be used. You can just substitute goat's milk in place of the water.
For an ivory soap using goat's milk, I freeze my goat's milk. Then I add the lye to the frozen goat's milk, stirring well. It will be slushy until it tries to warm up. I do this in a bowl that is in a larger bowl of ice water. If you keep this solution cool, the goat's milk won't turn brown (or worse, orange!).
Using white oils also helps keep the color white- I use tallow and olive oil primarily but castor oil (up to 8%) helps with lather/bubbles.
One very very nice goat's milk recipe (I've posted this in the forum before, with other goat's milk recipes):
10% shea butter
20% coconut oil
12% tallow
50% olive oil, pomace
8% castor oil
Frozen goat's milk for water
Superfat 8%
Don't gel.
This is an ivory soap, that is rich and wonderful.