Most goats love it and and I've never seen problems with it. I used to pick elderberryleaves in the woods and
feed the goats in the communal animalpatch with it. My greatgrandma taught me that.
Elder contains toxic compounds (I believe it's cyanide-ish stuff), but like some many things, there's a world of difference between the natural occuring toxins and isolated chemical toxins. My guess is that the plant contains it's own balancing ingredients.
I've also eaten many raw elderberries, no probs. That said, I wouldn't worry if my goats snack on my elderberry
trees, but I wouldn't rely on it as a primairy foodsource... to much of a good thing probably.