How much pine is too much to feed?

Hi, all -- we've just taken down 3 huge old pine trees (I think they're scotch pines if that matters), with 7 more to go... having read and been told that fresh pine boughs fed to goats can be a good vermifuge and that it has antiseptic qualitities as well, we fed a few boughs to the goats, who've eaten it with relish, and started stripping off the green bark. They've mostly all just kidded (one more doe to go, but she's about a month off - managed to keep the buck at bay for that long! :shock: ), if that matters for the pine intake. Can I just keep feeding them the boughs, or is there a point where it's too much? I haven't noticed any scouring at all, BTW, and they've been eating it about 3 days now.

Thanks!

Andrea
NZ