jaykay, I've emailed you the product label for Grazon-90. Sorry I can't remember where I downloaded it from now, or I'd post the link.
I know nothing whatever about its effect on goats specifically but have always understood that livestock can go back on after 2 weeks. The issue I rant on about is its persistence, in that the active chemicals will still kill non-monocots after hay or silage is made, eaten and passed through the digestive system of a herbivore. Not a problem if all your FYM ends up only on pasture - the persistence is then very useful!, continuing to kill dockins, nettles, etc - but very much a problem if you or anyone else uses your FYM on the veg patch or a non-grass crop, or if your hay ends up fed to horses whose dung is used on the roses or veg.
It's also evil to all aquatic life, so the label gives guidance about its use near watercourses or where the land drains through to watercourses.