Know the VERY poisonous plants in your area and patrol for them regularly. I don't know Florida plants at all, but around here, anything with "laurel" in it's name is pulled out carefully, trying to get all the roots, and safely removed. Also yew and a few other garden plants that tend to wander into the pasture. I suspect I lost one goat a few years ago that ate some fast-growing spring laurel that was quite lush after some land clearing attempts. And this summer, I had a crisis with a doeling that seemed to be plant poisoning....a neighbor had done some trimming along the fence and some trimmings were reachable....also, the goats got into a pasture that I hadn't patrolled recently, and there was laurel creeping into it in one corner. One of my six threw up all night, a baby I was in the process of weaning (un-weaned her fast!)
On the other hand, my goats have access to many plants that are mildy toxic and appear on some lists (cherry, walnut, oak, poke, etc) but have proven to be no problem at all, since they have plenty of choices in a big pasture. I feed hay when the pasture is low to reduce temptation. But there are some super-toxic plants that they WILL eat, so be alert.