Treatment for bracken fern poisoning is relatively straightforward once it has been diagnosed. Your veterinarian will put your horse on a regimen of thiamine supplementation over the course of several days until your horse shows signs of improvement.
One of the things in your favor is that horses generally do not choose to eat bracken fronds; they will only eat them when they have no other choice. In rare cases the horse may develop a taste for the plant (this affliction is similar to acorn poisoning).
While it is all but impossible to completely eradicate this plant from your horse's environment, knowing how to recognize the leaves, keeping the growth to a minimum, and making sure that your horse has no reason to resort to eating them will go a long way toward avoiding a potentially deadly poisoning.
The act of feeding animals with a range or pasture
A substance that causes chemical change to another