Pteridium aquilinum, Brake Fern, Eagle Fern
A perennial fern which grows up to six feet on a tall, smooth, grooved stalk. The leaves are triangular and have oblong leaflets and smaller sub-leaflets. Brown spores can be found on the underside of the leaves.
A great amount must be consumed for toxicity to occur, however ferns can become addictive to grazers and they will eat it instead of other available forage.
All parts of the plant are toxic.
Appear two-four weeks after continuous grazing. Blindness, weakness, abnormal heart rate, tremors, lack of coordination, loss of appetite, standing with back arched, loss of flesh, jaundice, paralysis.
Contains thiaminase which causes thiamine or B1 deficiency. Can be fatal if not treated, however the animal would have to ingest a large quantity for toxicity to appear.
*It should be noted that we are not veterinarians. This information is written specifically for horses and should be used for reference purposes only. If you think your horse has eaten something toxic call your vet right away.