Perennial pea (Lathyrus latifolius) is a perennial climber that can be toxic to horses. Perennial pea plants produce large showy, pea-like pink clusters of elongated flowers and flattened pod fruits. Lathyrus spp. are generally very similar to hairy vetch (Vicia spp.).
Toxic components
All parts of perennial pea contain the enzyme beta-aminoproprionitrile (BAPN), which can cause lathyrism. Lathyrism is a paralysis syndrome. Signs develop from consumption of large quantities of perennial pea over a long period of time. Once signs develop however, they are irreversible, other than surgery might correct roaring.
