Poisonous plants in pastures and hay cause significant welfare harm to horses. Understanding common toxic plants and prevention protects equine welfare.
Poisonous plant ingestion causes welfare harm ranging from chronic liver damage (ragwort - months to develop, irreversible) to acute fatal poisoning (yew - within hours). The insidious welfare problem is that horses often do not avoid toxic plants, particularly ragwort that becomes more palatable when dried in hay. Plant poisoning is largely preventable through regular pasture inspection and prompt removal of identified toxic plants before they are accessible to horses. The welfare responsibility of pasture management includes knowledge of regional toxic plant species and systematic inspection rather than assuming pastures are safe without regular checking.