Peach (Prunus persica
) is a small tree which is grown worldwide for its orchard fruits or an ornamental in gardens.
It produces pink or white blossoms which bloom in the spring, before new leaves appear and fleshy fruit which are edible to humans.
Peach tree parts contain two main cyanogenic glycosides, prunasin in the vegetative organs (leaves, flowers, roots, bark, twigs) and amygdalin exclusively in seeds or pits. Peach trees usually only contain small amounts of these compounds, so unless horses consume an excessive amount of the plant parts, cyanide poisoning is highly unlikely. However, young, rapidly growing leaf tissue and seeds tend to contain increased amounts of cyanogenic glycosides. Toxicity levels increase during periods of frost, drought, application of 2,4-D herbicides, nitrate fertilization, seasonal wilting, or wind damage following storms. As cyanide release requires hydrolysis in the gastrointestinal tract, features of poisoning may be delayed for a few hours. Consumption of 0.25% of the horse's weight (2.5 lb for a 1000-lb horse) of fresh green leaves can be fatal.