An introduced plant from the far East, but has now escaped to become a weed in some areas.
Mostly in the South Eastern States
Cattle, occassionally horses and sheep.
Aromatic, furan ketones are present in all parts of the plant, but especially the flower and seed heads, and are readily absorbed from the digestive tract. Either directly or after bioactivation, the ketones are severly toxic to the type I pneumocytes in the lungs. This results in a proliferation of type II pneumocytes which rapidly fill the lungs and cause acute interstitial pneumonia that is frequently fatal.
Strong smelling, annual plants, often with purplish undersides to the leaves. The stems are erect, reaching 2-3 feet in height, branched or unbranched. As with all mints the stems are square. The leaves broadly ovate with acute tips, hairless, and purple on te underside. Flowers are racemes produced terminally on branches or in leaf axils. Petals ate purple to white.
Popular in Japanese cooking.
Nothing specific! Do not stress the animal as this accelerates death.
Acute respiratory difficulty, rapid open mouth breathing and death are common presenting signs. Often referred to as 'cow asthma'
At post mortem examination the lungs fail to collapse and have a 'meaty' consistency, with a glandular appearance on cut surface.
Pastures containing mint should not be grazed during the flowering stage.
Other species of mint are suspectd of causing similar signs in livestock.