Animals that feed on sneezeweed may become affected with "spewing sickness". The disease gets its name from its most characteristic sign -- chronic vomiting or spewing. In the Western States, western sneezeweed is common to many mountain ranges. Sheep are frequently poisoned by sneezeweed; cattle are rarely poisoned. Animals eat sneezeweed during the summer and fall, when other forage is scarce or has become less palatable. All plant parts are poisonous.
Sneezeweed has one or several stems. Leaves are alternate, lance shaped, and smooth edged. Orange flowers with darker orange centers grow in clusters. Sneezeweed is a perennial of the sunflower family and is closely related to bitterweed and Colorado rubberweed
Where and When It Grows Sneezeweed grows at elevations of 1500 to 4,000 meters on moist slopes and well-drained meadows from western Montana and eastern Oregon southward to California and New Mexico. It starts growing in early spring and matures in the late summer and early fall. It generally is between 0.5 and 1.0 meters tall. Sneezeweed increases with range misuse. Heavy stands of sneezeweed will inhibit the growth of other plants.
How It Affects Livestock An animal may die if it eats small quantities of sneezeweed over a long period. Eating about 1 kg of green sneezeweed leaves daily for 10 days may poison sheep. Some animals die within a few days after first signs appear. Others that develop a chronic form of poisoning may live for 2 to 3 weeks. Complete recovery from the poisoning is possible if animals are taken off the plants as soon as the first signs are observed.
Signs and Lesions of Poisoning
Lips may become stained green from vomiting
Lambs may become stiff and wasted
Weakness with irregular pulse
Frothing at the mouth
Emaciation and wasting
Renal tubular necrosis
How to Reduce Losses
Alternate grazing of sneezeweed (on-and-off) in infested areas.
As soon as signs of poisoning appear, remove all animals from sneezeweed-infested range for 10 to 14 days. Lambs are good indicators as they usually show signs of stiffness before other symptoms appear in older sheep. Lambs left to graze sneezeweed after signs first appear become unthrifty and unprofitable to keep. Ewes left on sneezeweed after signs appear will waste and die.
Practice open herding, allowing animals free movement to select more desirable plants. Prevent overgrazing and forcing animals to eat sneezeweed due to lack of better forage. Improve range condition to reduce snakeweed density.
Sneezeweed can be controlled with 2,4-D at 4 lb/ac. Follow all precautions for handling herbicides.