False hellebore, or veratrum (sometimes called wild corn or cow cabbage), is a range plant that causes severe poisoning in sheep. It also affects cattle and goats. If ewes, nanny goats, and cows eat it during early pregnancy, false hellebore causes deformities in the offspring. Sheep and goats readily eat leaves and plant tops. Cattle may eat it if other forage is scarce.
False hellebore is poisonous from the time it starts to grow until after it is killed by freezing, but toxicity decreases as plants mature. The roots are 5 to 10 times as poisonous as leaves or stems. The poisonous substances in false hellebore are steroidal alkaloids. False hellebore grows in damp or seepage areas, on meadows, and on hillsides. The plant reaches a height of 1.5 to 2 meters. It is a robust perennial of the lily family.
Leaves of false hellebore may measure 20 to 30 cm long and 7 to 15 cm broad. Cream-colored flowers grow in clusters at the top of a single unbranched stalk in a way that resembles corn. Seed pods turn black as they ripen.
Where and When It Grows
False hellebore grows on moist, open meadows and hillsides at elevations of 1500 to 4000 meters. It emerges as soon as snow melts in the spring. Flowers appear in July and August, and the plant produces seeds in September.
How It Affects Livestock
False hellebore poisoning may occur in 2 to 3 hours after an animal eats the plant. Sheep may show slight or marked signs of poisoning after eating 150 to 300 grams of green stems or leaves. If pregnant ewes eat false hellebore on the 14th day after breeding, the young may have congenital deformities of the head. These offspring, commonly called monkey-faced lambs, may have a protruding lower jaw, underdeveloped upper jaw, proboscis-like nose, cyclopia, hydrocephaly, and a variety of other deformities of the eyes. When ewes eat the plant between days 17-19, they give birth to lambs having tracheal stenosis. Ewes consuming veratrum between days 28-31 give birth to lambs having shortened metatarsal and metacarpal bones. Ewes carrying severely deformed fetuses may fail to lamb at the end of the normal gestation period. The fetus thus continues to grow to an abnormal size and eventually may kill the ewe unless the lamb is delivered by caesarian surgery. Sheep poisoned on veratrum can be successfully treated with epinephrine.
Signs of Poisoning
Excessive salivation with frothing
Fast, irregular heartbeat
Slow, shallow breathing
How to Reduce Losses
Losses of newborn animals from deformities can be avoided by keeping sheep, goats, and cattle away from false hellebore during early gestation.
False hellebore may be controlled by applying amine salts of 2,4-D at the rate of 1 kg per acre of acid equivalent after the last leaves have expanded and before bud stage. A second treatment may be required the following year. Follow all precautions for handling herbicides.