Chokecherry is a perennial that bears masses of white flowers in long clusters in the spring. Small ripe cherries range in color from purple to black. Leaves are dark green and glossy.
Western chokecherry and black chokecherry cause livestock poisoning when drought and overgrazing reduce the availability of grasses and other forage. Animals become poisoned if they eat large quantities of the leaves in a short time. Both sheep and cattle may be poisoned by chokecherry. Although most losses occur when feed is scarce, a few animals seem to prefer this plant to other forage. Cattle sometimes are poisoned by eating leaves on branches trimmed from cultivated chokecherry trees. The toxic substance in chokecherry, hydrocyanic acid, is found principally in the leaves. Leaves become less toxic as the growing season advances.
Chokecherry and arrowgrass both contain hydrocyanic acid. Other plants with cyanogenic potential include Sudan grass, Johnson grass, reed canary grass, white clover, birdsfoot trefoil, mountain mahogany, and Saskatoon service berry.
Where and When It Grows Chokecherry grows in damp and fertile soil. It is found in thickets on hillsides and canyon slopes. It appears as a shrub or small tree among willows, poplars, and alders that grow along mountain streams. Chokecherry begins growing early in the spring. Its growth is slow at high elevations.
Chokecherry trees may reach a height of 20 feet. They are often found growing with other trees and bushes. The berries are not considered to be toxic and are often used in jelly and syrups. Chokecherry may grow as a shrub to about 4 feet in height. It is found in thickets, along hillsides, and on canyon slopes.
How It Affects Livestock Although the hydrocyanic acid content of chokecherry leaves varies, ingestion of about 0.25 percent of an animal's weight in leaves can be fatal. Wilted leaves, as well as fresh leaves, are poisonous. Poisoning occurs when an animal consumes a relatively large amount over a short period of time (30-60 minutes). Hydrocyanic acid inhibits cellular respiration and the animal's ability to use oxygen. Signs of poisoning begin rapidly, and death may follow within a few minutes.
Signs and Lesions of Poisoning
Death (animals consuming large amounts of this plant may die within 60 min and show only convulsions and death as signs of poisoning)
Distress, rapid breathing and gasping
Blood and tissues may be cherry red and blood may clot slowly
Salivation, excitement and anxiousness, muscular twitching, staggering, and convulsions that may progress to coma
Bloat may occur; rumen contents may have odor of almonds
Tracheal and pulmonary congestion possibly with small hemorrhages
How to Reduce Losses Keep hungry or thirsty animals off areas where chokecherry is abundant. The action of hydrocyanic acid is so rapid that it is usually too late to treat an affected animal after the signs are recognized. However, if treated immediately, some poisoned animals may be saved. Suggested treatment includes intraperitoneal or intravenous injection of a mixture of 20 ml of a 10% solution of sodium thiosulfate and 10 ml of a 10% solution of sodium nitrite. For animals in advanced stages of poisoning, an intravenous treatment is essential. Do not let animals become overexcited while they are being treated. For advice about treatment, consult your local veterinarian.
Control of chokecherry is not practical on a large scale. However, several herbicides are effective. Follow all precautions for handling herbicides