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Poisonous Trees

July 9th, 2012 · 1 Comment

By Clif Little
OSU Extension Agriculture/Natural Resources
Guernsey & Noble Counties

Recent storms downed many trees throughout Ohio, some of these pose a threat to livestock. Poisoning is most common when grazing is scarce, such as periods of dry weather coupled with thunderstorms that down trees during the mid to late summer months.

Among the most deadly this time of year is the wild black cherry. The leaves and twigs of fallen wild black cherry trees are readily eaten by livestock and are potentially deadly. The seeds, twigs, bark and leaves of the wild black cherry contain a highly toxic compound, hydrocyanic acid. Poisonings occur most often occur when wilted leaves are eaten, but can also occur when leaves are consumed fresh, or dry. Cyanide poisoning causes a deficiency of oxygen reaching the body tissues. Symptoms following consumption appear quickly. Animals may exhibit excitement, incoordination, convulsions, rapid and labored breathing. Consult your veterinarian immediately if you suspect poisoning. Wild black cherry trees should be among the first to be removed from livestock grazing lands.

​Red maple poisoning can result from livestock consuming wilted leaves of fallen trees. Dried leaves have been reported to remain toxic for up to thirty days. The cause of toxicity is not clearly understood however, the primary effects are acute hemolytic anemia, methemoglobinemia, and Heinz body formation in the red blood cells. Symptoms develop three to four days after ingestion and may include rapid breathing and heart rate, weakness, depression, cyanosis and brownish discoloration of blood and urine.
​The black locust tree contains several toxic compounds found in the sprouts, leaves, bark, flowers, and seed pods including a glycoside (robitin) and phytotoxins (robin and phasin). Affected animals may exhibit signs of depression, diarrhea, weakness, posterior paralysis, pupil dilation, weak pulse and rapid, irregular heartbeat.
​Many oak species contain toxic tannins. Large quantities of young leaves, sprouts and green acorns are toxic. Livestock must consume large quantities of these plant parts for a period of time before poisoning will occur. These plant tannins or their metabolites may cause intestinal and renal dysfunction. Symptoms appear several days after the period of consumption and include abdominal pain, depression, diarrhea and blood in urine.

​Our state tree the buckeye tree can and does make cattle sick each year. Cattle readily consume fallen buckeyes. Toxicity is attributed to glycosides and possibly alkaloids. Sprouts and leaves may also be poisonous. Animals exhibit depression, incoordination, twitching, paralysis and inflammation of mucous membranes. If caught quickly treated animals usually survive.
​As we clean up from the storm, some people mistakenly throw branches and clippings in to pastures. One of the most deadly shrubs to livestock is the yew. Yews are flat needled evergreen shrubs, with a bright red fleshy cup-shaped berry. The leaves bark, and seeds contain alkaloids that affect the nervous system and are toxic green or dry. Poisonings often occur when clipping are accessible to livestock. Symptoms include gaseous distress, tremors, diarrhea, convulsions, dilated pupils, weakness and respiratory difficulty.

​Combine summer drought with high winds and broken trees and we have the perfect storm for livestock poisoning. Clean pastures and hay fields of these potentially harmful trees. Provide additional feed and or hay when forage grazing is limited and consult your veterinarian if you suspect poisoning.

Tags: Grazing · Health · Management

1 response so far ↓

  • 1 Zane Lemon // Apr 2, 2013 at 3:36 pm

    Thanks. I appreciate it.

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