Plants Poisonous to Horses

Not all parts of some poisonous plants are toxic.

• True

• False

Some poisonous plants are more toxic at certain times of the year and certain times of the day.

• True

• False

The time from eating a poisonous plant to the appearance of the first symptoms is always within 30 minutes after exposure.

• True

• False

Plants are classified according to their poisonous principles. These include alkaloids, glycosides, saponins, nitrates, oxalates, tannins, photo-dynamic substances, minerals phenols, volatile oils, etc. These are synthesized by a chemical process within the plant or concentrated by the plant from the soil. Many of these groups overlap chemically and other classifications are possible. The next section deals with these classifications.

• True (fact)

• True (fact)

Alkaloid containing plants are generally avoided by horses because they have a _________ taste.

• bitter

• sour

• salty

• sweet

What four main categories determine glycosides toxicity?

• cyanogenic (broken down the digestive system releasing the poisonous chemical, hydrocyanic acid aka cyanide)

• goitrogenic (inhibit the uptake of iodine by the body)

• cardiac (increases the contractions of the heart muscle while slowing the heart rate)

• saponic (forms a lather and emulsifies oils)

• all of the above

Other effects of cardiac glycosides include gastroenteritis and diarrhea.

• True

• False

Death can occur within 5 hours if lethal quantities of a cardiac glycoside are ingested and left undisturbed.

• True

• False

In cases of cardiac glycoside poisoning, surgical elimination of the plant from the system is usually the only option.

• True

• False

Saponins (saponic glycosides) are more toxic when injected than when eaten.

• True

• False