Amelanchier alnifolia, (A. humilis): Amelanchier alnifolia (Nutt.) Nutt. ex M. Roem.
Frequent in mountain valleys, open prairie ravines, lakeshores, and open woodlands. Often grows with chokecherry.
Cattle, sheep, goats
Cyanogenic glycosides which are readily hydrolysed by rumen bacteria to free hydrogen cyanide (HCN). All parts of the plant contain the cyanogenic glycosides except the ripe berries. The wilted leaves are more toxic than when fresh. The cyanide blocks the action of the cellular enzyme cytochrome oxidase thereby preventing hemoglobin from releasing oxygen to the tissues. Death results rapidly from anoxia.
Perennial, shrubs to small trees 3-12 feet tall. Leaves are alternate, longitudinally folded, apically rounded, sometimes serrate, deciduous. Flowers are produced in terminal, upright racemes often before the leaves. Flowers are white with 5 sepals and 5 petals. Fruits turn purple when ripe and are edible.
Without stressing the animal, sodium thiosulfate and sodium nitrite should be given intravenously. A mixture of 1ml 20% sodium nitrite and 3ml of 20% sodium thiosulfate should be prepared and given at the rate of 4 ml of the mixture per 100lbs body weight. Sodium thiosulfate should be given orally via stomach using 30gm dissolved in a gallon of water.
Mucous membranes appear pink and redder than normal. Venous blood is cherry-red in color. Stressing the animal rapidly leads to collapse and death.
Sudden death. If observed early in the course of poisoning, affected animals show difficulty in breathing. Open mouth breathing is common as the animal becomes oxygen deprived.
Excitment and nervousness result from the animal's rapidly developing anoxia.
Pregnant animals may abort if they survive the cyanide poisoning themselves.
Rumen contents or plant material can be tested for cyanide using the sodium picrate test. Commerical test kits for cyanide are available.
Stegelmeier BL, Davis TZ, Clayton MJ. Plants Containing Urinary Tract, Gastrointestinal, or Miscellaneous Toxins that Affect Livestock. Vet Clin North Am Food Anim Pract. 2020 Nov;36(3):701-713. doi: 10.1016/j.cvfa.2020.08.006. PMID: 33032700.