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"Poisonous" does not mean deadly. Some manifestations of toxicity are subtle. The dose, as always, determines if a plant is safe source of nutrients or a toxic hazard.

General Effects of Astragalus Toxicosis

Congestive Heart Failure and Systemic Edema

Animals grazing at higher altitudes have a higher incidence of congestive heart failure, pulmonary and subcutaneous edema. James et al. (1984) speculated that this condition may be attributable to an alkaloid toxin (such as swainsonine) or due to nitro- compounds within the plants. In either case, it seems clear that there is some component of Astragalus which exacerbated the condition known as "high mountain disease", resulting in right side congestive heart failure. This condition from locoweed poisoning is most often seen in cows and especially in calves. High mountain disease is named as such because it has been associated with living in or visiting high altitudes. Evidence says that HMD is an hypoxia induced pulmonary hypertension. Hypertrophy of the right ventricle followed by heart failure occurs because of stress to the right ventricle, due to increased pulmonary vascular resistance. The usual signs and symptoms of HMD are weakness, depression, labored breathing, profuse dark fluid diarrhea, edema under the jaw/brisket, a bounding jugular pulse and unwillingness to move. The gross lesions associated with HMD are: right ventricular hypertrophy and dilation, subcutaneous edema, hydrothorax, ascites, edema of the mesenteries and chronic passive liver congestion.

Growth Retardation and Loss of Body Condition

Growth retardation and loss of body condition are non-specific effects from many sorts of intoxication. When an animal is in a compromised state, it will often eat less and/or have lower efficiency of feed utilization, resulting in slowed growth as well as emaciation (loss of body condition).

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