Toxic Principle

Soluble potassium and sodium oxalates. Oxalis spp. poisoning is rarely a problem in North America, but has been associated with severe poisoning of livestock in Australia.

Description

Herbaceous animals or perennials that grow horizontally but occasionally erect with characteristic alternate or basal leaves that are palmately 3-foliate and obcordate in shape. The flowers are usually yellow, with perfect stipules, and regular umbel-like or dichotomous cymes. The fruit is a capsule.

Musculoskeletal

Muscle tremors, tetany, weakness, reluctance to move, depression, and recumbency resulting from hypocalcemia and hypomagnesemia. Coma and death may result within 12 hours. Animals that survive the acute effects of oxalate poisoning frequently develop kidney failure.

Treatment

Calcium gluconate, magnesium sulfate, glucose, and a balanced electrolyte solution can be given intravenously to maintain kidney perfusion, and treat the effects of the low blood calcium. Giving limewater [Ca(OH)2] orally will help to prevent absorption of further soluble oxalate from the rumen. The prognosis is usually very poor because of the severe kidney damage that results.

Renal System

Animals that survive the acute effects of oxalate poisoning frequently develop kidney failure. Insoluble calcium oxalate filtered by the kidneys causes severe damage to the kidney tubules. Animals die from renal failure.

Diagnosis

Hypocalcemia, oxalate crystals in the urine, and evidence of oxalate nephropathy histologically.

Special Notes

Wood sorrels can form a dense carpet of plants that are potentially dangerous to livestock that may graze them when other forages are not available.