Common Name
Curly leafed dock, sorrel, Winged Dock
Botanic Name
Rumex crispus L. Rumex venosus Pursh
Plant Family
Common plant of sandy soils of pastures, plains, and roadsides. Tends to be invasive in disturbed or overgrazed areas.
Animals Affected
Sheep, Cattle, and horses
Toxic Principle
Soluble oxalates rapidly combine with serum calcium and magnesium, causing a sudden drop in soluble serum calcium and magnesium. In the acute phase of oxalate poisoning the sudden decline in serum calcium impairs normal cell membrane function, causing animals to develop muscle tremors, weakness, collapse and death. In chronic oxalate poisoning, insoluble calcium oxalate filtered by the kidneys causes severe damage to the kidney tubules. Oxalates also interfere with cellular energy metabolism. Livestock poisoning from eating curly leaf dock is relatively rare. Cattle would need to eat considerable quantities of the plant to be affected (10-20 lbs of green plant for an adult cow.)
Perennial weed from a stout tap root. Stems may reach 100 cm without axillary branches. Leaves are 10-30 cm long, oblong to linear-lanceolate with crisped, wavy margins. An ocrea is present at the base of each petiole. The flower is a compound raceme or panicle having many small perfect or unisexual flowers. The perianth is six-parted with the inner three segments becoming the wings of the fruit. The inflorescence turns a dark red-brown when dry.
Excess salivation
Within a few hours of consuming toxic levels of oxalates, muscle tremors, tetany, weakness, reluctance to move, depression, and recumbency result from hypocalcemia. Coma and death may result within 12 hours.
Intravenous calcium gluconate, magnesium sulfate, glucose, and a balanced electrolyte solution to maintain kidney perfusion may be helpful early in acute oxalate poisoning. Giving limewater [Ca(OH)2] orally will help prevent absorption of further soluble oxalate.
Renal System
If animals do not die from the acute effects of the low blood calcium levels, death results from kidney failure.
The demonstration of calcium oxalate crystals in the kidneys and rumen epithelium histologically is diagnostic of oxalate poisoning. At necropsy, perirenal edema may be evident.
Special Notes
It is helpful to ensure livestock have an adequate balanced Calcium : Phosporus (1:1 ratio)as a mineral supplement to counter the effects of a diet high in oxalates. (1) Panciera RJ, Martin T, Burrows GE, Taylor DS, Rice LE. Acute oxalate poisoning attributable to ingestion of curly dock (Rumex crispus) in sheep. J Am Vet Med Assoc. 1990 Jun 15;196(12):1981-4. PMID: 2365622. (2) Dickie CW, Hamann MH, Carroll WD, Chow FH. Oxalate (Rumex venosus) poisoning in cattle. J Am Vet Med Assoc. 1978 Jul 1;173(1):73-4. PMID: 670054.