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There are 15 species of Rumex listed in Texas.
Most of these are perennial herbs with a basal rosette of
leaves. The stalk is upright and has alternate, mostly entire
(edges have no notches or indentations) leaves.
The small, greenish flowers are arranged in dense clusters
on elongated stems. The mature flowering stalk and the three-sided
fruit are usually brown at maturity. Each fruiting body contains
a single black or brown seed.
Distribution and habit
At least one species of dock can be found in each vegetational
area of Texas. It is among the most common weed across the
United States and southern Canada. Dock grows most often on
disturbed soil, and most Texas species are found in seasonally
wet areas.
Regions: 1, 2,
3, 4,
5, 6,
7, 8,
9, 10.
Toxic agent
Dock contains soluble oxalates, and the concentration tends
to increase as the plant matures. Poisoning is uncommon, but
occurs most frequently in ruminants. At a low level of intake,
the rumen microorganisms adapt over a period of several days
and are able to use oxalates to produce energy.
Toxicity can occur when nonadapted animals consume a large
amount of oxalate. In oxalate poisoning, calcium oxalate crystals
are deposited in the kidneys and in blood vessel walls.
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Livestock signs
Clinical signs of poisoned animals may include:
- Anorexia
- Incoordination
- Depression
- Prostration
- Convulsions
- Death
Severely poisoned animals that live for several
days can die from kidney failure.
Integrated management strategies
Good pasture or range management can prevent the sudden
intake of the large amount of dock necessary to produce
poisoning. Most cases of poisoning occur when these unpalatable
plants are treated with a herbicide such as 2,4-D without
removing the animals from the pasture. This treatment makes
the plant more palatable and may also increase its oxalate
content.
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