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Description
Rayless goldenrod is a low-growing half-shrub with erect stems
arising from a woody crown to a height of 2 to 4 feet. The
leaves are sticky, narrow, alternate and may be even or slightly
toothed along the margins. The stems bear flat-topped clusters
of yellow flowers from June through October.
Distribution and habitat
Rayless goldenrod is often found on dry rangelands, especially
in river valleys, along drainage areas and irrigation canals,
and on gypsiferous soil outcrops. It is a local problem in
the Pecos Valley drainage in southeastern New Mexico and western
Texas. It usually grows at 2,000 to 6,000 feet elevation and
is found from southern Colorado into Texas, Mexico, New Mexico
and Arizona.
Regions: 8, 9,
10.
Toxic agent
Goldenrod can poison all species of livestock. The toxic agent
is tremetone. The poison accumulates in the animal and is
present in green and dry leaves, making the plant toxic year-round.
The toxin in rayless goldenrod can be passed through milk.
It is common for poisoning signs to appear in suckling young,
but not their mothers. Humans have been poisoned by consuming
milk from affected cattle. Most poisoning cases occur in late
fall or early winter, but can occur year-round. A lethal dose
generally consists of 1.0 to 1.5 percent of the animal’s
weight, consumed over 2 to 3 weeks.
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Livestock signs
In cattle, this plant produces clinical signs often referred
to as the trembles. Muscular trembling is particularly noticeable
about the nose, hips and over the shoulders. Trembling is
more pronounced after exercise. Stiffness and weakness are
most pronounced in the forelegs. In later stages, the animal
lies down and becomes unable to rise. Other signs may include:
- Constipation
- Vomiting
- Quickened and labored breathing
- Almost continuous dribbling of urine
Shortly before death, the animal breathes
with a prolonged inhalation followed by a pause and then
a short and somewhat forcible expiration. Postmortem findings
in cattle include:
- Congestion of the abomasum and intestine
- Pale liver
- Distended gall bladder
Integrated management strategies
Keep animals away from areas severely infested with rayless
goldenrod. There is no specific treatment for poisoned
animals. Remove them from the area of poisoning and give
them good-quality hay and water. Purgatives and laxative
feeds may aid recovery. Orally administering activated
charcoal at 1 gram per kilogram of body weight may be
helpful. Take calves and lambs off poisoned mothers. Discard
all milk from affected females. Chemical control is achieved
through aerial or round broadcast methods in the fall.
Good results have come from applying 0.45 ounces a.i./acre
of Escort® or 0.5 pound a.i./acre of Tordon 22K®.
Treat individual plants with a 1.0 percent v/v solution
of Tordon 22K®.
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