HITS since April 5, 2000
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Seedling
Flower |
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Broad-leaf milkweed,
Common Milkweed
(Asclepias latifolia)
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More than 30 species of milkweeds have been recorded in Texas.
Broad-leafed milkweed is noted for its robust nature and leaf
size. A perennial, this plant has stout simple stems and four
or more pairs of large thick leaves no more than twice as long
as they are wide. The flowers are greenish to white, giving
rise to two to four smooth pods about 2 to 3 inches long from
July to October.
Distribution and habitat
Broad-leafed milkweed is most common along trails and roadsides,
less so in pastures. As with many weeds of low palatability,
this species increases in heavily grazed pastures. It is frequent
to abundant over much of the Trans-Pecos, the Plains and the
central and western Edwards Plateau of Texas. It is found
from Nebraska to Utah and west to Arizona.
Regions: 7, 8,
9, 10.
Toxic agent
This plant poisons cattle and goats, but more often sheep.
The toxic agents are cardiac glycosides. To be poisoned, cattle
can eat as little as 1.0 percent of their body weight in broad-leafed
milkweed; amounts as low as 0.15 percent have poisoned sheep
and goats. Broad-leafed milkweed is toxic in all growth stages,
but is most toxic when immature. Cattle can generally graze
frost-killed plants and not be poisoned.
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Livestock
signs
The signs produced by most species of Asclepias differ only
in degree. They include:
• First, profound depression, weakness and staggering
• Collapse, followed by frequent, intermittent muscular
tremors
• Labored respiration, elevated temperature and pupil dilation
• Death, after a comatose period of variable
duration
Signs appear within a few hours of ingestion of a toxic dose,
and death follows within a few days in most fatal cases.
Integrated management strategies
The best way to prevent losses from broad-leafed milkweed
is to maintain good range condition. Removing plants along
trails and in holding traps may prevent many losses, especially
when hungry livestock are being trailed. Avoid placing many
animals where infestations are severe and forage is limited.
Do not feed hay contaminated with milkweeds. Although no
medicinal treatment is specified, sedatives, laxatives and
intravenous fluids may help.
Printable
Version (PDF) 
  
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Send Comments to: Dr.
Charles Hart, Dr. Bruce Carpenter,
Dr. John Reagor , or Dr.
Allan McGinty.
This material is based upon work supported by the Cooperative
State Research, Education, and Extension Service, U.S. Department of Agriculture,
under a Southern Region IPM Program special project number 97-EPMP-1-0153.
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