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Perennial broomweed or broom snakeweed is a short-lived, perennial
half-shrub ranging from 6 inches to about 2 feet tall. Many
unbranched, erect stems originate from a woody base and die
back when the plant goes dormant. The leaves are narrow and
threadlike. The small yellow flowers are clustered at the branch
tips from June to October.
Distribution and habitat
Perennial broomweed is wide-spread on dry ranges and deserts
from California to Texas, south to Mexico and north to Idaho.
Extreme infestations reduce forage production but may not
indicate overgrazed ranges because broomweed populations fluctuate
naturally. However, overgrazing does accelerate the plants
growth and propagation.
Regions: 2, 3,
4, 5,
6, 7,
8, 9,
10.
Toxic agent
Perennial broomweed poisons cattle, sheep, goats and swine.
Some believe the toxic agent is a steroidal saponin. The plant
may accumulate selenium when on high selenium soil. Perennial
broomweed is most toxic at earlier growth stages, usually
in late winter or early spring and on sandy soils. It is relatively
nontoxic growing on clay soils. Cattle abort after eating
as little as 20 pounds of fresh broomweed in 7 days. Cattle,
sheep and goats have been killed by eating 10 to 20 percent
of their body weight in peren-nial broomweed over 2 weeks.
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Livestock
signs
Chronic poisoning signs in-clude:
Abortion
Stillbirth
Retained placenta
Weak offspring
Acute poisoning signs include:
Periodic, thick nasal discharge
Crusting and sloughing of the skin of the
muzzle
Listlessness
Loss of appetite and weight
Rough hair coat
Occasionally, dark brown or reddish urine
Frequent urination with diarrhea in the early stages changes
to constipation with large amounts of mucous. Pregnant cows
often have periodic vulvar swellings and premature udder development.
Integrated management strategies
Do not graze gestating livestock on sandy soils during maximum
perennial broomweed growth (late winter and early spring).
Proper range management practices that improve range condition
may help limit perennial broomweed population densities
and livestock consumption. Carefully watch pregnant cattle
grazing perennial broomweed-infested pastures. If udders
develop prematurely, vulvas swell or abortions occur, move
the herd to a perennial broomweed-free pasture. Chemical
control may be costeffective when populations are dense
enough to reduce forage production. Herbicide treatments
for perennial broomweed include aerial or ground broadcast
applications of Escortฎ at 0.0625 ounce a.i./acre in the
spring when weeds are less than 4 inches high. Tordon 22Kฎ
may be used during and after full flower stage in the fall
at 0.25 to 0.5 pound a.i./acre. To reduce reinfestation,
follow chemical treatments with proper range and livestock
management programs.
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