VALUE AND USE
SPECIES: Oxytropis sericea | Whitepoint Locoweed 



WOOD PRODUCTS VALUE : 
NO-ENTRY


IMPORTANCE TO LIVESTOCK AND WILDLIFE : 
Livestock:  Whitepoint locoweed causes locoism in all classes of
livestock [12,36].  The toxin in locoweed is an indolizidine alkaloid,
swainsonine, that causes chronic neurological damage [29].  Livestock
must consume large amounts of whitepoint locoweed for 1 to 3 months
before death occurs.  Signs of poisoning will appear after 2 to 3 weeks
of continuous grazing [36].  Symptoms are as follows:  rough coats,
nervous disorders such as trembling and paralysis, uncoordinated muscle
movements, blindness, constipation, and emaciation [34].

Most cattle will readily graze whitepoint locoweed in the spring when
grass is scarce.  Sheep and cattle can become chemically addicted to
whitepoint locoweed and will continue to graze it when grass becomes
abundant.  They are, however, more resistant than horses to its toxic
effects [16,22].  Horses never recover once poisoned.  Cattle gain
weight slowly and often have abortions, while sheep have a high number
of abortions after grazing whitepoint locoweed [43].

On high mountain ranges, whitepoint locoweed has been identified as a
predisposing factor in high mountain brisket disease, or congestive
right-sided heart failure, in cattle [22,26].

Wildlife:  Whitepoint locoweed is poisonous to deer and elk if consumed
in large quantities [36].  Whitepoint locoweed is a minor component in
the diet of desert cottontails.  Greatest utilization is in the spring
and summer, when whitepoint locoweed is the most succulent [9].


PALATABILITY : 
Immature whitepoint locoweed seed pods are palatable and voluntarily
selected by free-ranging cattle during the normal grazing season [22].
The reproductive heads of locoweed are preferred and readily consumed
even when other forage species are abundant [29].

Palatability ratings for whitepoint locoweed from selected western
states are as follows [3]:

                      WY       UT       CO       MT
cattle               fair     poor     poor     poor
sheep                fair     fair     poor     fair
horses               fair     poor     poor     fair
elk                  fair     poor     ----     ----
mule deer            good     poor     ----     fair
white-tailed deer    ----     good     ----     ----
pronghorn            fair     poor     ----     ----
upland game birds    poor     poor     ----     ----
waterfowl            ----     poor     ----     ----
small nongame birds  poor     poor     ----     ----
small mammals        ----     poor     ----     ----


NUTRITIONAL VALUE : 
All parts of whitepoint locoweed plants are toxic, and plants are
poisonous at all stages of growth.  It loses little toxicity after 3
years of storage [36].  Swainsonine inhibits the enzyme
alpha-mannosidase which is essential in the metabolism of glycoproteins
[22].

Relative magnitude of alkaloid concentration and nutrients (percent of
dry weight) in whitepoint locoweed are as follows [29]:

                              Bloom     Immature Pod     Mature Pod
                                     week of grazing season 
                                0        2          4         7
nutrient       loco part

alkaloid         head         high    moderate    moderate   high
                 leaf         low     low         low        low
crude protein    head         17.3    17.3        17.4       16.4
                 leaf         12.9    12.1        11.8       11.1
fiber            head         26      38          41         40
                 leaf         32      36          36         36
water            head         65      60          57         43
                 leaf         69      65          65         51

In a study in northwestern Utah. percent of loco heads (flowers and
pods) grazed was 26 percent after the first 2 weeks of the grazing
season and increased to 69 percent by the end of the 7-week grazing
season [26].

Energy value and protein value for whitepoint locoweed are poor [3].


COVER VALUE : 
NO-ENTRY


VALUE FOR REHABILITATION OF DISTURBED SITES : 
NO-ENTRY


OTHER USES AND VALUES : 
NO-ENTRY


MANAGEMENT CONSIDERATIONS : 
Locoweed poisoning of livestock is the most widespread poisonous plant
problem in the western United States [26].  Whitepoint locoweed
increases in abundance in response to excessive grazing [16].  When
there is a shortage of palatable, nonpoisonous forage, animals will
consume more locoweed [34].  Eradication of whitepoint locoweed over
large areas is seldom possible.  Vegetation manipulation should be
integrated with livestock management programs that minimize the intake
of whitepoint locoweed [16].  Aversive conditioning of livestock to
avoid whitepoint locoweed may be effective in reducing livestock losses
[29].  A three-herd, four-pasture rotation system that involves grazing
animals for 6 weeks to 2 months in July and August has reduced the risk
of whitepoint locoweed intoxication in the Raft River Mountains of Utah
[31].

Selective herbicide control may be necessary to reduce whitepoint
locoweed [29].  Picloram, dicamba, and 2,4-D are effective on whitepoint
locoweed if sprayed when plants are actively growing in early summer
before they reach the bud stage [43].  An ester of 2,4-D was sprayed on
whitepoint locoweed on a rangeland in northwest Utah in 1969.
Whitepoint locoweed established to pretreatment levels by 1978 [26].
When aerially sprayed with 2,4-D in 1981, all plants were killed on
deeper soils, but some remained on shallower soils [26].

Whitepoint locoweed fixes atmospheric nitrogen.  It has potential to add
significant amounts of nitrogen to forest sites in the Inland Northwest
because of its nitrogen-fixing ability [13].  However, whitepoint
locoweed seedlings compete with conifer tree seedlings on many sites
[13].
 

Related categories for Species: Oxytropis sericea | Whitepoint Locoweed