Map of Selenium Status in US & Canada
This is a very
old map (Kubota et al., 1967). While the
areas showing deficient may still be correct I'm aware that there
have been other areas deficient in selenium that have beenidentified
in the last decade(s) that are not represented on this map. Please
in Counties of the Conterminous States
"Selenium deficiency is a major problem for livestock
or wildlife in at least 37 states and costs beef, dairy, and sheep producers
an estimated $545 million in losses every year. " soil
scientist Gary S. Bañuelos
selenium in the soil depends on the rocks from which the soil was derived.
The Northwest, Southeast, and Great Lakes states have low (<.05 ppm)
soil selenium concentrations because the soils in those areas were derived
from volcanic deposits or well-washed coastal deposits. Soils originating
from cretaceous shale, such as found in South Dakota, Montana, Wyoming,
Nebraska, Kansas, Utah, Colorado, and New Mexico, tend to have high (2
to 10 ppm) soil selenium concentrations.
Forms of selenium commonly
found in soils include: selenides, elemental selenium, selenites, selenates,
and organic selenium, for absorption by plants selenate and selenite are
the most available forms. Selenate and selenite are generally found in
alkaline, well-aerated soils. The insoluble selenide and elemental selenium
are the least available and are found in acidic, poorly aerated soils.
(Reference and sources -
Related Disorders in Washington Livestock N.L. Gates and K.A. Johnson,Washington
high levels of organic selenium will accumulate selenium in skeletal muscle.
Selenium is stored in muscle primarily as selenomethionine, a selenium
containing amino acid. Muscle serves as an important storage area for selenium.
In a study conducted in Canada, skeletal muscle selenium content was examined
in cattle from different geographic locations. Selenium deficient areas
produced beef with much lower selenium content than cattle produced on
seleniferous areas in Manitoba and Saskatchewan. A similar study tested
skeletal muscle selenium concentrations in ewes grazing forages with known
selenium content. These studies indicate that much of the variation of
selenium content of skeletal muscle can be attributed to selenium levels
in feed influenced by geographic location. The aforementioned studies correlate
to a generalized map of the United States and Canada showing selenium distribution
in crops (see above map).
[Reference & sources
: Korry J. Hintze, Graduate Student, Animal & Range Science Dept.,
NDSU, Fargo - Greg P. Lardy, Assistant Professor, Animal & Range Science
Dept., NDSU, Fargo - John W. Finley, Research Scientist, USDA Human Nutrition
Center, Grand Forks - 1998
Dakota State University * Dickinson Research Extension Center]
Additional references and
deficiency in cattle and other ruminants in California
and Livestock Metabolism, Toxicity, and Deficiency
Sulfur Amendments Suppress Selenium Uptake by Alfalfa and Western Wheatgrass
J., W.R. Allaway, D.L. Carter, E.E. Cary and V.A. Lazar. 1967. Selenium
in crops in the United States in relation to selenium-responsive diseases
of livestock. J. Agric. Food Chem. 15:448.Lakin, R.W., and D.F. Davidson.
1967. The relation of the biochemistry of selenium to its occurrence
in soils. Selenium in Biomedicine: A Symposium, Westport, CN: AVI.
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