General poisoning notes:

Two-grooved milk-vetch (Astragalus bisulcatus) is a native plant found on rangelands in western Canada. This plant can accumulate quantities of selenium high enough to cause toxicity in cattle, horses, sheep, and swine. High quantities of selenium cause acute toxicity, with symptoms including staggering, diarrhea, prostration, and abdominal pain. Plants that contain a selenium content of less than 200 ppm cause chronic toxicity. James et al.(1983) used this plant (selenium content of 180 ppm) to conduct feeding experiments on sheep. They found that the symptoms and microscopic lesions of tissues collected from the sheep were similar to those caused by locoweed poisoning and not selenium poisoning. This finding suggests that other toxic compounds in addition to selenium may be present.

Swainsonine is also found in this plant, which may explain why, in experiments, sheep exhibited symptoms more appropriate to locoism than to selenium poisoning (Cheeke and Schull 1985).

References::

Baker, D. C., James, L. F., Panter, K. E., Mayland, H. F., Pfister, J. A. 1987. Selenosis in developing pigs fed selenium from different sources. Am . Soc. Anim. Sci. Abstr., 65: 351.

Cheeke, P. R., Shull, L. R. 1985. Natural toxicants in feeds and poisonous plants. AVI Publishing Company, Inc., Westport, Conn., USA. 492 pp.

James, L. F., Van Kampen, K. V., Hartley, W. J. 1983. Astragalus bisulcatus--a cause of selenium or locoweed poisoning? Vet. Hum. Toxicol., 25: 86-89.

Nomenclature:

Scientific Name: Astragalus bisulcatus (Hook.) A. Gray
 

Vernacular name(s): two-grooved milk-vetch

Scientific family name: Leguminosae

Vernacular family name: pea

Go to ITIS*^ca for more taxonomic information on: Astragalus bisulcatus

References:

Agriculture Quebec. 1975. Noms des maladies des plantes du Canada/ Names of plant diseases in Canada. , Quebec City, Que., Canada. 288 pp.

Alex, J. F., Cayouette, R., Mulligan, G. A. 1980. Common and botanical names of weeds in Canada/Noms populaire et scientifiques des plantes nuisibles du Canada. Revised. Agric. Can. Publ., Ottawa, Ont., Canada. 132 pp.

Bailey, L. H., Bailey, E. Z. 1976. Hortus third. Revised. MacMillan, New York, N.Y., USA. 1290 pp.

Scoggan, H. J. 1978, 1979. The flora of Canada. Nat. Mus. Nat. Sci. (Ottawa) Publ. Bot. 7(1)-7(4). 1711 pp.

Van Wijk, H. L. 1911. A dictionary of plant names. Martinus Nijhoff, The Hague, The Netherlands. 1444 pp.

Victorin, M. 1964. Flore Laurentienne. 2nd ed. Univ. Montreal, Montreal, Que., Canada. 952 pp.

Geographic Information

Alberta
Manitoba
Saskatchewan
 

References:

Bailey, L. H., Bailey, E. Z. 1976. Hortus third. Revised. MacMillan, New York, N.Y., USA. 1290 pp.

Boivin, B. 1966, 1967. Énumération des plantes du Canada. Provencheria 6. Nat. Can. (Que.) 93: 253-274; 371-437; 583-646; 989-1063. 94: 131-157; 471-528; 625-655.

Image or illustration

two-grooved milk-vetch:

Images: images.google.com

Toxic parts:

flowers
leaves
stems
 

References:

James, L. F., Van Kampen, K. V., Hartley, W. J. 1983. Astragalus bisulcatus--a cause of selenium or locoweed poisoning? Vet. Hum. Toxicol., 25: 86-89.

Notes on Toxic plant chemicals:

This plant is a recognized selenium accumulator. Selenium has been found to be toxic to sheep and cattle at levels of 4-5 mg/kg of dry matter. Two-grooved milk-vetch collected in Canada contained selenium at 43 mg/kg, well above the level required for toxicity (Davis 1986).

Toxic plant chemicals:

selenium
swainsonine

Chemical diagram(s) are courtesy of Ruth McDiarmid, Biochemistry Technician, Kamloops Range Station, Agriculture and Agri-Food Canada, Kamploops, British Columbia, Canada.

References:

Cheeke, P. R., Shull, L. R. 1985. Natural toxicants in feeds and poisonous plants. AVI Publishing Company, Inc., Westport, Conn., USA. 492 pp.

Davis, A. M. 1986. Selenium uptake in Astragalus and Lupinus species. Agron. J., 78: 727-729.

Animals/Human Poisoning:

Note: When an animal is listed without additional information, the literature (as of 1993) contained no detailed explanation.

Cattle

Horses

Sheep

General symptoms of poisoning:

ascites
brain, vacuolation of
coat, rough and dry
cytoplasm vacuolation
depression
fetus, dead
kidney, vacuolation of
 

References:

James, L. F., Van Kampen, K. V., Hartley, W. J. 1983. Astragalus bisulcatus--a cause of selenium or locoweed poisoning? Vet. Hum. Toxicol., 25: 86-89.

Swine