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Notes on poisoning: alfalfa


General poisoning notes:

Alfalfa (Medicago sativa) is an important forage and silage crop in Canada. However, under some circumstances, alfalfa can cause a variety of different toxic problems. Ingesting rapidly growing alfalfa at the vegetative to mid-bud stage can cause bloat in cattle and sheep (Hall and Majak 1989). Alfalfa has also caused photosensitization in cattle with white skin (MacDonald 1954). Alfalfa contains phytoestrogens which cause infertility in animals, including cattle and sheep. These compounds are also contained in some alfalfa pills that are found in health food stores, and these may cause problems in some cases (Cheeke and Schull 1985). Alfalfa also contains saponins that can interfere with the growth of poultry and thus reduce egg-laying (Fuller and McClintock 1986, Oakenfull and Sidhu 1989). Low saponin cultivars have been developed.

References:

Adams, N. R. 1989. Phytoestrogens. Pages 23-51 in Cheeke, P. R., ed. Toxicants of plant origin. Vol. IV. Phenolics. CRC Press, Inc., Boca Raton, Fla., USA. 232 pp.

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

Fuller, T. C., McClintock, E. 1986. Poisonous plants of California. Univ. California Press, Berkeley, Calif., USA. 432 pp.

Hall, J. W., Majak, W. 1989. Plant and animal factors in legume bloat. Pages 93-106 in Cheeke, P. R., ed. Toxicants of plant origin. Vol. III. Proteins and amino acids. CRC Press, Inc., Boca Raton, Fla., USA. 271 pp.

MacDonald, H. E. 1954. Photosensitization. Can. J. Comp. Med., 18: 228.

Oakenfull, D., Sidhu, G. S. 1989. Saponins. Pages 97-143 in Cheeke, P. R., ed. Toxicants of plant origin. Vol. II. Glycosides. CRC Press, Inc., Boca Raton, Fla., USA. 277 pp.

Nomenclature:

Scientific Name: Medicago sativa L.

Vernacular name(s): alfalfa

Scientific family name: Leguminosae

Vernacular family name: pea

Go to ITIS*ca for more taxonomic information on: Medicago sativa

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
British Columbia
Manitoba
New Brunswick
Northwest Territories
Nova Scotia
Ontario
Prince Edward Island
Quebec
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

alfalfa:

Images: images.google.com

Toxic parts:

leaves
stems

References:

Fuller, T. C., McClintock, E. 1986. Poisonous plants of California. Univ. California Press, Berkeley, Calif., USA. 432 pp.

Notes on Toxic plant chemicals:

Alfalfa contains two phytoestrogenic compounds, coumestrol and coumestan. These compounds can cause fertility problems in sheep and cattle. Alfalfa also contains bloat-causing proteins. Saponins, such as medicagenic acid, can cause growth reduction in poultry (Adams 1989, Hall and Majak 1989, Oakenfull and Sidhu 1989).

Toxic plant chemicals:

coumestan
coumestrol
Image of coumestrol

medicagenic acid
Image of medicagenic acid

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

References:

Adams, N. R. 1989. Phytoestrogens. Pages 23-51 in Cheeke, P. R., ed. Toxicants of plant origin. Vol. IV. Phenolics. CRC Press, Inc., Boca Raton, Fla., USA. 232 pp.

Fuller, T. C., McClintock, E. 1986. Poisonous plants of California. Univ. California Press, Berkeley, Calif., USA. 432 pp.

Oakenfull, D., Sidhu, G. S. 1989. Saponins. Pages 97-143 in Cheeke, P. R., ed. Toxicants of plant origin. Vol. II. Glycosides. CRC Press, Inc., Boca Raton, Fla., USA. 277 pp.

Animals/Human Poisoning:

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

Cattle

General symptoms of poisoning:

bloat
infertility

Notes on poisoning:

Cattle are especially susceptible to bloat after ingesting rapidly growing alfalfa in the vegetative to mid-bud stage of growth. The formation of stable foam bubbles is recognized as being affected by the concentration of cytoplasmic proteins, which is in turn affected by rumen pH, and the colloidal suspension of chloroplast particles from the plant; the stability is controlled by ion concentration (Hall and Majak 1989). Alfalfa also contains phytoestrogens, which have caused infertility problems in dairy cattle because of cystic ovaries and irregular estrous cycles. Precocious development of mammary glands also occurs, as well as genital formation in heifers. The coumestan chemicals suppress estrous and inhibit ovulation (Cheeke and Schull 1985, Adams 1989).

References:

Adams, N. R. 1989. Phytoestrogens. Pages 23-51 in Cheeke, P. R., ed. Toxicants of plant origin. Vol. IV. Phenolics. CRC Press, Inc., Boca Raton, Fla., USA. 232 pp.

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

Fuller, T. C., McClintock, E. 1986. Poisonous plants of California. Univ. California Press, Berkeley, Calif., USA. 432 pp.

Hall, J. W., Majak, W. 1989. Plant and animal factors in legume bloat. Pages 93-106 in Cheeke, P. R., ed. Toxicants of plant origin. Vol. III. Proteins and amino acids. CRC Press, Inc., Boca Raton, Fla., USA. 271 pp.

Chickens

General symptoms of poisoning:

weight gain, reduced

References:

Oakenfull, D., Sidhu, G. S. 1989. Saponins. Pages 97-143 in Cheeke, P. R., ed. Toxicants of plant origin. Vol. II. Glycosides. CRC Press, Inc., Boca Raton, Fla., USA. 277 pp.

Humans

General symptoms of poisoning:

infertility

Notes on poisoning:

Alfalfa tablets are available in health food stores as a dietary supplement for humans. The benefits of the tablets are not clear. Measurements of the phytoestrogen content of some commercial brands have ranged from 20 to 190 ppm. This level of intake, in conjunction with other sources of estrogen (such as birth control pills and estrogen replacement therapy), may be potentially harmful (Cheeke and Schull 1985).

References:

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

Sheep

General symptoms of poisoning:

bloat
erythema
infertility
skin, peeling of

References:

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

MacDonald, H. E. 1954. Photosensitization. Can. J. Comp. Med., 18: 228.

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Date modified: 2009-09-01