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MB Article - Georgia Horse Owners Advised of Toxic Weed in Alfalfa Hay

Georgia Agriculture Commissioner Tommy Irvin is alerting horse owners to a problem that has occurred with some alfalfa hay coming out of Michigan and the upper Midwest.

The hay may contain hoary alyssum (Berteroa incana), a weed that is toxic to horses.

"We have a report of 25 horses sickened from eating alfalfa hay from Michigan that contained this plant," Irvin said.  "The horses had swollen legs, fever and some were even foundering.

"What is especially troubling is that the alfalfa hay looked perfect.  The weed was practically invisible in the hay.  It was only upon close investigation after the horses got sick that the presence of this plant was found," the Commissioner said.
Hoary alyssum has round stems and an alternate leaf pattern.  (The leaves are not directly opposite each other but appear alternately up the stem.)  Because the dried leaves are fragile, most of them will have fractured and become part of the alfalfa "dust" in the bale.  The older stems may have a purple blush.  Stems may have a slight fuzz or "hoary" appearance. 

"I urge all horse owners in Georgia to check their alfalfa hay and to contact their veterinarian if they see any problems with their horses," Irvin said.  Hoary alyssum is not present in hay grown in Georgia; the weed is native to Europe and naturalized throughout much of the northern U.S.

For more information, horse owners can refer to "Hoary Alyssum: Toxicity to Horses, Forage Quality and Control" from the University of Minnesota at: www.extension.umn.edu/distribution/livestocksystems/DI5567.html.

Information and pictures of hoary alyssum also are available on the Georgia Department of Agriculture website www.agr.state.ga.us.
In addition, Dr. Dennis Hancock, an Extension forage specialist at the University of Georgia, has agreed to assist in identifying the weed in hay purchased from the northern U.S.

Clear digital photos of the stems and flowers can be e-mailed to dhancock@uga.edu.  Alternately, a large sample of suspect hay can be placed in a gallon-size Ziploc bag and mailed to Dr. Hancock at the following address:  Dennis Hancock, Ph.D., Forage Extension Specialist, 3111 Miller Plant Sciences Bldg., University of Georgia, Athens, GA  30602. Be sure to include a return address.

If hoary alyssum is identified by Dr. Hancock, please contact Julie Hester of the Georgia Department of Agriculture's Plant Food, Feed and Grain Section at phone at (404) 656-3637 or by e-mail at JHester@agr.state.ga.us.