Watch for Poisonous Weeds in Hay

Most horses cannot differentiate harmful weeds in hay from beneficial long-stemmed forage; this can result in accidental ingestion and possibly a loss in performance or even death.
Share
Favorite
Close

No account yet? Register

ADVERTISEMENT

Most weeds are not palatable and will be avoided by pastured livestock if adequate forage is available. However, in hay, most livestock cannot differentiate weeds from beneficial long-stemmed forage, which can result in accidental ingestion and possibly a loss in performance or even death.

Three weeds commonly found in the upper Midwest that remain toxic when dried in hay are hoary alyssum, wild parsnip, and poison hemlock.

Hoary alyssum is toxic only to horses. It's a perennial weed that is commonly found in pastures and hay fields after areas experience drought. Hoary alyssum is light green to gray in color with white flowers. The seeds are small and oblong and easily seen in baled hay. Horses that ingest hoary alyssum might experience stocking-up or swelling of the limbs, founder, and even death. The toxic dose of hoary alyssum is estimated at 20% (of the plant ingested) in hay, but is known to affect some horses differently. Some horses have a zero tolerance to hoary alyssum.

Wild parsnip is a biennial that is toxic to cattle, horses, and sheep and is infesting ditches and fields in Minnesota. Leaves are course, with saw-toothed edges. Flowers are yellow, and umbrella-shaped. Wild parsnip can contain a toxin called furanocoumarins and can create severe skin irritations. High levels of the toxin have been found in all parts of the plant, including the seeds. The toxic dose of wild parsnip is not known. Signs and effects of toxicity include severe sunburn (photosensitivity). If you suspect wild parsnip toxicity, remove the plant source. Move all affected animals to a shaded area. A topical treatment can be applied to skin lesions. Since wild parsnip is commonly found in ditches, hay harvested from ditches containing wild parsnip should not be fed to livestock

Create a free account with TheHorse.com to view this content.

TheHorse.com is home to thousands of free articles about horse health care. In order to access some of our exclusive free content, you must be signed into TheHorse.com.

Start your free account today!

Already have an account?
and continue reading.

Share

Written by:

Related Articles

Stay on top of the most recent Horse Health news with

FREE weekly newsletters from TheHorse.com

Sponsored Content

Weekly Poll

sponsored by:

Where do you primarily feed your horse?
276 votes · 276 answers

Readers’ Most Popular

Sign In

Don’t have an account? Register for a FREE account here.

Need to update your account?

You need to be logged in to fill out this form

Create a free account with TheHorse.com!