Re: Black Walnut

[Arabryder@aol.com]

Here's the entry in the "Horse Owner's Field Guide to Toxic Plants" regarding
Black Walnut:

Similar Species:  Eastern Black Walnut; Texas Black Walnut; Arizona Black
Walnut

Description:  Depending on the variety, the black walnut tree may grow up to
125 feet, with a grayish brown, scaly bark and pinnately compound alternate
leaves.  It produces spiked flowers in spring or early summer and small oily
nuts, which are often harvested in fall.

The toxic principle juglone, which is a growth inhibitor, is carried in the
roots of the tree to other plants surrounding it, inhibiting their growth.
Experimentally, juglone has not been shown to cause toxicosis in horses.
Furthermore, toxicity is not consistent in black walnut trees.

Geographic Distribution:  Scattered throughout eastern and midwestern United
States, south to George, Texas and Arizona

Signs of Poisoning:  Horses are affected when the sawdust or shavings from the
tree are used bedding.  They show an allergic reaction when standing in the
shavings and do not have to ingest them to become sick.  As little as 5-20
percent black walnut shavings can cause symptoms of laminitis, swelling in the
legs, depression, unwillingness to move, and, in some horses, respiratory
difficulties within 12 hours.

What to Do:  Remove the horse immediately from the walnut shavings.  Wash the
horse's legs with mild detergent, and call your veterinarian to treat the
laminitis.