Poisoning and death have been reported for horses consuming bark, leaves, or sprouts. Livestock have also been poisoned by drinking water in which seedpods have soaked. Affected animals often stand with feet spread apart. In severe cases, death can result from cardiac failure. Black walnut is a large tree growing in rich forest soils throughout Ohio.
Leaves are alternate and are pinnately compound with numerous toothed leaflets.
The twigs have a characteristic chambered pith. Black walnut fruits consist of a nut surrounded by a thick husk and do not split open when ripe. The toxic phenolic compound, juglone, is found in the bark, wood, nuts, and roots of black walnut. Horses are primarily affected when exposed to shavings that contain black walnut wood. Affected horses exhibit depression, lethargy, laminitis, distal limb edema, and increased temperature, pulse, respiration rate, abdominal sounds, digital pulse, and hoof temperature.