No, black walnut shavings are not recommended. Black walnut (Juglans nigra) wood shavings can elicit clinical signs of laminitis or founder within 8 to 24 hours of coming in contact with the bedding. Consumption of the bedding may also cause laminitis signs as well as colic. Affected horses may be unable to move because of soreness in their feet. They may also be depressed and have difficulty breathing. Laminitis often occurs in the front feet but can affect the hind feet as well. Permanent damage to the hoof laminae may result, and the attachment of the coffin bone to the hoof wall can break down, resulting in the whole weight of the horse bearing down on the coffin bone. If signs of laminitis are present, it is recommended to call a veterinarian immediately.
The toxin causing equine laminitis has not been clearly identified. There is no evidence that black walnut wood shavings affect other livestock species such as sheep, although dogs should not be allowed to consume black walnut seed hulls because they can cause severe gastroenteritis.
The following Web site has a fact sheet that may be helpful.