Black walnut trees (Juglans nigra) are commonly found in parks and forests throughout eastern North America.1 This hardy heartwood tree is used in landscaping and is commonly grown for wood or the edible nuts.1 The trees and their nuts are often found in private yards and may be available to dogs when nuts fall, branches break off, or trees are cut down.
Serious clinical signs of toxicosis have been described in a clinical report of a dog that ingested walnuts that were moldy and contaminated with tremorgenic mycotoxins.2 These mycotoxins can cause muscle tremors, vomiting, hyperthermia, seizures, and tachycardia in dogs.3 Black walnut shavings used as bedding have been associated with laminitis in horses,4 but to the authors’ knowledge, no illnesses attributed to exposure to black walnut wood or wood shavings have been reported in other species, and the literature contains no reports of clinical signs in dogs that have ingested black walnut wood or nuts.
Veterinary staff members at the ASPCA APCC, a 24-hour consultation service that receives calls from throughout the United States and Canada concerning accidental or environmental animal poisonings from animal owners and veterinarians, observed that dogs reported to ingest black walnut wood seemed to have different clinical signs of toxicosis than did dogs reported to ingest black walnuts or black walnut hulls. The purpose of the study reported here was to identify clinical signs associated with oral exposure to black walnut wood, nuts, or nut hulls in dogs and to compare clinical syndromes between dogs that ingested wood and those that ingested black walnuts or their hulls. Our hypothesis was that there would be a difference in the types of signs seen following ingestion of these black walnut tree components.
The authors thank Dr. Margaret Slater for assistance with statistical analysis and Dr. Safdar Khan for advice regarding the manuscript.
No outside funding was received in connection with this study. The authors declare that there were no conflicts of interest.
Animal Poison Control Center
American Society for the Prevention of Cruelty to Animals
Stata Statistical Software, Release 11, Statacorp LP, College Station, Tex.
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