Most dog parents know that not every healthy human food is good for their pup. Black walnuts can be unhealthy foods for dogs -- they produce a harmful toxin when they become moldy. According to the ASPCA, although the nutty treat may be a no-no for dogs and are bad for horses, they are not toxic to cats -- information to put your mind at ease if your feline starts sniffing around the snack table.
Decomposing Black Walnuts Produce Toxic Mold
A dog can consume black walnut meat if the nuts aren't moldy. But you must inspect them very carefully. Look for signs of rot in the husks, such as a brown or black appearance to see if they are rotten. Your best bet is to keep them away from your dog completely whether you detect rot or not. Regarding the walnut tree in your back yard, keep your canine companion away from the tree when it's shedding the nuts, and remove the nuts from the ground and dispose of them. Moldy nuts produce a toxin that can cause tremors and seizures. Black walnuts are even more highly toxic to horses, even when not rotten The ASPCA reports that equestrian bedding that consists of as little as 5 percent black walnut matter can cause a toxic reaction.