The Cane Corso was found at School No. 9 in Woodbridge on Tuesday.
Township spokesman John Hagerty tells The Star-Ledger of Newark the dog was tied to the school's backdoor with a leash. Hagerty says the ears were "cut flush to the head."
The male dog is black with a white star in its chest.
The dog has been treated by a veterinarian and taken to the Woodbridge Animal Shelter.
Information from: The (Newark, N.J.) Star-Ledger, http://www.nj.com