Many shelter dogs are often mistakenly labeled as a pit bull, according to a new study by the University of Florida. The study, which was recently published in The Veterinary Journal, identified the inaccuracies through DNA testing. “Animal shelter staff and veterinarians are frequently expected to guess the breed of dogs based on appearance alone,” said Julie Levy, DVM, Ph.D., a professor of shelter medicine at the UF College of Veterinary Medicine and lead author of the study. “Unlike many other things people can’t quite define but ‘know when they see it,’ identification of dogs as pit bulls can trigger an array of negative consequences, from the loss of housing, to being seized by animal control, to the taking of the dog’s life. In the high-stakes world of animal shelters, a dog’s life might depend on a potential adopter’s momentary glimpse and assumptions about its suitability as a pet. If the shelter staff has labeled the dog as a pit bull, its chances for adoption automatically go down in many shelters.” The past few decades have brought an increase in ownership restrictions on breeds including pit bulls and dogs that resemble them. The restrictions are based on assumptions that certain breeds are inherently dangerous, that such dogs can be reliably identified and that the restrictions will improve public safety, according to the study. The study focused on how accurately shelter staff identified dogs believed to be pit bulls. ‘Pit bull’ is not a recognized breed, but a term applied to dogs derived from the heritage breeds American Staffordshire terrier or Staffordshire bull terrier, the university noted. The purebred American pit bull terrier is also derived from these breeds and is often included in the loose definition of ‘pit bull.’ As part of the study, the researchers took blood samples from 120 dogs from four shelters and developed DNA profiles for each dog. The DNA results were then compared to what the shelter staff had labeled the dog as. (All staff members—16 in total, including four veterinarians—had at least three years of experience working in a shelter environment.) Dogs with pit bull heritage breed DNA were identified only 33 to 75 percent of the time, depending on which of the staff members was judging them, according to the study. Conversely, dogs lacking any genetic evidence of relevant breeds were labeled as pit bull-type dogs from 0 to 48 percent of the time, the study further noted. “Essentially we found that the marked lack of agreement observed among shelter staff members in categorizing the breeds of shelter dogs illustrates that reliable inclusion or exclusion of dogs as ‘pit bulls’ is not possible, even by experts,” Levy said. “These results raise difficult questions because shelter workers and veterinarians are expected to determine the breeds of dogs in their facilities on a daily basis. Additionally, they are often called on as experts as to whether a dog’s breed will trigger confiscation or regulatory action. The stakes for these dogs and their owners are in many cases very high.” In the end, a dog’s behavior is impossible to predict due to various genetic traits and variants, according to the study. “A dog’s physical appearance cannot tell observers anything about its behavior,” Levy said. “Even dogs of similar appearance and the same breed often have diverse behavioral traits in the same way that human siblings often have very different personalities.” Unless actual pedigrees are available, shelters and veterinary clinics are better off entering “mixed breed” or “unknown” in the dog’s records, according to Levy. As for legal restrictions on dogs based on their appearance, Levy said public safety would be better served by reducing risk factors for dog bites, such as supervising children, recognizing canine body language, avoiding an unfamiliar dog in its territory, neutering dogs and raising puppies to be social companions. The study was funded by Maddie’s Fund and the Merial Veterinary Scholars Program.
