Genetic Assessment Study Prompts Call for Revised Bulldog Breed Standards

September 14, 2016
Sarah Handzel, BSN, RN

A study designed to determine if there was enough genetic variation in English bulldogs to correct genotypic and phentoypic abnormalities found the breed has lost most, if not all, of its genetic diversity.

The British Veterinary Association (BVA) is calling for the revision of breed standards regarding English bulldogs after a study suggested that the breed has lost much, if not most, of its genetic diversity. The calls for revision come amid concerns that the lack of diversity in the breed might not be sufficient to address specific health concerns through reverse selection.

The study explored the genetic diversity of 102 registered English bulldogs, male and female, that are used for breeding purposes. Researchers wanted to see if the bulldogs retained enough variation within the breed genome to correct both genotypic and phenotypic abnormalities that have been associated with health issues. The researchers were also interested in whether there was enough diversity to help eliminate certain damaging recessive mutations, and whether any further phenotypic changes could be made to the breed’s appearance, both in body structure and coat.

It was determined that, of the bulldogs sampled for the study, there existed a very low genetic diversity that’s resulted from small founder populations and genetic bottlenecks created by human breeders. While researchers found there is still genotypic and phenotypic diversity within the breed, it’s not known whether the diversity is enough to use reverse selection in order to improve the breed’s health. It’s also not known whether this small amount of variation could be used to select against damaging recessive traits, or if it’s sufficient to allow for further selection of body structure and coat traits.

As Sean Wensley, President of the BVA, announced: “revision of breed standards, to include evidence-based limits on physical features such as muzzle shortness, and full consideration of other approaches such as outcrossing, are now needed to ensure high risk breeds, such as the English bulldog, do not continue to suffer unnecessarily.”

Most veterinarians are already quite familiar with the problems associated with the English bulldog breed. Since the breed is brachycephalic, they usually have lifelong breathing difficulties, in addition to other common problems like chondrodysplasia; teeth, skin, heart, eye, and immune issues; and high rates of congenital diseases.

Veterinarians are in a unique position to offer advice to owners and prospective owners of the typical health issues of the breed. It’s part of the duty of veterinarians to prioritize and work toward the best interest of the animals they treat, and part of that duty can be performed by supporting initiatives addressing specific health and wellness issues affecting entire breeds, not just individual animals.