UC Davies has recently published a paper in the peer-reviewed journal Canine Genetics and Epidemiology examining the genetic diversity among 102 registered English Bulldogs, all used for breeding. The authors’ objective was to assess whether the breed retains enough genetic diversity to correct the abnormalities associated with poor health which have a genetic basis and which can be seen in the outward appearance of many dogs.
Predictably, some in the bulldog fraternity have attempted to discredit the paper while other continue to stick their fingers in their ears and their heads in the sand. The health problems of this breed, as the authors note, are well documented and include:
Severe conformational changes necessitating a high rate of artificial insemination and Caesarean sections
Small litter sizes (inbreeding depression)
Extremely high levels of congenital disease and associated puppy mortality including flat chests with splayed legs, anasarca and cleft palate
Poor lifespan ranging from 3.2 to 11.3 years with a median of 8.4 years as dogs requiring extensive veterinary care at a young age rarely live beyond 5–6 years of age.
The bulldog suffers its own particular problems due to brachycephaly combined with a tongue that is excessively large at the base, a large palate that is easily obstructed by the base of the tongue, a lower jaw that is pushed forward, frequently stenotic nares and a hypoplastic trachea. Consequently, they suffer from loud panting during exercise, stridor and slobbering during rest, sleep apnoea, hypercapnia and hypochloremia/hypomagnesemia, exercise intolerance, cyanosis and collapse and choking fits manifested by gagging, retching, vomiting, aerophagia, flatulence and aspiration pneumonia. The breathing difficulties of English bulldogs also make them very sensitive to overheating and heat stroke.
Chondrodysplasia, a heritable skeletal disorder, predisposes English bulldogs to hip and elbow dysplasia, luxating patella and shoulders, intervertebral disk disease, cruciate ligament rupture, hemivertebra, torsional pelvic deformity and, as mentioned, difficulty in achieving normal copulation and parturition. Prognathism predisposes to dental disease, while excessive folding of the skin, especially on the face, is associated with skin fold dermatitis, muzzle acne, folliculitis, furunculosis and eye conditions such as entropion, ectropion and eversion of the third eyelid. The cork-screw tail can result in tail fold dermatitis. Inbreeding has also produced cataracts, heart valve defects including pulmonic stenosis, hydrocephalus, cysteine urolithiasis and hiatal hernias, immunologic disorders including a propensity for severe demodectic mange due to immunodeficiency, allergies associated with atopic dermatitis and ear infections and autoimmune diseases such as hypothyroidism. The common range of cancers include glioblastoma, mast cell sarcoma and lymphoma.
Doesn’t sound like a very healthy breed does it?
Many owners who accept these defects as “normal” pay huge amounts for treatments as their dogs stagger through their shortened lives but many dogs also end up in rescue or are euthanised due to the prohibitive cost of treatment.
All may not be lost as there are a few bulldogs out there that can breathe and move freely, reproduce naturally and that are free from skin and eye problems, allergies and other immunologic disorders.
The papers authors are therefore calling the bluff of bulldog owners outraged by their paper. They have issued a global challenge to bulldog breeders and owners to provide proof that their dog is a purebred (registered), healthy English bulldog. Owners are requested to e-mail the authors with supporting evidence. If the dog is deemed to meet the criteria as defined by the authors, the Veterinary Genetics Laboratory at UC Davies will provide a free DNA collection kit from which a genetic profile of the dog can be compared with the information provided in the genetic assessment paper and added to the genetic profile database for the English bulldog. The aim is to identify a genetic profile that is conducive to greater health and it may yet save the breed from imploding.
Pedersen NC et al (2016) A genetic assessment of the English bulldog, Canine Genetics and Epidemiology, V3(6) DOI: 10.1186/s40575-016-0036-y [accessed online at https://www.vgl.ucdavis.edu/services/dog/GeneticDiversityInEnglishBulldogs.php]
Thanks to Pedigree Dogs Exposed for this information.