The shortened snouts, stubby legs and protruding underbite give English bulldogs their signature look. However these features along with an abundance of health problems are also tell-tale signs that their genetic line has nearly reached an end.
The highly selective breeding involved in crafting the bulldog's extreme features has also created significant health issues and erased the genetic diversity needed to solve them. The diversity needed to improve the breed — as in, to correct the myriad health problems from hip dysplasia to cherry eye, from skin infections to respiratory problems — just isn't there.
The study, "A genetic assessment of the English bulldog," notes:
The results confirm that the breed has lost considerable genetic diversity through such things as small founder population and artificial genetic bottlenecks resulting from highly focused selection for specific desired physical traits... The loss of genetic diversity and extreme changes in various regions of the genome will make it very difficult to improve breed health from within the existing gene pool. Loss of present genetic diversity is further threatened by rapid integration of new coat color mutations, increased wrinkling of the coat, and attempts to create a more compact body type.
Basically, we've loved the English bulldog to death, and we've sacrificed the dog's longevity and health for funky features.
Any hope for improving the health of English bulldogs depends on introducing some fresh genes into the pool, and that most likely means bringing in the genes of other breeds.
According to Gizmodo, "In an effort to address this problem, some Swiss breeders have started to mix English Bulldogs with the Olde English Bulldogge — a recently created American dog breed — to create a Continental Bulldog. This 'outcrossing' of breeds could improve the health of bulldogs, though [lead author of the study Niels] Pederson is skeptical."
Sadly, as the study shows, we're likely beyond the point of no return when it comes to improving the health of English bulldogs as a pure breed.