Cross-breeding the English bulldog with another breed is the best way to ensure its survival, scientists have argued.
A genetic study suggested that the bulldog has become so inbred, due to selective breeding, it cannot be returned to health without an infusion of new bloodlines.
The study, which appears in Canine Genetics and Epidemiology explained that the Olde English Bulldogge, a related breed from America, is a viable option for breeders.
Study co-author Niels Pedersen, from the University of California, Davis, told BBC News: “We tried not to be judgemental in our paper. We just said there’s a problem here, and if you are going to decide to do something about it, this is what you’ve got to work with.
“If you want to re-build the breed, these are the building blocks you have, but they’re very few. So if you’re using the same old bricks, you’re not going to be able to build a new house.”
Prof Pedersen told BBC News: “Some small breeds with a small number of registered dogs have attempted this. But it’s not common for breeders to admit that they’ve reached a point with health problems where they have to do something drastic such as reverse breeding.
“The fastest way to get genetic diversity is to outcross to a breed that looks similar but is genetically distinct… Trying to manipulate diversity from within a breed if it doesn’t have much anyway is really very difficult. If all your dogs are highly related to one another, which ones are you going to pick?”
“There are some English Bulldogs that can breed normally and give birth normally. There are some that are more mobile than others, there are some that can breathe better than others, some that don’t have the skin allergies and auto-immune disorders,” said Prof Pedersen.
“But they’re relatively few and it’s hard to find one individual that contains all of those traits. You may have one English Bulldog that does not have the extreme changes in the head so that they breathe easier, but they may have lots of skeletal problems that lead to extreme arthritis.”
Some have argued that if the breed’s standards were altered then it would no longer be an English Bulldog.