Why do pedigree dogs have higher risk factors for health problems?

If you’re trying to decide what type of dog or puppy is right for you and are reading up on different pedigree dog breeds, you will probably have noticed that virtually all pedigree dog breeds have a hereditary predisposition to certain breed-specific health problems.

Almost all of the pedigree dog breeds that we recognise in the UK – including the best-loved ones like the French bulldog and pug – have certain known health conditions that appear within their gene pools much more frequently than they do in other breeds. Such health conditions may range from very mild to highly acute, and some will have a significant impact on the dog’s quality of life and potential lifespan.

Even within dog breeds that have extensive lists of known hereditary health problems, this doesn’t mean that all or most dogs of the breed will inherit them – and many health testing protocols are in place for common breed-specific health conditions to allow breeders to find out their breeding stock’s risk factors before deciding upon a mating match.

However, the fact that pedigree dog breeds are more likely to have health problems than mixed breed dogs is no accident, and is actually something that we as people have caused and exacerbated to a great degree – which means that it is also something that we should be able to theoretically reduce, and in some cases, eradicate entirely.

If you are wondering why pedigree dogs have higher risk factors for health problems, how this comes about and how the risks can be reduced, this article will outline the main reasons behind the increased risks. Read on to learn more.

Health issues and heredity

The vast majority of the health issues that specific pedigree breeds are known to be at risk for are hereditary in nature, which means that they are passed on from one or both parent dogs to their own young. Gene mutations and genetic anomalies are responsible for most hereditary health issues arising and spreading, and in some cases, we even know the exact genes that cause specific problems, although this is not true for all health conditions.

There are a number of different ways in which a gene fault can be passed on from a parent dog to their offspring, such as by dominant or recessive heredity. Both of these types of heredity are quite complex and come in different types of their own – but recessive genetic health conditions tend to be limited and affect only a small number of dogs, assuming that two dogs that both carry the gene fault aren’t bred with each other.

However, breeding two dogs that both carry the same gene fault increases the chances of a pup inheriting two copies of it, and themselves being affected – as well as their chance of passing it on again if they are bred. Because we select our dogs’ mating matches, the chances of a gene fault being passed on increase as a result of this.

Limited gene pools

Pedigree dog registration is limited to dogs whose parents were themselves both registered pedigrees of the same breed – crossing a dog with another dog from a different breed doesn’t produce a pedigree, and breeding two non-pedigrees of the same breed (or a pedigree and a non pedigree dog) means that their pups will not be eligible for registration.

This makes the size of the gene pools of pedigree dogs smaller, because dogs can only be bred with other registered pedigrees. When the size of the available gene pool is limited in this way, it increases the chances of gene mutations developing, and also of dogs that carry the same mutations being bred from.

This is a risk even for dog breeds with large populations, but is much more acute in breeds for which only a small number of unrelated dogs are available to choose mating matches from. Additionally, dogs that are considered to be excellent examples of their breed (such as high-level show winners) are much in demand for breeding, and stud dogs will often produce a huge number of litters over the course of their breeding careers, making the issue even more acute.

Selective breeding

Selective breeding is the process of choosing a mating match for any given dog, with the intention of producing a litter with all of the best traits of both parents whilst also reducing less desirable factors. Selective breeding is standard practice among pedigree dog breeders, and can improve the quality of dogs of the breed as a whole – but if it is not undertaken carefully and with health and genetic diversity as the priority, it will also increase the risk of spreading genetic health issues.

Conformation defects and deliberate exaggerations

Genetic mutations that lead to hereditary health issues are not the only cause of health defects in pedigree dogs. Deliberate breeding to produce, enhance or exaggerate certain conformation traits can also raise the risk of health problems, by producing a physical appearance that is actually harmful to the dogs that exhibit it.

This is something that we commonly see in brachycephalic dog breeds, which over time, has seen many of the most popular breeds in the UK develop into a modern appearance that is virtually unrecognisable from their historical norms.

Such traits include the very flat faces, huge heads, wide necks and short, heavy bodies of the English bulldog, all of which come with increased risks of health problems.

Limited or absent regulation of breeding and health

Many (but not all) of the hereditary health issues that affect certain pedigree dog breeds can be identified in parent dogs prior to breeding, by means of pre-breeding health testing protocols like DNA screening. This allows breeders to find out whether or not their own dogs are affected by or carriers of any hereditary health issues that will affect their puppies, and allows them to remove unsuitable dogs from their breeding pool.

However, not all breeders undertake all of the recommended tests on their parent stock, and there are actually only a few health issues for which pre-breeding health screening is mandatory in order for a litter to be registered.

Whilst many responsible breeders, animal welfare organisations and breed clubs lobby for health testing as standard, the very limited level of formal oversight and lack of consequences for breeders who don’t health test also contributes to the spread of hereditary health issues.

Buyer demand

Buyer demand for certain breeds of dogs and certain traits within dogs of those breeds drives the dog breeding industry, and for a breeder to make a profit, they have to provide what buyers are looking for.

However, some or the UK’s most popular dog breeds also come with high-level risk factors for conformation or hereditary health issues, which not all prospective puppy buyers realise when they make a purchase – or worse, consider to be a sacrifice worth making to get the cute-looking puppy that they dream of.

Buyer demand for certain breeds and traits has driven and in some cases, directly caused many of the conformation and hereditary health issues found in modern pedigree breeds – and this same consumer power is probably the only effective way to halt the spread of such issues and reverse the trend.

In order to do this, it is important to research in detail any dog breed you might be considering buying, paying particular attention to their health and breed norms – and say no to puppies that have overexaggerated features, untested parents when testing is available, or other traits that increase the risk of health problems in the pup itself.