The human race has loved purebred dogs since antiquity. More than 2,000 years ago, breeders mated certain dogs to one another to produce desirable traits, resulting in some of the world’s oldest but still recognizable breeds. The Chinese Shar-Pei, for instance, was in existence in the 200s BCE, while the Saluki’s likeness has been found in Egyptian tombs and first originated in the Fertile Crescent more than 4,000 years ago.
Point being? We love purebred dogs, whether it’s for their swiftness, resourcefulness, intelligence or plain old beauty. Today, the industry is a huge one, supplying people with gorgeous, papered pups for the purposes of show training, breeding or plain old home enjoyment.
The not-so-happy news: Purebred dogs carry a significantly higher incidence of genetic defects than “mutts” or non-purebreds. That’s because in purebreds, genes tend to concentrate, which brings out unwelcome traits as well as desirable ones. Moreover, several toxins can influence gene expression as well, resulting in defects that studies show are closely associated with environmental toxins.
One such trait is the cleft palate. According to anecdotal evidence, it is becoming more common in breeds of all kinds. Not only does this cost breeders money, it’s a shame for breeding mothers to go through so much and experience less-than-optimal results (even if they don’t know it).
It’s time to address the issue of cleft palates in purebred puppies … and more importantly, to do something about it.
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According to Pet Health News, “Cleft lip (often referred to incorrectly as a ‘hair lip’ or more appropriately as palatoschisis or congenital oronasal fistula) and cleft palate are birth defects that occur when a puppy’s lip or mouth do not form properly during pregnancy.”
There two main forms a cleft palate can take. Primary cleft palate is when the lips do not come together, whereas secondary cleft palates are when the roof of the mouth isn’t sealed, with leaves a hole between the nasal passages and the mouth. Sometimes this makes dogs incompatible with life.
Dogs with cleft palates can survive, though, and often do. However, the unsightliness of external cleft palates often makes them unsuitable for shows, discourages breeders from using them (as it should, discussed below), and in many cases makes life less comfortable for the dog.
While primary cleft palates are obvious, because they cause disfiguration in the external mouth and nose, secondary cleft palates may be harder to catch. This is especially true when the cleft, or opening, is small. You can spot secondary cleft palates if the pup:
If you notice any of these signs, it’s worth checking into the presence of a cleft palate. Even experienced breeders can miss them, so look carefully or take the pup to a vet if necessary.
Scientists aren’t sure why exactly cleft palates occur, though they do know that genetics plays a big part. Purebred animals tend to exhibit recessive tendencies that would be bred out if they were mixed with other breeds. When two purebred animals that have the same gene breed, however, the combination of genetics can make the trait manifest.
Recently, researchers have identified the mutations that cause them in the Nova Scotia Duck Tolling Retriever. Identifying this gene has allowed breeders to avoid breeding dogs that carry it. The more research is done into specific breeds, the more success dog breeders will have in avoiding them.
Unfortunately, genetics is not the only indicator. Others include:
Because of these multiple factors, avoiding cleft palates means taking a number of different approaches.
Many breeders are frustrated by their inability to control for these traits through simple breeding, though, so let’s take a look first at why that’s not working today.
Many breeders today are frustrated by cleft palates, both because they can’t find a reason for their existence and because they can’t figure out how to avoid it. Sadly, that’s because cleft palates are not a straightforward recessive trait.
At this point, a quick science lesson on dominant and recessive traits will help. Dominant genes will take precedence over recessive genes. That means, all things being equal, when a dominant and recessive gene go head to head, the dominant gene will manifest. For example, brown eyes win over blue eyes in both people and dogs. In order for blue eyes to express, the animal must carry only blue-eyed genes, otherwise brown would “win.” However, if a blue-eyed animal mates with another blue-eyed animal, the offspring will have blue eyes.
With many traits, you can control well with breeding. For instance, if you breed two chocolate labs, you will get chocolate puppies. If you breed yellow labs, you will get yellow puppies. That’s because both chocolate and yellow are recessive traits, so if the parents to be those colors, the dog can’t carry the dominant gene for black fur.
Similarly, if you mate two dogs of the same pure breed – for instance, Cane Corsos – you will get Cane Corso puppies. So at the breed level, purebreds will breed true. And as stated above, there are some recessive traits that are straightforward, such as the example of lab coloration.
Unfortunately, this doesn’t hold true for a lot of traits. Cleft palates, for instance, are an extremely complex syndrome influenced by a lot of different genetic factors rather than one straight recessive trait. It’s true that if you breed two dogs with cleft palates, you would likely get cleft palates. However, that doesn’t mean the opposite is true. If you breed two dogs without cleft palates, you may very well still get them.
The above might be a bit of a deep dive, but it’s necessary for understanding why established breeding practices aren’t fixing this problem. This is what drives breeders mad. For years, they’ve been able to use simple matching or avoidance of traits to control what traits express … and now they must find a different way. So the question becomes, if you can’t control for cleft palates in a straightforward fashion, then how?
It is important to acknowledge that because there is such a strong genetic component to cleft palate, it is possible to reduce the incidence simply by ending a family line that has produced multiple cases. However, as discussed, that’s often not enough, which is when we turn to external rather than internal factors.
We have long known that environmental factors influence gene expression, or how those genes manifest in the body. For instance, temperature influences whether Himalayan rabbits have black paws and facial traits, or are pure white everywhere.
Other genetic influences aren’t so harmless, though. Thalidomide in human babies is a famous example. Marketed by drug companies to combat morning sickness, this drug is safe for adults. However, it’s extremely detrimental to developing fetuses, who came out with missing or severely truncated limbs. The takeaway: some chemicals, even ones that are safe for adult mammals, may be harmful to fetuses in utero.
New studies indicate that cleft palates arise due to three relatively common contaminants: nitrates, atrazine, and arsenic. These are primarily agricultural compounds and have been found to act as teratogens (substances that cause disruption to developing embryos). These include “neural tube defects, oral clefts, and limb deficiencies.” This study specifically studied humans, but as many mammal results may be generalized to other mammals (mice to humans, for instance), it is safe to assume that this is a danger to developing pups as well.
Another study finds that “Evidence from animal studies suggests that maternal inorganic arsenic may lead to the development of orofacial clefts (OFC)s in offspring.” This, combined with the fact that “Arsenic is widely distributed in the environment in both inorganic and organic forms,” indicates “the need for a comprehensive examination of major sources of arsenic exposure and OFCs.”
Unfortunately, contaminated drinking water is not an isolated problem. New information from the Oregon Environmental Council indicates that thousands of Oregonians may drink water containing agents that can cause birth defects. It goes without saying that breeding dogs are drinking that water as well, and the results for their puppies could be just as dire.
The answer? Always test private wells for contaminants, which you can do by contacting the applicable state agency or ordering a test online. This will give you the information you need to make safer drinking water choices, both for the humans and dogs in your life.
Because research on dogs is so much more limited than on humans, is unclear on what exactly causes cleft palates. It is clear that environmental factors, disease and toxicity may cause them to manifest, though. Therefore, the best thing a breeder can do is to ensure the healthiest possible environment and nutrition. That means:
Doing the above, along with discontinuing the breeding of dogs that have produced a substantial amount of cleft palate puppies, can help reduce the incidence significantly.
It’s important to note that some breeds are likelier to manifest cleft palate than others. While cleft palate occurs in all dogs with an incidence rate of up to 25 percent, the odds are 30 percent higher than that in brachycephalic dogs. The name, which comes from the Latin for “short-headed,” refers to any dog with a pushed-in snout and flat face, as opposed to the typical long snouts that wild dogs and wolves possess.
This may lead you to conclude that you should avoid brachycephalic dogs, both as a breeder or an owner. That’s not true, however. While brachycephalic animals are slightly less suited to hot weather because of airways that function a bit less efficiently than other dogs, they don’t tend to have greater health problems than other purebreds (think labs and hip dysplasia, for instance). Instead of avoiding such breeds, it’s important to simply look for a reputable breeder.
Whether you are choosing a puppy to breed yourself or simply to love in your home, it’s critical you take steps to support breeders that work hard to raise and produce dogs compassionately and ethically. Sadly, puppies with birth defects are a real problem today. When the birth defect is truly incompatible with life – as it most often is with cleft palate – the puppy will likely get a humane death. However, what if the puppy has a defect that makes it special needs, but can still live?
In some cases, timely intervention can fix the problem well enough that puppies can transition to solid foods at normal times and live healthy lives, even if they are less valuable to breeders. Other times, breeders have a hard time selling or even giving these dogs away. That raises the unpleasant question of what happens with those dogs, a question everyone would rather not have to ask. Some go to shelters, while others live with breeders as long as their defect allows and still others live with them until they can go to good homes later on.
The best solution to this problem is to avoid cleft palates in the first place. That means working only with knowledgeable breeders who use the latest research to avoid birth defects. If you’d like to learn more about professional breeders who produce good dogs and follow good ethical practices, we’d be happy to tell you more today. All you have to do is get in touch.