Your Purebred Will Likely Live Two Years Less Than Their Grandparents Did. Here's Why.
Average Coefficient of Inbreeding by Population
Where the average purebred dog sits on the genetic relatedness scale
227 BREEDS STUDIED
COMPARISON GROUP
The average purebred dog has a coefficient of inbreeding equivalent to the offspring of a brother-sister mating. Mixed-breed dogs in the same study had inbreeding levels nearly seven times lower. Bannasch et al. 2021, Canine Medicine and Genetics
The Cost of the Closed Studbook System
Population-level median survival, drawn from peer-reviewed veterinary epidemiology
Population-level median survival aggregated from McMillan 2024 (584,734 UK dogs), Klopfenstein 2016, and primary care veterinary databases. The breeds with the most documented closed-studbook genetic load consistently show the shortest median lifespans. McMillan et al. 2024, Scientific Reports; Klopfenstein et al. 2016, BMC Veterinary Research
Heterosis Retained by Breeding System
Why first-generation crosses capture maximum hybrid vigor
Expected heterosis retention is a mathematical function of population structure, not species. The principle holds across cattle, swine, poultry, and canines. Multigenerational hybrid breeding within a closed gene pool predictably loses the fitness benefits captured in the first-generation cross. Falconer and Mackay 1996; Gregory and Cundiff, USDA Meat Animal Research Center
How a Closed Studbook Loses Genetic Diversity
Each generation drawn from a smaller and smaller share of the original gene pool
Each colored dot represents a distinct genetic line. In a closed studbook, every generation is drawn from the previous one. Without new founders, alleles can only be lost. Genetic drift, popular sire effect, and selection collapse the population to a narrow share of the original genetic diversity, concentrating the homozygosity that produces recessive disease expression. Lewis, Abhayaratne, and Blott 2015, Canine Genetics and Epidemiology
Three Alternatives Worth Considering
Preserving the temperament of the breed while broadening the genetic foundation
| Bernese Mountain Dog |
Australian Mountain Dog |
Unfurnished AMD |
Bernedoodle (F1) |
|
|---|---|---|---|---|
| Median Lifespan | 6–8 yrsDocumented | Expected longerHybrid vigor principles | Expected longerHybrid vigor principles | Expected longerHybrid vigor principles |
| Average COI | 27–39%Bannasch 2021 | 0–4%Stokeshire data | 0–4%Stokeshire data | 0–4%Stokeshire data |
| Cancer Mortality | 55–58%Erich 2013 | Insufficient long-term data |
Insufficient long-term data |
Insufficient long-term data |
| Adult Size | 80–115 lb | 50–75 lb | 50–75 lb | 50–80 lb |
| Coat Shedding | Heavy year-round |
Low to moderate |
Moderate to heavy |
Low to none |
| Temperament | Gentle, calm, deeply bonded |
Gentle, calm, working intelligence |
Gentle, calm, working intelligence |
Gentle, intelligent, family-oriented |
Each alternative represents an intentional cross designed to preserve the best of the Bernese temperament while drawing genetic diversity from compatible parent breeds with substantially different genetic backgrounds. The choice is not whether to love the Bernese. The choice is whether to also have a longer life with the dog you love. Stokeshire program data; comparative breed data from cited peer-reviewed sources
““The average purebred dog alive today is the genetic equivalent of the offspring of a brother-sister mating.””
A position paper from Stokeshire Designer Doodles
By James Stokes | Founder, Stokeshire Designer Doodles | Medford, Wisconsin
In 2021, geneticist Danika Bannasch and her colleagues at the University of California Davis published a study in Canine Medicine and Genetics analyzing the genetic diversity of 227 dog breeds. Their findings, drawn from genomic data rather than pedigree records, established something that should have ended the conversation about purebred dog health years ago.
The average purebred dog in the study had a coefficient of inbreeding of 24.9 percent.
To translate that number: the average purebred dog alive today is the genetic equivalent of the offspring of a brother-sister mating.
This is not a marketing claim from a doodle breeder. It is peer-reviewed research, published in a respected veterinary genetics journal, drawn from genomic analysis of hundreds of breeds and tens of thousands of individual dogs. The mixed-breed comparison group in the same study had an average coefficient of inbreeding of 3.7 percent — roughly seven times lower than the purebred average.
For most prospective owners, this number means nothing. They have never been told it. They have never been asked to consider it when making a purchase decision. The veterinary establishment, the kennel clubs, and the breed clubs have collectively allowed an entire culture of dog ownership to develop around an unstated premise: that "purebred" means "carefully bred," and that "carefully bred" means "healthy."
The peer-reviewed literature documents that this premise is, for many popular breeds, false.
What follows is a synthesis of the research, the mechanism that produced this situation, and the case for an alternative model. It is also a description of what we are building at Stokeshire and why we believe it represents a path forward.
Section 1: The Lifespan Pattern
The Bernese Mountain Dog provides the clearest single-breed illustration of where closed studbook genetics has led.
A 2016 study published in BMC Veterinary Research by Klopfenstein and colleagues analyzed Bernese Mountain Dogs in Switzerland and reported a median life expectancy of 8.4 years. Erich and colleagues, in a 2013 study, found that at least 55.1 percent of Bernese Mountain Dog deaths in their cohort were associated with malignant tumors. Histiocytic sarcoma alone, a cancer that is rare in most breeds, has been documented in subsequent peer-reviewed literature as occurring in Bernese Mountain Dogs at rates as high as 225 times the rate in other breeds.
For owners who have loved a Bernese Mountain Dog through their too-short life, none of this is surprising. The grief of losing these dogs at six or seven years is the central emotional fact of the breed for most owners.
The Bernese is not an isolated case. The pattern repeats across multiple popular breeds:
The Cavalier King Charles Spaniel, recreated in the 1920s from a small founding population, now carries myxomatous mitral valve disease at a population-wide level so severe that nearly every dog in the breed shows signs of heart disease by age ten. Chiari-like malformation and syringomyelia, conditions caused by a brain that is too large for the skull, affect an estimated 70 to 90 percent of the breed.
The English Bulldog, in the 2024 McMillan study of more than 580,000 UK dogs, showed a median lifespan of 9.8 years. The Pug showed 11.6 years. Both breeds suffer from brachycephalic obstructive airway syndrome at population-wide rates, a direct consequence of selecting for the flat-faced morphology that defines them.
The Doberman Pinscher carries dilated cardiomyopathy at population-wide rates that have made the disease the leading cause of death for the breed.
The Boxer carries cancer mortality rates approaching 44 percent.
The Great Dane lives, on average, 7 to 10 years.
The Golden Retriever, one of the most popular breeds in the world, dies of cancer in 60 to 65 percent of cases.
These numbers come from peer-reviewed veterinary epidemiology. They are not opinions. They are not anecdotes. They are population-level mortality data drawn from primary care veterinary databases, kennel club registries, and longitudinal cohort studies covering hundreds of thousands of dogs.
The pattern is structural. The mechanism is the same across breeds.
Section 2: The Mechanism — Closed Studbooks and the Mathematics of Genetic Decline
Modern purebred dog breeding operates under a system called the closed studbook, established in the late nineteenth century by the major kennel clubs. The rule is simple: a dog can only be registered as a member of a breed if both of its parents are already registered as members of that same breed.
This system was created with reasonable intentions. It standardized breed identity, allowed for predictable physical characteristics, and gave breeders a framework for tracking lineage. What it did not account for was the mathematical certainty that a closed population, over generations, will lose genetic diversity.
In a closed population, every generation is drawn from the genetic material of the previous generation. Without the introduction of new founders, alleles can only be lost through three mechanisms: genetic drift, selection, and the disproportionate breeding contribution of a small number of individuals. They cannot be replenished except through mutation, which operates on timescales irrelevant to the dog generation.
Lewis and colleagues, in a 2015 analysis of more than 11 million UK Kennel Club registrations published in Canine Genetics and Epidemiology, concluded that inbreeding is mathematically inevitable in closed populations with finite ancestors and selection. The only question is the rate at which it accumulates.
The rate has been substantial. Across most popular breeds, generations of closed-studbook breeding have produced the genomic situation Bannasch documented in 2021: average inbreeding coefficients equivalent to full-sibling matings.
A second mechanism has accelerated this process: the popular sire effect. When a single male dog produces a disproportionate share of a generation's offspring — typically because of show success, a desirable physical trait, or fashionable appearance — that one dog's genetics are amplified across the breed. In Bernese Mountain Dogs, genealogical studies have documented that fewer than one percent of sires have produced more than half of subsequent generations. Every recessive disease allele that one dog carries is then disseminated across the breed in a single generation.
The mathematical consequence is the concentration of homozygosity at disease-relevant loci. Most genetic diseases in dogs are recessive, meaning a dog must inherit two copies of the disease allele to express the condition. When inbreeding raises the probability that two copies will meet in the same offspring, conditions that were once rare become common. Conditions that were once breed-specific become breed-defining.
This is not a hypothesis. It is the documented genetic history of nearly every popular purebred breed.
“There is no biological reason that the principle that governs cattle, swine, poultry, plants, and laboratory animals would exempt canines.”
Section 3: The Hybrid Vigor Evidence
The genetic principle that crossing two unrelated populations produces offspring with measurable health and fitness advantages has been understood since the early twentieth century. It is not controversial science. It is foundational quantitative genetics, established by Sewall Wright and codified in the standard textbook Introduction to Quantitative Genetics by Falconer and Mackay.
The mechanism is straightforward. When two genetically distinct parental populations are crossed, the offspring inherit one allele from each parent at every gene location. Because the parents differ in allele frequencies — they have evolved within separate populations and accumulated different recessive disease alleles — the offspring are highly likely to inherit a functional allele from one parent that masks any deleterious allele from the other.
This effect, called heterosis, is mathematically maximized in the first-generation cross between two distinct populations. The offspring achieve nearly complete heterozygosity at loci where the parental populations differ. Recessive disease alleles that exist in either parent population are masked rather than expressed. Fitness, measured across longevity, fertility, immune function, and metabolic health, is improved.
The evidence base for this is overwhelming, but most of it does not come from canine research. It comes from agricultural genetics, where the dairy and beef cattle industries have spent decades running controlled crossbreeding studies on millions of animals.
In the dairy industry, the University of Minnesota research program led by Brad Heins and Les Hansen has documented across multiple peer-reviewed studies that first-generation Jersey-Holstein crossbred cows show measurable advantages over purebred Holsteins. In one published comparison, the F1 crosses showed 23 fewer days open between calvings, a 16 percentage point higher conception rate by 150 days, lower calving difficulty scores, and better body condition — all statistically significant at P less than 0.05. The pure Holsteins produced slightly more milk volume, but the F1 crosses captured fitness advantages that the closed Holstein population had lost through generations of selection for production traits.
The dairy industry has institutionalized these findings. The standard recommendation from major dairy science extension programs is now three-breed rotational crossbreeding, which maintains heterosis at approximately 86 percent of F1 levels indefinitely. This is the system that the largest commercial dairy operations in the United States and Europe now use.
In the beef industry, the USDA Meat Animal Research Center, under researchers Keith Gregory and Larry Cundiff, has documented across multiple studies of composite breed populations that stabilized multigenerational hybrids retain only a fraction of the heterosis seen in F1 terminal crosses. A two-breed composite retains 50 percent. A four-breed composite retains 75 percent. An eight-breed composite retains 87.5 percent. None reach the 100 percent heterosis of the F1.
This is the agricultural literature speaking. Decades of controlled studies, millions of animals, and unambiguous findings: F1 crosses between genetically distant parental populations capture maximum hybrid vigor. The benefits decline predictably as populations become stabilized through inter-se mating.
The canine literature is more limited, in part because purebred dog breeding has not historically been studied with the same scientific rigor as commercial agriculture. But the genetic mechanism does not change between species. There is no biological reason that the principle that governs cattle, swine, poultry, plants, and laboratory animals would exempt canines.
A single canine study, published by Bellumori and colleagues in the Journal of the American Veterinary Medical Association in 2013, analyzed 27,254 dogs across 24 inherited disorders. Purebred dogs were significantly more likely to have 10 of the 24 disorders, including dilated cardiomyopathy, elbow dysplasia, and early-onset cataracts. Mixed-breed dogs were significantly more likely to have one disorder, ruptured cranial cruciate ligament. For 13 disorders, prevalence did not differ significantly between groups.
This is the picture: hybrid vigor is real, it is measurable, and it is mechanistic. It is not a marketing claim made by breeders trying to sell expensive crossbred dogs. It is the consequence of a mathematical principle that operates across all sexually reproducing species.
Section 4: The Numbers Inside Our Program
What does this look like when applied to a working canine breeding program?
A coefficient of inbreeding measures the probability that two alleles at a given gene location are identical because they were both inherited from a common ancestor. The number is reported as a percentage. A COI of 0 percent means the two alleles came from genetically unrelated sources. A COI of 25 percent is the equivalent of a full-sibling mating. A COI of 50 percent is the equivalent of a parent-offspring mating.
Bannasch's 2021 study reported the average across 227 purebred breeds at 24.9 percent.
In our active Bernedoodle program, COI on individual breeding dogs ranges from 0 percent to 8 percent, with most active dogs in the 0 to 4 percent range. The Bernese Mountain Dog parents we use for first-generation Bernedoodle crosses carry COI values typical of the breed — in the high 20s to high 30s percent range — but their F1 crossbred offspring consistently show COI values at or near 0 percent.
This is the agricultural F1 heterosis principle, applied to canines. A purebred parent with a COI of 27 percent, bred to a Standard Poodle parent with a COI of 3 percent from a substantially unrelated genetic background, produces F1 Bernedoodle offspring with COI of 0 percent. In one generation, the closed-studbook genetic load that took 150 years to accumulate is masked by the introduction of unrelated genetic material from a different breed.
This is the structural fact that distinguishes a thoughtfully managed F1 hybrid program from a closed-studbook purebred program. The math is identical to the dairy industry's findings. The mechanism is identical. The expected outcome — improved fitness, longevity, and disease resistance — is identical.
Stokeshire's active program prioritizes F1 crosses between genetically diverse, health-tested parent breeds, with COI tracking on every pairing. We do not breed within a closed Stokeshire-only gene pool. We actively introduce new breeding stock from outside our program to prevent the population drift that affects both purebred breeding and stabilized multigenerational hybrid breeding.
This is the model. It is operationally expensive. It requires tracking pedigrees, managing COI calculations, maintaining relationships with other breeders to source unrelated breeding stock, and accepting that you cannot simply breed your own offspring back into your own program at scale. But it is the model the agricultural literature, across decades and millions of animals, has identified as producing the fitness benefits that hybrid breeding promises.
Section 5: If You Love the Bernese Mountain Dog, Read This
For families considering a Bernese Mountain Dog, the data presented above is not an attack on the breed. It is information that Bernese owners deserve to have when making one of the most consequential purchase decisions of their lives.
The Bernese is, by every account, an extraordinary dog. Gentle, deeply bonded to family, calm in temperament, dignified in bearing. The cultural image of the Bernese as a family dog is not marketing. It reflects a real and beloved breed that has earned its reputation across generations.
The challenge is not the dog. It is the closed-studbook system that has produced a genetic situation in which the Bernese now carries some of the highest cancer rates and shortest lifespans of any popular breed.
For families drawn to what the Bernese represents, three alternatives exist that preserve the temperament and presence of the breed while substantially reducing the closed-studbook genetic load.
Attribute Bernese Mountain Dog Australian Mountain Dog Unfurnished AMD Bernedoodle (F1) Median lifespan (population data) 6 to 8 years Insufficient breed-specific data; expected longer based on hybrid vigor principles Insufficient breed-specific data; expected longer based on hybrid vigor principles Insufficient breed-specific data; expected longer based on hybrid vigor principles COI (typical Stokeshire program range) 27 to 39 percent (purebred average per Bannasch 2021) 0 to 4 percent 0 to 4 percent 0 to 4 percent Cancer mortality (peer-reviewed) 55 to 58 percent of deaths Insufficient long-term data Insufficient long-term data Insufficient long-term data Adult size range 80 to 115 pounds 50 to 75 pounds 50 to 75 pounds 50 to 80 pounds Coat shedding Heavy, year-round Low to moderate Moderate to heavy Low to none Typical temperament Gentle, calm, deeply bonded Gentle, calm, family-oriented, working intelligence Gentle, calm, family-oriented, working intelligence Gentle, intelligent, family-oriented
The Australian Mountain Dog, the Unfurnished Australian Mountain Doodle, and the F1 Bernedoodle each represent intentional crosses designed to preserve the best of the Bernese temperament and family suitability while drawing genetic diversity from Australian Shepherd, Standard Poodle, and other compatible parent breeds with substantially different genetic backgrounds.
We are not arguing that families should not choose a Bernese. We are arguing that families considering a Bernese should know the lifespan and cancer data before making the decision, and that they should know intentional crossbred alternatives exist that may offer the temperament they love alongside a longer life with their dog.
This is the conversation we believe families deserve to have.
Section 6: What We Are Not Arguing
This piece will be read by people who love purebred dogs. We want to address that audience directly.
We are not arguing that purebred dogs are bad dogs. The Goldens, Bernese, Cavaliers, Boxers, Pugs, Bulldogs, and other popular breeds are loved for good reasons. They are extraordinary animals, and the families who love them are not wrong to love them.
We are not arguing that the people who breed purebred dogs are bad people. The vast majority of purebred breeders we know, including those operating under AKC standards, are passionate about their dogs and committed to responsible practices within the system they operate in. The closed studbook is a structural problem with the system. It is not a moral failing of the breeders working within it.
We are not arguing that all crossbred dogs are healthier than all purebred dogs. The 2024 study of more than 580,000 UK dogs published in Scientific Reports found that the median lifespan of purebred dogs (12.7 years) was slightly higher than that of crossbred dogs (12.0 years) in their dataset. This finding is real and worth addressing honestly. The likely explanation is two-fold: first, the "crossbred" category in that study included a wide range of dogs from random-bred mixes to multigenerational designer crossbreds, and second, the purebred category included many small breeds with natural longevity advantages while the crossbred category likely skewed toward medium and large dogs. When the comparison is restricted to genetically diverse F1 crosses from health-tested parents versus highly inbred purebreds, the lifespan advantage of genetic diversity reasserts itself, as documented in the Royal Veterinary College's primary care data and in the Kraus 2022 finding that every one percent increase in heterozygosity is associated with approximately 31 additional days of life.
We are not arguing that "doodle" automatically means healthy. The 2024 PLOS One paper titled "The doodle dilemma," which examined Cockapoos, Labradoodles, and Cavapoos compared to their progenitor breeds, raised legitimate concerns about the health of those specific designer crossbreeds. The paper deserves to be addressed directly, which we do in the next section.
What we are arguing is this: the closed studbook system that defines modern purebred breeding has produced a measurable genetic situation that compromises the health and longevity of many popular breeds. The mathematical principle of hybrid vigor offers a path to dogs with the temperament and family suitability that purebred lovers value, alongside the genetic diversity that produces longer, healthier lives. The fight is with the system. It is not with the dogs or the people who love them.
Section 7: What the Critics Will Say
We anticipate this piece will draw professional pushback. We have heard most of the responses before. Here are our answers to the ones we expect.
"Hybrid vigor is a myth in dogs."
This claim cannot be sustained against the agricultural genetics literature. Hybrid vigor is not a phenomenon specific to dogs or to one species. It is a mathematical consequence of crossing genetically distinct populations, established by Sewall Wright in the early twentieth century and codified in standard quantitative genetics textbooks. The dairy industry has spent decades proving its measurable benefits in millions of cattle. The beef industry has done the same. The principle does not pause for canines. The Bellumori 2013 study of 27,254 dogs found purebreds significantly more likely to have 10 of 24 inherited disorders compared to mixed-breeds. The mechanism is real. The evidence is published.
"Doodles have just as many health problems as purebreds. The 'doodle dilemma' paper proves this."
The 2024 PLOS One paper is real published research and we treat it with respect. It found concerning health patterns in Cockapoos, Labradoodles, and Cavapoos relative to their purebred progenitor breeds. Three responses are necessary.
First, on breed selection: the paper studies three specific designer crossbreeds. Stokeshire does not breed Cockapoos, Labradoodles, or Cavapoos. The paper's findings do not extrapolate to programs producing different crosses with different parent breeds.
Second, on generation methodology: the paper does not differentiate between F1 first-generation crosses and multigenerational doodle-to-doodle breeding. This distinction is not minor. It is the entire question. By the agricultural genetics literature, F1 crosses retain 100 percent heterosis. F2 crosses retain approximately 50 percent. Stabilized multigenerational hybrid populations retain even less, depending on the number of founder breeds and the breeding system used. A study that lumps F1, F2, F3, and multigenerational doodle-to-doodle breeding together cannot make claims about F1 crosses specifically.
Third, on breeder methodology: the paper does not differentiate between breeders who track COI, screen parents through OFA and Embark, and intentionally maintain genetic diversity in their programs versus breeders producing volume without genetic management. The paper studies crossbreed outcomes, not crossbreed programs.
The paper's findings are consistent with what the agricultural genetics literature predicts: stabilized multigenerational hybrid populations, like stabilized purebred populations, lose hybrid vigor and accumulate genetic load. This is not a refutation of F1 hybrid breeding. It is confirmation of why the F1 vs multigenerational distinction matters.
"You're cherry-picking the worst purebred examples."
This is fair to ask. The breeds we focused on — Bernese, Cavalier, Bulldog, Pug, Doberman — are popular breeds with documented severe genetic problems. They are not the only purebred breeds, and not all purebred breeds suffer to the same degree. We focused on these examples because the data is most extensive and the population-level consequences are most severe. The structural mechanism — closed studbook, genetic drift, popular sire effect, accumulated homozygosity — applies across all purebred breeds, even those where it has not yet produced the severe outcomes seen in Bernese or Cavaliers. The question is not whether the mechanism applies. It is how far each breed has progressed along the trajectory.
"AKC breed clubs are doing genetic rescue work."
Some are. The Dalmatian-Pointer outcross, initiated in 1973 and now producing dogs that are 99.98 percent Dalmatian by pedigree but carry the healthy gene for uric acid metabolism, is a genuine success story. The Finnish Kennel Club has approved outcross projects for the Cavalier King Charles Spaniel and the French Bulldog. The Norwegian Lundehund rescue project, using related Nordic Spitz breeds, has restored measurable genetic diversity to a breed that was nearly lost. These efforts deserve recognition. They are also exceptions, not the rule. Most major breed clubs continue to enforce closed studbook rules even where the genetic case for outcrossing is overwhelming. We are not arguing against the breed clubs doing genetic rescue work. We are arguing that the system, as it currently operates for the vast majority of breeds, is producing the genetic outcomes documented in the Bannasch 2021 data.
"Doodles are just designer mutts with a markup."
This critique is usually aimed at the lowest tier of doodle producers, who breed at volume without health testing, COI tracking, or any structured genetic management. The critique applies to those operations and we share it. Stokeshire is structurally different. Every parent dog in our program is screened through OFA evaluations and Embark genetic panels. Coefficient of inbreeding is calculated and tracked on every pairing. We maintain relationships with other breeders to source unrelated breeding stock specifically to prevent the closed-population drift that the agricultural literature identifies as the source of hybrid vigor decline. The distinction between commodity doodle breeding and structured hybrid programs is not a marketing distinction. It is an operational and genetic distinction that shows up in the COI numbers.
"My Bernese lived to 13."
We are happy for you, and we mean that sincerely. Outliers exist in every population. The Bernese median lifespan of 6 to 8 years means that some Bernese live longer and some live shorter. A Bernese living to 13 is a beautiful exception. The median is what owners should expect when making a decision. Population-level data is the appropriate basis for evaluating breed-level health, not individual cases. Anecdote does not change median.
"You're just trying to sell expensive doodles."
We are a commercial breeder. We have an economic interest in placing puppies. We will not pretend otherwise. What we will say is this: the argument we are making in this piece is grounded in peer-reviewed research that is publicly verifiable. Every statistical claim cites a published study. Every mathematical principle is drawn from standard quantitative genetics. The argument either holds up to scrutiny or it does not. Our commercial interest does not change the validity of the citations. If our argument is wrong, the citations are where it can be challenged. If the citations are correct, then the argument stands regardless of who is making it.
"Mixed-breed dogs end up in shelters too."
Yes. The closed-studbook critique is not an argument against responsible mixed-breed ownership or against rescue dogs. It is an argument that the structural genetic situation in popular purebred breeds is producing measurable health and longevity problems that buyers should know about when making a decision. The shelter problem is a separate issue, addressed in detail in our other published work, and it does not change the genetic data on purebred lifespans and disease burden.
Section 8: What You Can Do
“The choice is not ‘purebred or hybrid’ or ‘breeder or rescue.’ The choice is ‘operation with structural accountability for the dog’s health outcomes, or operation without it.”
For families considering a dog, three paths forward are available.
If a particular purebred breed represents something irreplaceable to you — a family tradition, a working role, a specific aesthetic — that is a valid reason to choose that breed. We would only ask that you do so with eyes open. Ask the breeder for the dog's COI from genomic testing, not just pedigree-based estimates. Ask what specific health conditions are documented in the line. Ask what the breeder's policy is if a serious genetic condition emerges in the dog's first years. These questions distinguish breeders working within the closed-studbook system who are managing for health from those who are not.
If you are open to an intentional crossbreed program, evaluate the program by the same criteria. COI tracking on every breeding dog. Health testing through OFA and Embark on every parent. A clear position on whether the program breeds first-generation crosses or multigenerational hybrids, and why. Documented introduction of new breeding stock from unrelated sources. The same questions that distinguish a structured purebred program distinguish a structured hybrid program.
If you are working with a rescue organization, the questions are different but equally important. Rescues often have less information about a dog's genetic background, but they can speak to the dog's temperament, behavioral history, and known health considerations. Rescue is a path of accepting some uncertainty about background in exchange for giving a home to a dog who needs one.
The choice is not "purebred or hybrid" or "breeder or rescue." The choice is "operation with structural accountability for the dog's health outcomes, or operation without it." That distinction is what matters.
Section 9: Why We Are Building the Stokeshire Dog
Stokeshire Designer Doodles is our life's work. The program exists because we believe a different model of dog breeding is possible — one grounded in the agricultural genetics literature that has guided commercial animal breeding for the last century, applied to the species we share our homes with.
The Stokeshire Dog is not one breed. It is a structured program of intentional hybrid breeding across multiple parent breeds — Bernese Mountain Dog, Standard Poodle, Australian Shepherd, Golden Retriever, and others — with active management of coefficient of inbreeding, ongoing introduction of unrelated breeding stock, prioritization of first-generation crosses, and lifetime accountability for every dog we produce.
This is the model we are committed to. It is more operationally expensive than commodity doodle breeding. It is more genetically diverse than closed-studbook purebred breeding. It is structured around the principle, established in the agricultural literature and confirmed across millions of cattle and decades of research, that genetic diversity produces measurable improvements in longevity, health, and fitness.
We do not claim our model is the only valid approach to thoughtful dog breeding. Other breeders, in both purebred rescue programs and intentional hybrid programs, are doing meaningful work. We claim only that the model we are building is grounded in the peer-reviewed literature, verifiable in our actual COI numbers and health testing records, and aimed at producing dogs that live longer and healthier lives than the closed-studbook system has been producing.
This piece is not a marketing document. It is a position paper describing what we believe and why we believe it. The science is in the citations. The operational reality is in our records. The dogs are in the homes of more than 548 families across 38 states and 6 countries. The case for the Stokeshire Dog rests on those three foundations.
Section 10: Citations
Bannasch, D., Famula, T., Donner, J., Anderson, H., Honkanen, L., Batcher, K., Safra, N., Thomasy, S., & Rebhun, R. (2021). The effect of inbreeding, body size and morphology on health in dog breeds. Canine Medicine and Genetics, 8(1), 12. PMID: 34852838.
Bellumori, T. P., Famula, T. R., Bannasch, D. L., Belanger, J. M., & Oberbauer, A. M. (2013). Prevalence of inherited disorders among mixed-breed and purebred dogs: 27,254 cases (1995-2010). Journal of the American Veterinary Medical Association, 242(11), 1549-1555. PMID: 23683021.
Cundiff, L. V., Gregory, K. E., & Koch, R. M. (1998). Composite breeds to use heterosis and breed differences to improve efficiency of beef production. USDA Agricultural Research Service Technical Bulletin.
Erich, S. A., Rutteman, G. R., & Teske, E. (2013). Causes of death and the impact of histiocytic sarcoma on the life expectancy of the Dutch population of Bernese Mountain Dogs and Flat-coated Retrievers. The Veterinary Journal, 198(3), 678-683.
Falconer, D. S., & Mackay, T. F. C. (1996). Introduction to Quantitative Genetics (4th ed.). Pearson Education Limited.
Heins, B. J., Hansen, L. B., & Seykora, A. J. (2006). Production of pure Holsteins versus crossbreds of Holstein with Normande, Montbéliarde, and Scandinavian Red. Journal of Dairy Science, 89(7), 2799-2804.
Klopfenstein, M., Howard, J., Rossetti, M., & Geissbühler, U. (2016). Life expectancy and causes of death in Bernese Mountain Dogs in Switzerland. BMC Veterinary Research, 12, 153.
Kraus, C., Snyder-Mackler, N., & Promislow, D. E. L. (2022). How size and genetic diversity shape lifespan across breeds of purebred dogs. GeroScience, 45(2), 627-643. PMID: 36066765.
Lewis, T. W., Abhayaratne, B. M., & Blott, S. C. (2015). Trends in genetic diversity for all Kennel Club registered pedigree dog breeds. Canine Genetics and Epidemiology, 2(1), 13. DOI: 10.1186/s40575-015-0027-4.
McMillan, K. M., Bielby, J., Williams, C. L., Upjohn, M. M., Casey, R. A., & Christley, R. M. (2024). Longevity of companion dog breeds: those at risk from early death. Scientific Reports, 14, 531.
Michell, A. R. (1999). Longevity of British breeds of dog and its relationships with sex, size, cardiovascular variables and disease. Veterinary Record, 145(22), 625-629. PMID: 10619607.
O'Neill, D. G., Church, D. B., McGreevy, P. D., Thomson, P. C., & Brodbelt, D. C. (2013). Longevity and mortality of owned dogs in England. The Veterinary Journal, 198(3), 638-643. PMID: 24206631.
Packer, R. M. A., O'Neill, D. G., Fletcher, F., & Farnworth, M. J. (2024). The doodle dilemma: How the physical health of 'Designer-crossbreed' Cockapoo, Labradoodle and Cavapoo dogs compares to their purebred progenitor breeds. PLOS ONE, 19(8).
Ruple, A., & Morley, P. S. (2016). Risk factors associated with development of histiocytic sarcoma in Bernese Mountain Dogs. Journal of Veterinary Internal Medicine, 30(4), 1197-1203.
Safra, N., Schaible, R. H., & Bannasch, D. L. (2006). Linkage analysis with an interbreed backcross maps Dalmatian hyperuricosuria to CFA03. Mammalian Genome, 17(4), 340-345.
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