How Inbreeding is Threatening the Genetic Health of Airedale Terriers

 

The use of genetic data to estimate inbreeding between two dogs (using Embark’s Pair Predictor) reveals that even seemingly unrelated Airedales from different continents, on average, share 40% of their genes that are identical by descent from both their dam and sire. This is measured by the genetic coefficient of inbreeding (gCOI), which specifically calculates the proportion of a dog’s genome where the dam’s and sire’s genes are the same due to common ancestry – excluding fixed canine and breed-typical genes. Without the introduction of new, unrelated lines or breeds, this diversity will continue to shrink.

 

The Airedale Terrier is not just facing a challenge, it’s approaching a crisis. While the full impact may not be seen immediately, urgent action is needed to ensure the breed thrives for generations to come.

 

This isn’t just an Airedale issue – many other breeds, including but not limited to the Boxer, Rottweiler, German Shepherd, and Doberman, face similar genetic challenges. Most breeders are unaware of the dangers lurking if changes aren’t made.

It’s not just about the numbers; I’m deeply concerned about the long-term health implications of inbreeding. Many breeders have raised concerns with me about the increasing prevalence of autoimmune diseases like Addison’s and other genetic disorders like PLN (Protein-Losing Nephropathy). The spread of these diseases directly results from inbreeding and a lack of sustainable breeding strategies.

 

According to Kristensen and Sørensen (2005), inbreeding has harmful effects that reduce genetic variability, directly impacting reproductive success and overall health. The study noted increased mortality rates and decreased adaptive capacity, reinforcing that inbreeding is not a tool for preserving breeds but a destructive practice leading to genetic decline.

Further, Pryce et al. (2014) found that inbreeding causes inbreeding depression, reduced fertility, increased mortality, and poorer productivity in livestock. For every 1% increase in inbreeding based on pedigree or genomic data, the animals experienced measurable declines in health and performance. This mirrors what happens in dogs, where reduced genetic diversity through line breeding has similar negative effects.

Pedersen et al. (2015) demonstrated how inbreeding in Standard Poodles significantly increased autoimmune diseases like Addison’s. The study identified genetic bottlenecks caused by the overuse of popular sires as the root cause of these issues. It also linked inbreeding to reduced immune related gene diversity, making breeds more susceptible to diseases.

 

Additionally, inbreeding compromises immune function. As genetic diversity is lost, so is variation in immune system genes, making animals more vulnerable to infections and autoimmune disorders.

 

A 2016 study on Scandinavian wolves by Åkesson et al. showed how inbreeding weakened immune systems, increasing disease susceptibility. However, the introduction of just one unrelated wolf had a significant positive impact on the genetic diversity of the population, increasing genetic variation and improving overall health. This demonstrates how even a small introduction of new genetic material can profoundly affect a population’s genetic diversity.

 

Recent research, such as Bannasch et al. (2021), shows that inbreeding increases the prevalence of genetic disorders like epilepsy and heart disease in dogs. The study emphasises that high levels of homozygosity – a consequence of inbreeding – are associated with shorter lifespans and complex inherited diseases. The notion that outcrossing introduces new problems is a dangerous myth. In reality, outcrossing increases genetic diversity and prevents the expression of harmful recessive traits. Alarmingly, the study found that the Airedale Terrier is one of the most inbred breeds in the world. The same study also found that many other breeds face the same challenge – for instance, but not limited to – working breeds like Boxer, Doberman, German Sheperd and Rottweiler.

Breeders who cling to line breeding are not preserving the breed; they are driving it toward a future of genetic decline. While these effects may not be apparent today, they are accumulating. Many breeders argue that outcrossing causes diseases to emerge because it supposedly reduces control over breeding stock. Outcrossing, or breeding between unrelated individuals, DOES NOT cause new mutations to appear. In fact, mutations arise due to spontaneous errors that occur naturally during DNA replication, regardless of breeding methods. These random mutations are a normal part of genetic variation in all living organisms.

However, in populations with a narrow gene pool – like those subjected to inbreeding or line breeding – there is a higher risk of amplifying harmful recessive mutations. This is because the reduced genetic diversity increases the likelihood that both parents carry the same harmful mutations, which can then be passed on to offspring.

 

By introducing greater genetic diversity, outcrossing helps dilute harmful recessive mutations already existing in a narrow gene pool. It increases the likelihood that healthy, non-mutated genes from one parent will mask or override harmful mutations from the other. Therefore, rather than causing mutations, outcrossing helps reduce the expression of harmful recessive traits, promoting healthier, more genetically diverse populations.

 

Even siblings from the same litter are genetically distinct due to genetic recombination, where genetic material from both parents is shuffled during the formation of reproductive cells. This means each sibling inherits a unique combination of genes, creating diversity even among dogs with the same parents. Therefore, as a general rule, FCI recommends that a breeding programme should not exclude more than 50% of the breed. Thus, the breeding stock should be selected from the best half of the breed population. Unfortunately, we are far from achieving this goal.

It’s time for all breeders to step up and make a difference. Many breeders focus too heavily on top-performing sires, causing inbreeding in future generations. But this can change. Healthy, thriving dogs – not show ribbons – should be the goal. Breeding for function and health must take priority over appearance. We must include more dogs in breeding programs, be transparent about health, and avoid line breeding to prevent genetic decline. Sustainable breeding practices should be our focus – preserving genetic diversity for the long-term health of the breed. Let’s focus on what truly matters – breeding dogs with strong health, good temperaments, and the ability to function according to their breed’s purpose, ensuring the vitality and sustainability of future generations.

 

In the Nordic countries , breeders are slowly – one by one – shifting focus toward new breeding strategies, and I believe we’ll see a significant change in attitudes toward dog breeding within the next ten years or so. Together, we can ensure a brighter future for our beloved breeds, one responsible decision at a time.

 

Please join the European Airedale Breeders group on Facebook, where we have valuable discussions regarding Airedale Terriers’ health, temper, and outline. https://www.facebook.com/groups/768707324041656

 

I urge everyone passionate about the health and sustainability of dog breeds to join the Facebook group” Rhodesian Ridgeback Health and Long-term Sustainable Breeding”. The author of this text is an active member of this group, and we warmly welcome owners of other breeds to join. We have shared scientifically validated information that could guide breeding practices and have had several good discussions. This is the place to join for those willing to acknowledge that the world is evolving or those still unconvinced but want to learn more. https://www.facebook.com/groups/rhodesianridgebacksustainablebreeding/

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