Genetic Diversity

A Comprehensive Genetic Analysis for Dachshund Breeders and Owners

Genetic diversity is the cornerstone of the long-term health and survival of any dog breed. A population with a broad range of genetic variation is better equipped to avoid inherited diseases and adapt to future challenges. To provide a roadmap for the future of the Dachshund in the UK, the Royal Kennel Club has released six detailed population analyses covering each of the coat types and sizes. You can read the individual reports from the links below.

These reports offer a deep dive into breeding practices, litter trends, and the "effective population size" (Ne) of our breed. Here is what every breeder and owner needs to know to ensure these varieties thrive for generations to come.

Understanding the Genetic Toolkit

Before looking at variety-specific data, it is important to understand the metrics used to measure genetic health:

Coefficient of Inbreeding (COI): This measures the probability that a dog has inherited the same copy of a gene from both parents because they share common ancestors.
Effective Population Size (Ne): This represents the number of individuals in a "theoretical ideal population" that would lose diversity at the same rate as the real-world breed. An Ne of less than 50 places a variety at critical risk of inbreeding depression, while an Ne over 100 is considered more sustainable.
Average Genetic Relationship (AGR): While COI looks at a specific litter, AGR measures how closely an individual dog is related to the entire breed population. Dogs with a low AGR are genetically "rare" and highly valuable for maintaining diversity.

The State of the Six Varieties

Each variety of Dachshund faces a unique set of demographic and genetic challenges.

Standard Smooth Haired

The Standard Smooth Haired Dachshund population has more than doubled since 1990, but the variety is considered at critical risk of inbreeding depression. Its effective population size is estimated at just 43, which is well below the safety threshold of 50. Breeders are encouraged to prioritise mating pairs that are as unrelated as possible to pull the variety back from this danger zone.

Miniature Smooth Haired

This variety has seen explosive growth, with registrations jumping from 1,172 in 1990 to 14,566 in 2021. Despite this large pool, selection intensity remains high; only 8.1% of national males born in 2015 have been used for breeding to date. This narrows the gene pool unnecessarily. On a positive note, its Ne is a robust 339, which is considered highly sustainable.

Standard Long Haired

The Standard Long Haired population has almost halved since 1990, falling from 425 annual registrations to 214. This decline has led to a high level of relatedness; the average dog in this variety is more related to its peers than first cousins. Because of the heavy influence of imported dogs with shallow pedigrees, a reliable effective population size cannot currently be calculated.

Miniature Long Haired

The Miniature Long Haired variety has grown in popularity since 2019. With an Ne of 137, it is currently in a sustainable position. However, breeders should be aware that there is a significant negative link between inbreeding and fertility in this variety: a 10% increase in COI is associated with a reduction in litter size.

Standard Wire Haired

This variety has experienced a significant increase in size, with registrations rising by an average of 18.5 dogs per year since 1990. While the population is numerically strong, there is evidence of the popular sire effect, where a small number of males produce a disproportionate number of puppies.

Miniature Wire Haired

The Miniature Wire Haired population has fluctuated over the last 30 years. Like the Long Haired and Standard Wire varieties, its inbreeding rate appears "negative" due to the high use of imports, making an Ne calculation impossible. Breeders have reduced COIs in "pet" litters, but purpose-bred litters (from parents with stud book numbers) still maintain higher levels of inbreeding.

The Danger of the "Popular Sire"

One of the greatest threats across almost all Dachshund varieties is the over-use of a single male dog, known as the Popular Sire Effect. When one dog is used far more than others, his genes and any harmful recessive variants he carries spread rapidly through the breed.

In several varieties, sires with stud book numbers are used significantly more often than those without. For example:

In Miniature Smooth Haireds, sires with stud book numbers produce an average of 15 litters, compared to 7 for those without.
In Miniature Long Haireds, they produce 10 litters compared to 5.

To protect the breed, the Royal Kennel Club recommends that no single dog should dominate the gene pool and that breeding should be spread across as many different males as possible.

The Link Between Inbreeding and Litter Size

For the first time, these reports explore how inbreeding affects the health and fertility of Dachshunds. In five of the six varieties (all except the Standard Long Haired), there is a significant and negative association between COI and litter size.

Miniature Smooth Haired: A 10% increase in COI reduces litter size by 0.5 puppies.
Standard Smooth Haired: A 10% increase in COI reduces litter size by 0.4 puppies.
Miniature Wire Haired: A 10% increase in COI reduces litter size by 0.3 puppies.

This phenomenon, known as inbreeding depression, can lead to reduced fertility and overall survival if left unmanaged.

The Role of Imported Dogs

Imports are often seen as a way to "refresh" the gene pool. Indeed, the use of imported dogs has increased across all varieties. However, breeders must exercise caution. Imported dogs often have "shallow" pedigrees (only 3 generations), which can hide the fact that they may share ancestors with UK lines further back. If they share recent ancestors, the added diversity they provide may be limited.

Recommendations for Breeders

To ensure the long-term health of Dachshunds, breeders should consider the following actions:

Monitor the AGR: Look for dogs with a lower-than-average genetic relationship to the breed, as these carry the rarest genes.
Avoid repeat matings: Don't rely on the same "proven" sires; instead, look for quality males that have been under-utilised.
Aim for sustainability: Ideally, the rate of inbreeding in a breed should increase by no more than 1% per generation.
Research imports: Ensure an imported dog is truly from a distinct lineage before assuming it will add diversity.

By making informed, evidence-driven decisions, we can ensure that every variety of Dachshund remains as healthy and viable as possible. Dachshund breeders should also read about the RKC's Breeding for Health Framework and the checklists we have created.