Kromfohrländer vom Hamburger Elbstrand
Zuchtstätte für glatthaarige Kromfohrländer

Crossbreeding in Pedigree Dogs

The aim of an incrossing project is to increase the genetic diversity, which is severely limited in the closed population of a breed. The reproductive community of the Kromfohrländer is comparatively small and has developed from only three founding animals. Peter and Fiffi had seven litters between 1947 and 1954, from which nine dogs were entered in the studbook, three of which had offspring with studbook entries and were therefore bred further. These probably had a very high genetic variance, because their parents were very far apart in terms of relationships, as is usually the case with dogs of different breed compositions. They also had a uniform appearance, which defined the basis of the first breed standard. As described under "The Kromfohrländer" and "Genetics", there were deviations from this standard in the following generations, so that selections were made at an early stage. Only the “typical” Kromfohrländer were used for further breeding, so that the genetic diversity continued to decrease. The only “refresh” came in 1960 with the pedigree Fox Terrier female Elfe. Since then, breeding has taken place in a closed population until the first incrossing project took place 50 years later.

Even today (2024) dogs are excluded from breeding in many breed clubs, including those in Kromfohrländer, based on purely optical criteria. Be it because they have the “wrong” color, which can be easily controlled with the help of genetic tests. Or because they are not rough-haired. As is well known, both of these led to major losses in the gene diversity of the already small population when our race was created. The often heard argument that mixed matings between rough and smooth lead to a loss of rough hair quality should probably be long outdated given today's knowledge of the genetic basis, especially since the founding mating was already such a mixed mating: Peter was rough-haired, and from Fiffi is known that she was smooth and short-haired, as well as black and white, so confirmed by Ilse Schleifenbaum's son and contemporary witness Dr. Henrich Schleifenbaum. Softer, non-trimmable fur occurs equally in pure rough-haired as well as in mixed matings. How the fluffy fur, which is not typical of the breed, comes about is also known; interestingly, these dogs are always purebred rough-haired. More about the inheritance of coat colors and structure can be found HERE. Prof. Dr. Achim Gruber recommends in his highly acclaimed book “Geschundene Gegenossen”, published in 2023, such mixed matings, and not just for our Kromfohrländer, in order to avoid too close a relationship between the parents. From our genetic analyzes we know that rough-haired Kromfohrländer are significantly further removed in their genetic relationship from smooth-haired representatives than from dogs with their own coat structure. Basically and of course, when mating, the health of the offspring should always be more important than external appearance or even show success.

Genetic Variance - What does that actually mean?

The preservation of the genetic variance as one of the most important goals of modern dog breeding is a frequently heard and widely accepted claim to current breeding strategies. However, the implementation of this requirement is often associated with great difficulties, especially in today's breed populations, and is sometimes not possible without accepting more or less extensive restrictions for other breeding goals. Very often, therefore, the classic and proven breeding strategies of selection and line breeding outweigh individual breeding decisions. The associated reduction in genetic variance is accepted - very often because the advantages of maintaining genetic variance are not as clear and obvious as the advantages of mating under aspects of selection breeding.

And fatally, it is actually the case that the advantages of maintaining variance primarily affect the population in the longer term, while the advantages of an individual selection or mating decision are expressed directly in the phenotypic quality of the offspring. And just as fatally, breeding decisions that are in the interest of the health of the offspring often exacerbate the situation of genetic diversity.

The problem is that any form of selection means that certain animals are not used for breeding, while others are used to an increased extent. And that automatically leads to an increase in homozygosity and thus a reduction in the genetic variance in the population. The basis on which a selection decision was made is irrelevant. This means that both the preference for a particular male due to the success of his exhibition and the exclusion of another male due to an unfavorable HD or eye condition basically have the same effects on genetic diversity.

However, the basic problem of modern breed populations is clearly obvious. Most breeds are exposed to one or more genetic health problems to a greater or lesser extent. And in every breed there is a more or less intensive selection for form, performance and, more recently, for essentials.

It is therefore almost the same as squaring the circle to reconcile the demand for the preservation of genetic diversity with the equally diverse selection breeding goals. The only way to solve this problem halfway successfully is to develop breed-specific breeding strategies that take into account the individual situation of the individual breed populations and exploit all the possibilities of modern genetics. In any case, a task that can hardly be solved without the appropriate advice for breeding associations.

Imagine a tool box. It is a spartan tool kit, cheap offer from a cheap discount store. And this toolbox contains each tool only in a certain size or shape. A screwdriver, wrench, hammer, pliers, nails and screws all in one size. Sure, you can't do much with a toolbox like this. It may be suitable for minor repairs or for work in which exactly the existing tools are suitable, but it is simply unsuitable for any more demanding work.

Now imagine another box. It is well equipped. Contains every tool in all common sizes and variants. Obviously, with such a tool box, you can easily do all manual work.

Between the very spartan equipped box and the elite tool range there are of course also intermediate stages with more or less complete selection of sizes and variants. But one thing is clear: the larger the selection of tools of different sizes and shapes, the more diverse the possible uses of the tool box.

And that's exactly how it looks with the genetic makeup. To put it simply, genes are nothing more than assembly instructions for proteins of various functions, which are practically the tools that the organism needs to function. And the larger the selection of these genetically coded tools, the better the organism works under the most varied of conditions. Spartan organisms - those with low genetic variance, which have all the necessary tools, but each only in a very specific shape or size, can work under certain conditions. Namely, when exactly the right and suitable tools are available for the respective environment. However, if the environment changes, and with it the requirements placed on the tools, malfunctions occur - the animal becomes ill.

(...) Let's take a hypothetical example: An enzyme that is responsible for providing energy for the work of the muscles occurs in two variants, which differ in their temperature sensitivity. Variant A works best in a body temperature range between 36.5 ° C and 38.2 ° C, variant B has its environmental optimum in a temperature range between 37.4 ° C and 39 ° C. Both enzyme variants lose activity when the body temperature rises or falls above or below their individual optimal range of action. In a dog that is homozygous for variant A, the enzyme and thus the energy supply to the muscles will work as long as their body temperature does not exceed 38.2 ° C. With slight fever, this dog will show a more or less pronounced weakness of the muscles. A dog that is homozygous for variant B, on the other hand, will react to hypothermia that lowers its body temperature to below 37.4 ° C with muscle weakness. The best cards have a heterozygous dog that has both variants of the enzyme. He will be able to use his full muscle strength both at a slightly lower and at a slightly higher body temperature. (...)

The greater the variety of tools that an organism possesses, the better it can properly deal with changing environmental conditions. In practice, this means that a dog e.g. copes better with feed changes, copes better with infections, but can also cope better with stress or psychological stress.

What applies to the individual animal also applies analogously to a population. The greater the genetic diversity in a population, the better a population copes with changes in the environment. Any intensive selection of local or current environmental conditions, on the other hand, leads to adaptation problems if these conditions change.

The problems that arise from the lack of adaptability of the dog organism to changing environmental conditions are already everyday life in veterinary practice. So the sometimes frightening increase in immunological problems of various kinds can certainly be seen at least partly in a causal connection with increasing genetic impoverishment of many pedigree dog populations. Fertility disorders and reduced life expectancy, as well as the constantly increasing frequency of genetic defects, are to be interpreted as consequences of genetic impoverishment.

What does the solution look like now? As with most other breeding problems, there is no one-size-fits-all solution. The path of uncritical outcross or the waiving of any form of selection or line breeding, which is demanded by some, may be an approach, but certainly not in the sense of preserving pedigree dog breeding.

If you want to keep the breed of dogs as such, it is necessary to work out specific approaches tailored to the respective population situation for each breed population.

There are a number of breeding tools that can be used in this context. These include classic instruments such as the consideration of the inbreeding coefficient or the ancestor loss coefficient when selecting the mating partners, breeding limits for males, enlargement of the breeding population through immigration from other populations (such as our crossbreeding project), but also newer methods, which include can also be used to preserve genetic variance. These include methods of breeding value estimation, selection based on a selection index, use of molecular genetic diagnostic methods or instrumental semen transfer (the latter, for example, for mating dogs with a very large spatial distance, in which closer kinship is less likely, or after preserving sperm via fertility of the stud dog, if you can have more precise information about his health in older age or his life span).

When used sensibly and carefully, all of these breeding methods offer the possibility of maintaining or even expanding the genetic variance of a population as much as possible, while taking other breed-specific breeding goals into account.

(Dr. Irene Sommerfeld-Stur)

Occasionally, the argument arises that crossing another breed brings new diseases into the population. To minimize this risk, every dog ​​used in the breeding does a DNA analysis at Genoscoper in Finland, as do all puppies born at ProKromfohrländer. As an example of such a genetic test, here is Doola's test result:

MyDogDNA Doola
DNA-Test Doola-2018.pdf (224.48KB)
MyDogDNA Doola
DNA-Test Doola-2018.pdf (224.48KB)


However, not all diseases are genetically identifiable. So far, we can only contain the occurrence of epilepsy, autoimmune diseases and other conditions by observing the individual lines and carefully selecting the breeding animals. Many diseases, especially autoimmune diseases, are multifactorial, which means that the triggers can be genetic, environmental and nutritional in nature or the result of other, not always clear circumstances. However, we are clear about the fact that too little genetic diversity leads to an increased occurrence of such findings.

In addition to the usual health examinations (DNA test, blood count, COLA test ...), crossbreed dogs of all F-generations also undergo an X-ray examination for hip dysplasia, which occurs occasionally with the Danskis. Of course, we only use Danskis, which in turn are free of HD, but since the inheritance is quite complex, we do not take any risks and examine all project dogs, even if they are not are not used in breeding. The puppy buyers pay a "deposit" on acceptance, which they get back when they have their dogs examined.

Here you can find more information about crossbreeding in breeding in a report by Dr. Sommerfeld-Stur in the dog magazine Wuff (10/2014) and Genetic diversity - a fountain of youth for breeding populations (Wuff 05/2014)

Crossbreeding Project Kromfohrländer x Dansk Svensk Gardhund (DSG) at ProKromfohrländer e.V.

The following is essentially and with kind permission taken from the relevant page of ProKromfohrländer:

In our crossbreeding project a Kromfohrländer is mated with a Dansk Svensk Gardhund. The offspring (F1 generation) in turn achieve successive offspring with appropriate selection with purebred Kromfohrländer (F2 - F4 generation). In the F4 generation, suitable dogs are then selected that are similar in nature and appearance to the Kromfohrländer. These dogs are then fed to the Kromfohrländer breeding as purebred breeding animals.

F1 generation (mating Kromfohrländer x Dansk Svensk Gardhund)

50% Kromfohrländer / 50% DSG (like our A-litter)

F2 generation (mating F1 dog x purebred Kromfohrländer)

75% Kromfohrländer / 25% DSG (like our C-litter)

F3 generation (mating F2 dog x purebred Kromfohrländer)

87.5% Kromfohrländer / 12.5% DSG

F4 generation (mating F3 dog x purebred Kromfohrländer)

93.75% Kromfohrländer / 6.25% DSG

Anneliese vom Hamburger Elbstrand (F1-Projektkromfohrländer) and her mother Doola von Crumps Mühle (Kromfohrländer)

Example for a crossbreeding Project (3 pairs are assumed)

F0 generation

3 Kromfohrländer

F1 generation

 6 + 7 + 6 = 19 Projektkromfohrländer (50%), selection for further breeding: 7

F2 generation

6 + 6 + 10 + 4 + 7 + 6 + 5 = 44 Projektkromfohrländer (75%), selection for further breeding: 15

F3 generation

approx. 90 Projektkromfohrländer (87.5%), selection for further breeding: 10

F4 Generation

approx. 60 Projektkromfohrländer (93.75%), selection for further breeding: 10

This numerical example clearly and not unrealistically shows how much the number of project dogs can grow. As different and not too closely related Kromfohrländer must be found in the pairings for backcrossing, 15 different Kromfohrländer partners would be required in the example shown above for the dogs of the F2 generation. From the F3 generation onwards, the selection should be strictly limited to a maximum of 10 animals, because otherwise it will be increasingly difficult to find enough different Kromfohrländer for backcrossing.

Coffee (F2) and his mother Anneliese (F1) vom Hamburger Elbstrand

The following criteria should then be met for the F4 dogs:

1. High level of heterozygosity
2. Healthy, robust and vital animals
3. Genetically different, if possible
4. Balanced in nature and not overly sensitive and corresponding to a Kromfohrländer (little hunting instinct, strong human orientation)
5. Phenotypically like a Kromfohrländer
These criteria should apply approximately for guidance when selecting in the generations.
For the assessment of heterozygosity, the inclusion of genetic studies is planned. The participation in the pilot project (genome-wide analysis) of the Finnish company Genoscoper was a first step.

(Extract from a report by Dr. Sigrun Bennemann, April 2013)


Note: Today, all Kromfohrländer in the breeding at Prokromfohrländer have to show an extensive genetic test, as it is offered at Genoscoper in Finland (MyDogDNA), both in the crossbreeding project and in pure-bred breeding.

Why the Dansk Svensk-Gardhund?

ProKromfohrländer came to the conclusion that the Dansk Svensk Gardhund is currently best suited for the crossbreeding project because it combines the most advantages.

When choosing a suitable breed, great emphasis was placed on health, longevity and a balanced nature. But also size, physique and proportions should be similar, whereby the exterior was at the bottom of the priority list, because the external appearance, i.e. everything that you see at first glance on a dog, is relatively easy to influence in breeding.

It is different with the characteristics and the state of health; it gets a lot more complicated here because these traits depend on many different genes and factors.

The Dansk Svensk Gardhund, which can often be found in Denmark and Sweden and the number of which is also increasing in Germany, is a small, robust pied farm dog that can get quite old. It is bred more for usability, sportiness and simplicity than for beauty. This has certainly contributed to the fact that so far there are few health problems in this breed. Only the juvenile femoral head necrosis has been found in some dogs of this breed. However, this disease becomes noticeable at a very early age, so that the affected animals are never used for breeding. In addition, strict breeding control measures to combat this disease are carried out in Sweden and Denmark.

The Dansk Svensk Gardhund breed is also relatively healthy in comparison to many other dog breeds, because it is endowed with a large genetic variance as a young land breed. Numerous ancestors have entered the breed, and suitable dogs have also been added to the further breeding. In contrast to mixed breeds, extensive health and family tree data are available. There is therefore a high level of knowledge about the general health situation of this breed.

Another crucial advantage is the nature of the Danskis. It does not belong to the group of terriers, but rather belongs to the category of the Pinscher. In essence balanced and very friendly towards dogs, children and people in general, he will help that the rather nervous and sensitive Kromfohrländer gains more stability and security.


Doola von Crumps Mühle (Kromfohrländer) with Anneliese vom Hamburger Elbstrand (F1-Projektkromfohrländer)

As a farm dog, the Danski tends to recreate mice and rats, which are often found by digging them up. However, this behavior can be found in many dogs, including some in our Kromfohrländer. One should keep this behavior in mind with the offspring offspring. Like the Kromfohrländer, the Danski otherwise has little hunting instinct. This is very crucial, because essentials are difficult to breed out.

The exterior of the Danski often resembles a smooth-haired Kromfohrländer, only that it is a little smaller and usually more powerful. This could have a more favorable effect on Kromfohrländer breeding, since relatively large Kromfohrländer have been born in recent years. In fact, our A-dogs (F1) and our C-dogs (F2) no longer differ in size from the Kromfohrländer.

The short, smooth fur of the Danskis is also a plus when crossed. This hair variant is already known in the Kromfohrländer breeding, so that basically nothing new is brought into the breed in this regard. The occasional breeding use of short-smooth dogs is even recommended for wire-haired breeding, because this improves the quality of the fur in the medium-length wire-haired variant, and the fur gets more density again. Since the shaggy hair quality is dominant compared to the smooth-hair, just as the beardedness towards the characteristic "without a beard", after crossing with a Danski you can easily achieve dogs with medium-length shag hair and also short-haired ones with a beard.

The C-Litter vom Hamburger Elbstrand

In the smooth hair breeding of Kromfohrländer, the short, smooth variety is already being used to prevent the gene pool from becoming even smaller. The smooth hair breeders already have experience with the use of short, smooth dogs. This makes it clear that crossbreeding with a Danski also Benefits rough-haired and smooth-haired breeding. In particular, the genetically more restricted smooth hair breeding could benefit greatly from the crossbreeding measure. Here the project can become an important way out, because in the meantime, due to the high degree of relationship, it is hardly possible to find responsible pairings. This situation is exacerbated due to the large number of "von Willebrand syndrome" carriers in both hairstyles.

A genetically healthy dog ​​breed of the future requires sustainability and perseverance and not rapid breeding success through the use of dangerous inbreeding. ProKromfohrländer e.V. would like to take this path for the rough and straight hair variety of the Kromfohrländer and thus enable the breed a future. The first crossbreeding project will be an important milestone in this direction. Choosing the Dansk Svensk Gardhund as a foreign breed is a very considered step that will result in a higher genetic diversity. The risk of undesirable changes in the Kromfohrländer as well as the introduction of new diseases is kept as low as possible. The continuous control and observation of the crossbreeding project and targeted selection also in the further course will also work in this direction.


Doola von Crumps Mühle (Kromfohrländer) and her daughter Anneliese vom Hamburger Elbstrand (F1-Projektkromfohrländer)

We would like to expressly point out that we cannot guarantee healthy dogs within our crossbreeding project either. For example, an autoimmune disease has recently occurred in a second generation dog. Such and similar cases will continue to exist, but we can assume that the likelihood of this will explicitly decrease due to genetic refreshment.

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