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Avoiding the genetic defect DS and enlargement of the gene pool...

Personal thoughts on the breeding of our breed and the use of ridgeless ridgebacks to avoid the genetic defect Dermoid Dinus and expanding of the gene pool

In 2008, when I applied for the breeding program to prevent the Dermoid Sinus from the VDH as the first chairman of Club ELSA, and the VDH approved the use of ridgeless Ridgebacks for this purpose, it was not clear to me how massive the resistance in the Ridgeback world (especially in Germany) would be. That there are people who fight against breeders with all means, for whom the health of the breed, the fight against a genetic defect and the expansion of the gene pool is important - I would never have thought of this.

But from the beginning…

Even the longest way starts with a first step ... I took this first step when I got my foundation bitch Beris Bilé Karpaty "Kimba" as a puppy in 1998. I was fascinated by the Rhodesian Ridgeback since I saw some dogs of this breed live for the first time. This fascination has remained until today.

At that time it was absolutely not uncommon, that ridgeless Ridgebacks are killed immediately after birth - a fact that shocked me even then. Also the puppies with Dermoid Sinus (DS), an inherited genetic defect, were mostly put to sleep - indeed not in Germany, but in many other countries it was required (not only recommended!) by the Clubs to kill ridgeless puppies and puppies with DS.

If there were no regulations on the part of the Clubs, the decision was made by the breeder. In the case of puppies with DS, it was often argued that there was no specialized veterinarian who could make the surgery (which was certainly the case in some countries). Often the surgery would have been too expensive, so the breeders therefore decided to put these puppies to sleep.

The reason to put a ridgeless puppy to sleep was as simple as it was unbelievable: they missed the Ridge,so it was very difficult to sell, because ... .. a Ridgeback without a Ridge is (according to many) not a real Ridgeback.

So healthy puppies were killed because the only miss a mutation - a mutation that can result in the genetic defect Dermoid Sinus. Because of this genetic defect, the Rhodesian Ridgeback is in Germany listed in the “agony breeding report” issued in 1999 (report on the interpretation of Section §11b of the Animal Welfare Act), together with numerous other breeds, which are now even prohibited to be bred in some countries.

The THURAIA-Breeding

... started in 2001 with Kimba’s first litter. We had 8 puppies - all with Ridge, but unfortunately two of them had a DS. As a first breeder it was a terrible experience for me and I actually considered to stop breeding because I just didn't want to breed dogs with a genetic defect. Of course -the DS could be operated and that was done with these two puppies at the age of 5 months, but was there no other option?

This first litter with the two DS puppies lead to that I dealed with the topic in more detail.

The Dermoid Sinus

Already in the first publications of our breed the Opens external link in new windowDermoid Sinus was documented (T.C. Hawley - The Origin, History and Standard from 1957) and killing of ridgeless Ridgeback puppies was absolutely not a taboo subject but common practice - worldwide. The more I dealt with the topic, the more intense my thirst for knowledge about the background and the more important it seemed to me that I had to do something.

In 2002 I put the "Rhodesian Ridgeback Pedigree Search“ database online, which has enabled me to establish numerous contacts with Ridgeback breeders, scientists and genetics worldwide. A fact that has helped me enormously on my way.

In March 2004, just a year after I joined Club ELSA, I was appointed breeding accountant by the board and a year later, in April 2005, breeding manager. I often had discussions with our first chairman about the distribution of the DS in our breed, the connection between DS and Ridge and the agony breeding report in which the Rhodesian Ridgeback is listed due to the DS. Even then there were efforts to get in touch with the VDH regarding a breeding program - but the time was probably not yet ready for it.

In the same year, Dr. Mark Neff (University of California at Davis) and Nicolette Salmon-Hillbertz (Swedish University of Agricultural Sciences Uppsala) contacted me. Dr. Mark Neff dealt with the inheritance of the Ridge. DNA classification was performed using cellular material from swap samples from dogs that were collected worldwide and sent to California. Many of our breeders took part in it at this time. At that time there was an unplanned litter of two ridgeless Ridgebacks from a Club ELSA breeder - all 11 puppies were (as expected) ridgeless and I have sent swap samples of the puppies to the USA. Unfortunately this study obviously did not get any further because it was discontinued after a few years without producing any significant results.

Nicolette Salmon-Hillbertz and her team, among others, dealt with the Dermoid Sinus in connection with the Ridge, also Kerstin Lindblad-Toh (Broad Institute USA and Uppsala University Sweden). They found out, that the Ridge occurs when dogs have multiple copies of a region of the genome that contains genes with certain growth factors (FGF). The mutation of this gene leads to a defect in the system of planar cell polarity.

This system is required for the normal alignment of the hair follicles as well as for the neural tube closure (if this is not done, the Dermoid Sinus will develop). They also found out, that the mutation responsible for the Ridge dominated and that dogs with two copies of the mutation were more susceptible to Dermoid Sinus than dogs with only one copy.

The breeding program of Club ELSA/VDH

The results of the studies in Sweden were published in 2007 and presented by Prof. Tosso Leeb (Institute of Genetics at the University of Bern) on the occasion of the meeting of the responsible breeders of the VDH in November 2007, in which I took part.

At that time I was already the first chairman of the Club ELSA and took the opportunity to speak personally with the speaker and the chair of the scientific advisory board of the VDH and the VDH breeding commission.

A few days later I made an initial request and stayed in constant contact with the responsible people of the VDH. On February 8th, 2008 I finally submitted an official application for a test mating breeding program to the VDH on behalf of the board of the Club ELSA.

Already 2 months later, on April 25th, 2008, we received a letter from the chair of the scientific advisory board that the VDH agreed to the breeding attempt to avoid the Dermoid Sinus. The way was clear to put our theory into practice.

Already in October 2008 the first litter with a ridgeless female and a ridged male was born in Club ELSA - all 9 puppies of this litter had a Ridge and NO Dermoid Sinus.

In 2014 I decided to take a ridgeless bitch from a litter of my offspring Thuraia Etana Kianga, who was the foundation bitch in Switzerland at the Bussmann family in Kennel KIANGA. I made this decision very deliberately, because I was always convinced that the use of ridgeless dogs in Rhodesian Ridgeback breeding makes perfect sense. Ginny, the ridgeless bitch, was in my opinion the best bitch in the litter and therefore it was clear to me - she is coming to us. She had her first litter in 2018 - as expected, none of the puppies had a DS.

Ginny’s ridgeless sister Bashira also came to Germany to breeder in our Club and had a litter in 2017 - none of the puppies had a DS. In the same year there was another litter at Club ELSA with a ridgeless bitch - there was no puppy with DS here either, although all puppie had a ridge.

A worldwide theme

In the next few years a lot also happened abroad – amongst others Ann Chamberlain, long-time Rhodesian Ridgebacks breeder and author of numerous books, had a litter with her ridgeless female. Again, all puppies had a Ridge and there was no Dermoid Sinus. She also wrote an article The big genetics experiment. Her final sentence in the article: “Don’t throw out the baby with the bathwater!  We may need those ridgeless dogs down the line!”

I myself wrote countless articles about breeding with ridgeless Ridgebacks, the genetic background and the intension behind it, and little by little the topic became interesting for more and more scientists and geneticists.

In 2017 the FCI even considered creating its own variety for ridgeless Ridgebacks, which of course can be paired with ridge-carrying Ridgebacks ( FCI proposal for ridgeless varian ). To what extent this idea is being pursued is currently unknown.

The topic was hotly debated in the Ridgeback world, especially during the Rhodesian Ridgeback Worldcongress (RRWC) in Ireland in 2008 and Sweden in 2016.

On the occasion of the RRWC in Sweden 2016, the following was decided at the end of the congress:
"The 2016 Rhodesian Ridgeback World Congress recognizes that breeders are autonomous and are the best arbiters of what should happen in their whelping boxes. To that end, the 2016 RRWC strongly encourages breed clubs to avoid punitive language in their codes of ethics or other official documents regarding the breeding of healthy Rhodesian Ridgebacks with only cosmetic faults, and strongly encourages openness and honesty between breeders."

Unfortunately this was from many people, especially in Germany, not heard or they didn't want to hear it.

The genetics behind the Ridge

Ridge inheritance is a simple, recessive inheritance. Here the dominant gene R stands for "Ridge" and the recessive gene r for "ridgeless".

So there are 3 basic genetic types:

R/R - with Ridge and two dominant genes
R/r - with Ridge but only one dominant gene
r/r - ridgeless

Depending on the mating we get the following result:

R/R x R/R: all descendants R/R and with Ridge
R/R x R/r: 50% R/R 50% R/r - all with Ridge
R/R x r/ : 100% R/r - all with ridge
R/r x R/r: 25% R/R 50% R/r (75% with Ridge) 25% r/r without Ridge *
R / r x r / r: 50% R/r with Ridge and 50% r/r without Ridge *
r / r x r / r: all descendants r/r and without Ridge
* statistical value

Since a few years now there is a genetic test for the Ridge, developed by Miroslav Hornak at the "Genetic and Reproduction Veterinary Research Institute Brno" ( Gene Test ). According to this test, the majority of the puppies tested with Ridge and DS are homozygous for the Ridge, which confirms the scientific knowledge of the past years.

This test is now also being questioned by many breeders, because in extremely rare cases (previously in 2 litters) ridgeless puppies with the gene status R/r (the large R stands for the ridge, the small r for ridgeless – usually this dogs have a Ridge). But obviously it is also possible in very rare cases that the Ridge is not pronounced.

The litter with my Ginny in 2018 was the last litter in the VDH breeding program to combat the DS, because the VDH stopped the program in summer 2018 on the grounds that it is simply no longer necessary because we now we know, that homozygous Ridge carriers (gene status R/R) have an increased risk for the Dermoid Sinus.

The VDH (Germanl Kennel Club) decision

In April 2019, the VDH finally informed the Rhodesian Ridgeback breeding clubs that the use of ridgeless Ridgebacks in VDH breeding is generally permitted. (Note: in some Scandinavian countries, the Kennel Clubs allowed this already a few years ago and meanwhile some breeders have ridgeless females who will be bred).

In Germany this was the starting signal for a shit storm against the breeders with ridgeless bitches and even their offspring.

It's so easy to stigmatize an optical trait and stir up fear that we would "lose" the ridge! This is by no means the case.

Even if some do not want it to be true: offspring of a mating of a ridge-carrying Ridgeback and a ridgeless Ridgeback that carry a Ridge (gene status: R/r) do not carry more ridgelessness in themselves as descendants of two ridge-carrying Ridgebacks, who are heterozygous ( are mixed) for the Ridge gene (gene status also R/r). It is a simple, recessive inheritance and the Ridge inheritance is simple Mendel genetics.

The fact that it is now known that homozygous Ridgebacks for the Ridge have an increased risk of carrying the genetic defect Dermoid Sinus and, when paired, inherited, and that geneticists and biologists worldwide advocate the use of ridgeless Ridgebacks is simply ignored. It is much more important to breed ONLY with dogs that have a Ridge and you continue to take the risk of Dermoid Sinus and the fact that these puppies need surgery to survive! Instead, all means are being used to fight against the use of ridgeless Ridgebacks, for whatever reason.

Because of to the Dermoid Sinus (DS) the Rhodesian Ridgeback is listed on the “Agony breeding report” (Report about the prevention of breeding causing pain, suffering or harm) in Germany.

Excerpt from the quality breeding report of the Federal Ministry of Food, Agriculture and Forestry (report on the interpretation of § 11b of the Animal Welfare Act) from 1999:

Skin indentations on the back, which can extend into the spinal canal.
Rhodesian Ridgeback

The Dermoid Cysts appear on the back in front of and behind the "Ridge" (hairline with opposite growth). They develop embryonic from an imperfect or incomplete separation of skin and spinal cord. If the connection to the spinal canal and spinal cord remains, this can lead to hindquarters paralysis and hyperesthesia (hypersensitivity), infections also cause changes (meningitis, myelitis).

Breeding ban for animals afflicted with dermoid cysts because pain and suffering can be expected in the offspring.

The only problem is, that these dogs have been excluded from breeding for many years and the percentage of puppies with DS has not changed. We always have had the same number of puppies that need surgery over the years. So that didn't help us either.

A gene test for the dermoid sinus is currently not available - despite years of intensive research.

The Animal Welfare Act and the European Convention for the Protection of Pets stipulates conditions for the protection of pets. Amongst other things it is written here:
"Defect genes and genetically determined anomalies must be taken into account in breeding (selection) in such a way that if possible there are no offspring (with this traits) that are associated with pain, suffering or damage."

A German veterinarian proudly announced last year that he had operated on his 1000th Dermoid Sinus (and he is by far not the only veterinarian in Germany to makes this surgery)! But ... we don't have a DS problem in the breed? Who can believe that when such facts are published?

Our breed is not yet 100 years old, but we already have a massively narrowed genetic bottleneck that we willfully pull closer and closer. Even though we have alternatives.

As breeders, we sit in the welping box and the first characteristic after we choose our future breeding dogs is the perfect Ridge. Of course, the dogs should not have too much white, too much black hair, a.s.o. because many judges do not like that at the exhibitions.

Character and health play a parent role for me as a breeder, not a dog's cosmetics. And if, as planned by the KUSA (the standard of the Ridgeback was "revised" there), it would be allowed in future to breed with aggressive and overly shy dogs, this definitely cannot be in the sense of breeding. Not a great development for a dog breed that was still on the fighting dog list in Germany a few years ago and only came off the list through consistent breeding with temperament tested dogs.

Nobody is forced to integrate ridgeless ridgebacks into their breeding, but every breeder should be allowed to decide for themselves. It is perfectly clear that the use of ridgeless ridgebacks will certainly not be the rule but rather the exception, but it should be up to the breeder without being pilloried.

The FCI (Federation Cynologique Internationale), the international organization

The introduction to the FCI breeding strategies includes the following:

„The goal in dog breeding is functionally healthy dogs with a construction and mentality typical to the breed, dogs that can live a long and happy life for the benefit and pleasure of the owner and the society as well as the dog itself. Breeding should be carried out in such a manner that it promotes the health and well-being of the progeny, as well as the welfare of the bitch. Knowledge, honesty and cooperation, both on national and international level, is basic in healthy dog breeding. Breeders should be encouraged to emphasize the importance of the combination of dogs as well as selection of the individual dog to be used for breeding. The FCI members and contract partners should conduct education programmes for breeders, preferably on an annual basis. Education of breeders is to be recommended rather than strict breeding regulations and stringent demands in breeding programmes, which can easily result in reduced genetic diversity in the breed as well as exclusion of excellent breed representatives and reduced cooperation with conscientious breeders. Breeders and breed clubs should be encouraged to cooperate with scientists in genetic health issues, to prevent combination of dogs from lines that will result in unhealthy offspring. Any dog used for breeding or screened for inherited diseases, must have identification (chip or tattoo). The breeders should keep the breed standard as the guideline for the breed specific features; any exaggerations should be avoided."

The FCI Breeding Committee already made the following recommendation to the Central Committee in 2012:

"It is genetically impossible to breed naked dogs without getting the hairy variation, or harlequin without getting the merle colour – or healthy rigdebacks without ridgeless dogs being born. Therefore coat, colours and anatomical features that genetically must appear in a breed in order to breed what is now preferred in the standard (i.e hairless, ridgebacks), should be equally accepted in the standards; the standards must be changed to achieve this."

There is nothing to add.

Monika Pehr
February 2020