Why is it important to have a low inbreeding rate and to check pedigrees and breeding data? For healthy dogs and a good future for the breed.
Below we will highlight four genetic concepts that we will explain a little and that are considered important for responsible breeding.
The reason these things are considered so important is, among other things, the following, according to those knowledgeable in genetics.
1. Increased frequency of recessive homozygotes relative to heterozygotes causes reduction in fitness, growth, fecundity and more, which can lead to inbreeding depression.
2. Inbreeding causes random loss of genetic predisposition.
3. Reduced genetic variation within inbred lines limits genetic diversity and results in reduced breeding progress in the long run.
It can be summarized as follows:
High degree of inbreeding can lead to diseases = poorer health. Loss of genetic material that can lead to the loss of the originally intended characteristics of the breed. Further impair the possibility of having puppies and also lead to smaller litters of puppies. As well as future difficulties in finding suitable breeding combinations. Simply a healthy future breed.
Our goals in these matters
In our own breeding, we always strive to have as low an inbreeding rate as possible. Preferably 0.0. As well as as wide a range of kinship as possible. A high value of AVK. But, of course, this must take place as a whole, where other important things are good health, a healthy mentality and a (beautiful) race-typical exterior.
4 genetic concepts that are important as well as DNA tests.
IC - Inbreeding Coefficient
Can theoretically range from 0 to 100%, and shows the degree of relationship between the parents and the relationship between previous dogs in the lines. A high degree of inbreeding results in a higher duplication of genes, which can be both good and bad. More about this further down under "Which limits..."
AVK - AVK is from German AhnenVerlust-Koeffizient, or in English ancestor loss coefficien. Shows how many different parents there are in the pedigree in relation to how many would be possible. If, for example, the entire pedigree would consist of different parents, the number would be 100%, which results in maximum genetic breadth. If there are parents in several places in the pedigree, this number decreases at the same time as the genetic width decreases. So this number should be as close to 100% as possible. It is believed that this number must be over 85 to mate.
RC – Relationship Coefficient. RC shows the relationship between the previous lines of both parents. Just over half of all hereditary defects are caused by hidden (recessive) genes. For the continued health of a breed, it is therefore important to consider in each pairing the degree of relationship that the relationship coefficient (RC) represents in the parent dogs to avoid a doubling of possible defects in the alleles. (See also under DNA tests below.)
MK – Mean Kinship Coefficient.MK describes the kinship of the currently entire population. Average relatedness is a measure of an animal's importance. Animals with low average relatedness are genetically important. Animals with high average relatedness should be used less (or not at all). Average relatedness is calculated by the animal's relatedness to the entire current population (including itself). Therefore, average relatedness per animal is relative to the current population. Which means that the relatedness of a specific animal can change over time as a population changes. For example, the average relatedness will increase each time an animal produces offspring.
Another possibility to make sure that the inheritance of some autosomal recessive inherited diseases cannot happen, is to do a DNA test where certain genes are tested. If one of the dogs is tested and free of these genes, the puppies cannot get sick with this disease, as it is required that both parents must be carriers for the puppy to develop this disease. Samba is DNA tested on 210 genes, and free on all. Which means that regardless of breeding combinations, the puppies cannot develop this type of genetically inherited diseases.
What limits should be considered when it comes to IC and AVK?
As a general rule of thumb, IC should be below 3% and AVK should be above 85% to make a match. Another measure of IC is that 2.5% over five generations is considered an acceptable level over time. Which then means that above 2.5 you get a deterioration of the total population and below 2.5 you improve the total population in the long run. If everyone were to breed at over 2.5, the breed would develop negatively over time. Which in turn leads to the fact that if some breeding takes place with combinations that give more than 2.5, others must breed just as much less to prevent a total deterioration of the breed. In this matter, everyone must try to help each other and take responsibility for a future healthy race.
Another number that is also usually stated, in some of these databases, is how much of the pedigree is complete. The more complete the pedigree, the more reliable the calculations. The lack of individuals in the pedigrees mainly applies further back in time. With each new generation, the pedigrees become more and more reliable.
This is what it looks like for our upcoming litter between Samba and Laban.
Regarding our upcoming litter with Samba and Laban, the inbreeding rate is 0.0 over 5 generations according to SKK's breeding data, which we often refer to here in Sweden. And if we look at Pyreneisk Mastiff Pedigreedatabaseonline.com, the inbreeding rate is 0.2 depending on that this database is more complete than the one SKK has on these lines in generation 4 and 5 and further back in time, which largely contains dogs from outside our Nordic countries. And their AVK value is a whopping 95%.
The values of Samba and Laban and their puppies, in terms of IC and AVK
Samba and Laban in their combination have very good values for these two figures according to established criteria. For a future healthy breed, we believe that these values are very important. We will work to keep it that way. Should we not be able to, we will refrain from it. In our opinion, possible exhibition successes are not a reason to depart from these very important principles.
The day we bought in Samba and Laban, we planned for it to be like that. But we can't deny that we fell for them when we saw them as little puppies, and we still do, because they were adorable, nice, cute, and pretty. Corresponding thoughts are of course also with Luna, provided that everything else is also good with her.
Here are the numbers for Samba and Laban and the upcoming litter of puppies.
Samba has in its own pedigree the following value of IC and AVK seen over 5 generations:
IC 0.2% and AVK 88.7%
Laban has in his own pedigree the following values over 5 generations:
IC 0.29% and AVK 92.9%
Their puppies will have the following value over 5 generations:
IC 0.2% and CI 95%
The result is a low 0.2% on IC. And the result has improved at AVK.
However, we would like to add that there are a large number of other things that must be taken into account in your breeding. But these lines start from the genetic perspective, as a very basic and important part.
But pedigrees and breeding data can provide much more important information. How possibly over bred some dogs are. Which dogs are included backwards in view of any known knowledge about these dogs' behavior, diseases, lifespan, etc. How often litter siblings are also included in the various lines. What is the status of the litter siblings etc.
The degree of inbreeding between the two parents is of course important. But also how has the inbreeding looked in their previous generations in the respective parent's lines. Has this perhaps possibly affected loss of genetic breadth earlier in the lines.
Genetics is an important part of the breeding work in combination with a number of other important issues. Everything must be weighed together.
Breeding data can be found, among other things, in the following databases. Where you can see different pedigrees and find valuable information.
The Swedish Kennel Club's breeding data.
Finnish Kennel Club breeding data.
PeedigreDatabaseOnline.com. Under the “trial breeding” tab.