by Steve1972 on 03 July 2023 - 13:07
I own a female with Kronos Von Nürburgring in her second line. Based on what I’ve been reading, for line breeding to be effective it needs to be closer than what most people practice.
What I am seeking opinion on is wether or not to linebreed on Kronos. And would it be too risky to do a 2-2, or should I try a 2-3?
Also, while scrolling the classifieds on PDB I rarely come across pups or dogs with Kronos in their pedigree. I find some occasionally but not very often. Usually these top VA dogs sire a tremendous amount of offspring. Does anyone know why this is not the case with Kronos?
Does anyone know of where I might be able to find a stud dog with Kronos in the 2nd or 3rd line?
Below is a link to my Gingers PDB pedigree if anyone would like to look.
Thanks in advance.
by Dragan Stojiljkovic on 05 July 2023 - 05:07
by Gh Westline Kennel on 16 July 2023 - 06:07
Inbreeding in Dogs occurs when closely related dogs mate, sometimes over many generations. For example, a father to a daughter, a brother to a sister, a half-brother to a half-sister, a mother to a son, and so on.
The ultimate goal of inbreeding is to improve and preserve desired qualities by increasing homozygosity (the degree of genetic similarity between two individuals) in the dog’s genetic pool.
Inbreeding is a process in which the animal’s traits and qualities, both good and harmful, become more pronounced with each successive generation.
The ultimate purpose of inbreeding is to improve and preserve the features desired by the breeder by boosting homozygosity in the dog’s genetic pool.
by alexnds05 on 17 July 2023 - 13:07
Steve, To answer your question, a 2-2 breeding is a breeding of half siblings. This is not line breeding, but inbreeding. A breeding of 2-3 (Uncle to Niece) or 3-2 (Aunt to Nephew) is the closest line breeding you can do. The 2-3 or 3-2 is no longer allowed in Germany but it is allowed in the USA. Your goal is to create a Pre-potent animal: an animal that will consistently pass along his characteristics into the future, despite living in the past.
To do so, the offspring he begets need to have a high percentage of his genes, or be homogeneous gene pairs. The more you go to the future, the more diluted his blood becomes. Your goal in creating a line is to concentrate his genes in such a way, that despite the passage of time, his influece is seen several generations later.
Sewall Wright came up with an equation in 1922 on this subject. Hardiman came up with an equation in the year 2000. The PDB shows results for both. I believe Hardmiman's equation is more accurage.
There is something called the inbreeding coefficient, which is what percentage of the genes are passed on from the common ancestor and coefficient of inbreeding (COI) , which is what portion of those genes are homogeneous. In order to create "pre-potency", or an animal that will pass himself forward in time, no matter what he or she is bred to, you need to do what is called "tight" line breeding. Loose line breeding, such as 3-4, or 4-4, 5-5, is still linebreeding, but it is not efficient in creating a prepotent animal. In other words, if you breed a pre-potent dog as the sire, he contributes 50% of the genes to the offspring and his female partner contributes the other 50% as well. But because he is homogeneous for alot of those genes, he will pass them 100% of the time, and therefore, his 50% will be "stronger" in the influencing the characteristics of the offspring than his partner. So the pups will come out more like the dad and less like the mom, because the dad is "pre-potent". Let's clear this up. People confuse line breeding and inbreeding. The poster above is confusing the two. Father-to-daugther (1-2) or mother-to- son (2-1) is inbreeding. Grandfather-to-grand-daugther (1-3) or Grandmother-to-grandson (3-1) is inbreeding. Full siblings and half siblings (2-2) is inbreeding. First cousins (3-3) is linebreeding. Second cousins (4-4) is line breeding and Third Cousins (5-5) is linebreeding as well. Uncle to Niece (Lloyd Bracket's method) , or 2-3 is also linebreeding.
Line breeding is much less likely to cause harm than inbreeding. Breeders cultivate lines because they love aspects of those dogs. A big part of breeding purebred dogs is breeding for consistency in temperament, type, drive etc. So how does linebreeding fit in to this? Linebreeding can quickly and easily set type within a line, which will create more consistent offspring in the above mentioned traits. It can also mean high levels of inbreeding, but not necessarily. So the COI is a measurement of how much close is too close. Where do you do it and when you should stop?
The goal is to get below 25% COI (which is parent to offspring or full sibings) or or more realistically below 12.5% , which is half sibling or grandparent-to-grandchild,. So at any number below 12.5% COI is acceptable. For example, uncle to niece has a Hardiman Coefficient at 9.63% which is below 12.5%. Common grand-parent (3-3) is a 6.25%, which again, is below 12.5%. So any number below 12.5% is the goal. Now, you can also accomplish double first cousins. In other words, 4-4, 4-4 is same thing as a 3-3. In other words, you can repeat the same ancestor several times in the past, and it has more effect than repeating him only once on both sides.
Why line breed vs inbreed? That old mantra is true for the very reason you need to understand COI. Offspring can really vary from one another and a couple generations away from an individual, one descendant can be very different from its ancestor, while another descendant will be much closer related. This could render one linebreeding genetically safer than another by reducing risk of deleterious mutations expressing in the resultant offspring.
I explain the methods on this video: click to view
The goal is to line breed to create a "line" and then outcross to remove detrimintal effects of doubling up on recessive and dominant genes. Once you out cross, the next generation, you can line breed again! In other words, it's all about balancing risks and rewards to "stamp type" while at same time avoiding genetic bottlecks.