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The Effects of Inbreeding in Golden Retrievers

The Effects of Inbreeding in Golden Retrievers

Inbreeding in Golden Retrievers   /   Aug 15th, 2018   /   0 COMMENTS   /  A+ | a-
The general rule for responsible breeders is that inbreeding should be avoided. Inbreeding is when a male or female adult dog is bred with a relative of that dog (e.g., brother, sister, parent, grandparent, cousin, etc.). However, if you go back far enough in a dog's family tree, virtually every pure-bred dog will have traces of inbreeding, primarily because of the age of our country and the population of pure breeds in this country. Keep in mind the American Kennel Club, which maintains the largest registry of pure-bred pedigrees in the U.S. was only formed in 1884, and the Kennel Club of England (the first and oldest pure-bred dog registry in the world) was started in 1873. The Golden Retriever breed itself has only been around for a little more than a 150 years, originating in the highlands of Scotland. If you think about a pure-breed’s origins, in order to stay within that breed and not cross into another breed, inbreeding was necessary. So, the further you go back in time in this country and throughout the world for the Golden Retriever, the sheer numbers of the breed become fewer and fewer. Thus, inbreeding was inevitable and certainly more prevalent in the past than it is today.

But there are also some justifiable reasons for inbreeding: when certain traits such as color, physique, or temperament are sought after in certain dogs, some breeders will use a related male and female with those desirable traits to increase the chances of those traits in the offspring. Traditionally in the past, Golden Retriever breeders fairly commonly used grandfather/grand-daughter matings (and often times even closer related) to emphasize certain traits and make them dominant in subsequent generations. In reality, inbreeding is precisely what occurs in the origins of any pure-bred dog. Not as much inbreeding occurs today, but it does occur. So, what are the problems with inbreeding in light of the fact that it was being done more commonly and purposely in the past?  There are two primary problems:

 
  1. Ignoring environmental causes for the moment, no Golden Retriever is 100% risk free and problem free of disease throughout its life. There will always be some weaker traits that can be more susceptible to disease, and may develop into health issues in a Golden Retriever’s lifespan. It’s just the nature of anatomy. So, if a potentially unhealthy trait of some kind is in a particular dog’s genes, and it is mated with a close relative, then the related dog can also have a high probability of having the same unhealthy trait. When mated, that unhealthy trait would be potentially emphasized or inherited in the offspring. This can cause a rapid buildup of diseased or mutated genes in the lineage of a Golden Retriever; and
  2. Even if a Golden Retriever is free from any serious genetic disorders, inbreeding can also result in breeding problems of future litters produced by the offspring such as less vigorous or viable puppies in those future litters, a weakened immune system in those future pups, and a shorter lifespan. These types of problems are known as “inbreeding depression”.

However with those two points being made, inbreeding should not be completely dismissed and characterized overall as a bad thing, because in genetics, nothing is concrete because of all the variables. There are some very good examples in the dog breeding world of highly inbred lineages that appear to be very healthy, very viable, and very fertile, litter after litter. Conversely, if there is a low degree of inbreeding in the lineage of a dog, it does not guarantee that dog’s offspring will be free from genetic disorders or health issues. But, if there is a high degree of inbreeding, it should cause some concern because it may result in a higher probability of health issues in that dog’s offspring.

Okay, if there is always some degree of inbreeding found in the family tree of a Golden Retriever, how much is too much and how much is acceptable? In England, where the dog population is smaller than it is in the U.S., and inbreeding is far more likely, veterinary geneticists have developed a measurement of the degree of inbreeding called the, “Coefficient of Inbreeding” (or COI). They have also established guidelines for the amount of inbreeding that is considered healthy and acceptable in good breeding practices. The COI can be analyzed for any dog if the pedigree of that dog is known for the recommended minimum of at least five generations.

We think that a responsible breeder should consider the pedigrees of the dogs they use in their breeding program to avoid genetic health issues and the possibility of premature death caused from a build-up of diseased genes and genetic disorders (inbreeding depression). Currently, the best way that responsible breeders can prevent or minimize this as much as possible, is to take a very detailed look at the Coefficient of Inbreeding, COI, which is expressed as a percentage and is sometimes referred to as IC, WIC, Fx, or F in various studies over the years. The lower the COI percentage, the less chance of “inbreeding depression”, according to the geneticists who have studied this topic for decades.

In addition, veterinary geneticists have been discovering mutated gene structures of various diseases in the DNA of dogs which can be identified in saliva and/or blood samples from Goldens. The presence of a mutated gene means that there is an increased chance of passing the disease or disorder to a dog's offspring, depending on whether both parents have the mutated gene, and whether or not both grandparents had the mutated gene. If the gene trait is a dominant trait, this also increases the chances of disease in the dog's offspring if allowed to breed. This is in contrast to a recessive gene trait which is not passed on to offspring unless both parents have the same mutated or weakened gene structure that is more proned to a certain disease. DNA sequencing and analysys can reveal quite a bit of this information about the parentage of a dog. It can also reveal whether a dog will actually be at risk of acquiring a specific disease at some point in its life, or just simply be a carrier of the genetic mutation, but that dog itself is not at risk of acquiring the disease. In this latter case, a dog that is not at risk of acquiring a disease from a mutated gene structure can still pass the mutated or weakened gene structure on to its offspring if the dog is allowed to breed.

Therefore, genetics play a very important role in the developing a viable and healthy breeding program. Defective genetics are the enemy of inbreeding Golden Retrievers and this is why we feel that taking a very close look at the family tree of Golden Retrievers is imperative. DNA testing can be very expensive but costs and the efficiency of testing has improved over the years and are expected to continue that direction. If inbreeding exists in the not to distant past of a Golden Retriever's family tree, (which is also revealed by a high COI percentage), then genetic testing is imperative to rule out the increased probabilities of disease in the offspring of a dog.


To determine the COI percentage, the ancestral lineage of the parents need to be known for at least five generations. Then, these have to be evaluated by a calculation using a rather complicated formula, which if you think about it can become pretty complex considering there are 31 males and 31 females in a five generation pedigree. So then, to evaluate the suitability of a particular male and female for breeding purposes, there are 62 dogs that have to be included in the analysis! This requires something like a spreadsheet to do this complicated evaluation of the COI percentage. The following will help you understand the COI percentage of two dogs that are bred and are closely related. Theses COI percentages occur after only one generation of puppies are considered. The percentages become lower as more unrelated generations are included in the COI analysis, or become higher percentages if inbreeding continues between close relatives:

 
  • If a parent is mated with one of its children, the COI percentage is:  25%
  • If a brother and sister are mated, the COI percentage is: 25%
  • A grandparent mated with a grandchild results in:  12.5%
  • Children with one only common parent (half siblings):  12.5%
  • A great grandparent mated with a great grandchild:  6.25%
  • First cousins who mate:  6.25%
So as you can see, the more distant the relative, the lower becomes the COI percentage. The lower the COI percentage, the less chance of inbreeding depression. Here are some additional points to consider:
  • The ideal COI for five generations would be 0% (this is becoming more and more uncommon in Golden Retrievers because many of today's newest breeders do not put much thought into the lineage or inbreeding of their breeding dogs).
  • Experts in the field of genetics recommended that the COI for five generations should not be more than around 6% to reduce the chances of “inbreeding depression” (this is equivalent to mating first cousins, or great grandparents with great grandchildren).
  • We at Golden PuppiesTM think 6% is way too high unless a very thorough health screen in all possible areas of the male and female Goldens are obtained, and parents on both sides of the Goldens are known to have had an excellent health history. A COI of 6% is not entirely uncommon among some breeding professionals, and is more common with imported dogs.
  • The preferred COI for five generations according to some experts should be lower than 3% to avoid or minimize “inbreeding depression”.  At Golden PuppiesTM, we agree that having a COI as low as possible should be the goal.
There is a caveat with COI because it can sometimes be a little misleading and show a percentage of nearly 0% if a brother and sister are mated but the five generations before them are completely unrelated. To overcome this potentially misleading problem, another evaluation called “Ancestor Loss Coefficient”, or AVK should also be evaluated from the pedigrees of the parents. According to experts, the AVK should be higher than 85% to avoid “inbreeding depression” and promote good genetic health. The higher the AVK percentage, the better chance of avoiding “inbreeding depression”. We feel strongly that both COI and AVK should be considered before breeding a male and female Golden Retriever in our breeding program.

If you want to know more about this subject, click here for an excellent article designed for the lay person to understand. In addition, a teaching video on calculating the Coefficient of Inbreeding can be viewed here. And finally, we have determined the COI and AVK for litters produced by all of the dogs in our
Golden PuppiesTM breeding program. First, we have listed the COI and AVK of each of our adult breeding dogs in the first table below. Then we have listed the COI and AVK for the offspring produced by the adult pairings that we have selected in our four different litter colors.  They are as follows:

 
 
  Results of Inbreeding Analysis


Our Individual Adult Dogs:
COI
(experts recommend
less than 3.0%)
AVK
(experts recommend
greater than 85%)
Huck (white cream) COI = 0.0% AVK = 90%
Duchess (white cream) COI = 0.0% AVK = 90%
Duke (white cream) COI = 0.0% AVK = 90%
Esmae (light blonde)* COI = 0.0% AVK = 95%
Arianna (light blonde) COI = 0.0% AVK = 90%
Oliver (light blonde) COI = 0.0% AVK = 95%
Alexis (light blonde) COI = 0.0% AVK = 97%
Aramis (caramel color) COI = 0.0% AVK = 97%
Scarlett (caramel color) COI = 0.0% AVK = 97%
Rhett (auburn) COI = 0.2% AVK = 90%
Willow (auburn) COI = 0.2% AVK = 90%
Beau (auburn) COI = 0.2% AVK = 90%


 
  Results of Inbreeding Analysis


Litter Color Pairings:
COI
(experts recommend
less than 3.0%)
AVK
(experts recommend
greater than 85%)
Huck and Duchess (our current white cream litter pairing)* COI = 0.0% AVK = 90%
Duke and Esmae (future light blonde litter pairing) COI = 0.0% AVK = 90%
Duke and Arianna (future light blonde litter pairing) COI = 0.0% AVK = 90%
Huck and Arianna (future light blonde litter pairing) COI = 0.0% AVK = 90%
Oliver and Arianna (our current light blonde litter pairing) COI = 0.0% AVK = 90%
Oliver and Lexi (our previous light blonde litter pairing)* COI = 0.0% AVK = 95%
Rhett and Scarlett (our previous caramel litter pairing)* COI = 0.0% AVK = 97%
Aramis and Scarlett (our current caramel litter pairing) COI = 0.0% AVK = 97%
Rhett and Willow (our current auburn litter pairing) COI = 0.2% AVK = 90%
Beau and Willow (our previous auburn litter pairing)* COI = 0.2% AVK = 90%

We hope this article is helpful to those who are concerned about inbreeding, and perhaps to those who have experienced health problems or loss of their Golden Retriever and suspect it may have been due to a high percentage of inbreeding. If this is something you want to explore a little more, give us a call and perhaps we can help you determine if inbreeding was potentially the cause of your loss. Thank you for considering Emery-n-Denise's Golden PuppiesTM

We are exclusively a Golden Retriever Breeder of AKC pure bred Golden Retrievers and we have Golden Retriever Puppies for sale in Virginia and Washington.
 
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