Can You Inbred Dogs? The Underlying Truth Behind Inbreeding!

When I first got involved with dogs, I remember chasing my first pedigree and being surprised to see that there were inbred dogs on the pedigree. If you aren't sure what this is, it's when you look at the family tree of a dog. While it is common to see similar dogs in pedigree with purebred dogs, many new to the purebred dog world are surprised when they realize that inbreeding dogs is a common practice.

But is it a safe practice or one that you should avoid if you can? The answer might be surprising and that is why we are going to look at the pros and cons of inbreeding dogs.

What is Inbreeding?

Inbreeding dogs is when you breed closely related dogs together.

As you may know, inbreeding is when relatives produce offspring. But let's look at it in depth when it comes to dog breeding. First, we should realize that there are two terms that are often used in dog breeding. These are inbreeding and linebreeding. But what is the difference?

It should be noted that both are a form of inbreeding. However, they are slightly different.

  • Linebreeding: This is when a dog is seen more than once in a pedigree. So a dog might be your pup's sire and the dam's grand sire. Most breeders consider linebreeding as a better option than close inbreeding but we will get into that in a different article.
  • Close Inbreeding: As mentioned, both of these practices are inbreeding, however, close inbreeding is when the dogs are closely related. For instance, inbreeding includes brother to sister, mother to son and father to daughter.

For the purpose of this article, we are going to be looking at the pros and cons of close inbreeding.

Why Breeders Inbreed?

Breeders use inbreeding dogs to set desired breed traits.

When inbreeding was first explained to me, I was told one simple sentence, "Inbreeding is to lock in a trait." What this means is that if you have a dog with a desirable trait, such as a perfect otter tail in a Labrador Retriever, you breed that dog with his daughter, who also has a perfect otter tail.

(Note: an otter tail is a desired tail in a Labrador Retriever and has a thick base that is round and tapers to the end.)

The belief is that by doing this, you are going to lock in that perfect otter tail so puppies born from them are more likely to both have and continue to produce an otter tail in their offspring.

And while it seems like a strange thought, it is actually one that works. In fact, without inbreeding, we would not have the breeds we have today. Puppies were produced having a desired trait and breeders would use inbreeding to ensure that it became a dominant trait in the dog...such as the otter tail in labs.

However, with the good, also comes the bad and it is very important for breeders to be aware of both if they plan to add inbreeding to their breeding program.

Understanding Coefficiencies with Inbreeding Dogs

COI is a way to calculate how inbred a dog is.

Before we look at pros and cons, I want to make a small point about coefficiencies. First, a coefficiency, or Coefficient of Inbreeding (COI) is a measure of how closely related a dog's pedigree is...other words, how inbred that dog is. There is a lot to get into with COI, but the general rule of thumb is that the lower a COI is, the less inbreeding has been done.

The higher the COI, the greater the risk of having health problems and the many cons that are seen with inbreeding. Therefore, a low COI is better than high COI.

In our models, you should expect the following COI's.

  • 100% Unrelated Dogs: 0% COI
  • Full Brother to Full Sister: 25% COI
  • Half Brother to Half Sister: 12.5% COI
  • Parent to Offspring: 50% COI
  • Grandfather to granddaughter: 12.5% COI
  • First cousin to first cousin: 6.25% COI
  • Great grandfather to great granddaughter: 6.25%

Note: Grandson to grandmother/ great grandson to great grandmother are rarer in occurance.

Pros of Inbreeding Dogs

There are some pros to inbreeding, which is why it is still used.

Although I have outlined one of the main benefits of inbreeding in the section above, there are a few other pros when it comes to inbreeding dogs. These include:

  • Locking in a desired trait.
  • Using a dog that compliments your female.
  • Having more predictability in regards to temperament and looks.
  • Enables you to fix a bad trait in the dog.

Obviously, if your dogs share the same genetics, they will have many of the same characteristics that you want in your puppies. Breeding them together will help ensure that you produce a predictable litter when it comes to traits.

Cons of Inbreeding Dogs

A major con of inbreeding dogs is inbreeding fatigue.

Now that we've looked at the pros, we should mention that their are cons involved. These are:

  • Locking in an undesired trait. While many breed for a desired trait, it is quite possible to lock in an undesired trait. Once locked in, it makes it harder to breed that trait out of your dogs.
  • Fertility issues. This is very common and can be caused by inbreeding fatigue. Fertility goes down for both male and female with smaller litters and more difficulty getting pregnant.
  • Increase in birth defects. Inbreeding can lead to more birth defects in puppies, which can also result in higher puppy mortality rates in your litters.
  • Decrease in size. This varies from breed to breed but inbreeding is often linked to smaller dogs when they reach adulthood.
  • Genetic diseases. It is more likely to see an inherited disease in inbred puppies than in those that are not.

And finally, the more a dog's pedigree is inbred, the less genetic potential that dog has. What that means is that the dog has less ability to improve a trait in his or her progeny.

Breeding Sibling to Sibling

Sibling inbreeding is not recommended.

Breeding a brother to sister is inbreeding and has the same pros and cons that are seen in the list above. However, it is important to mention a few things about this pairing over a parent to offspring.

First, breeding brother to sister can be illegal in some breed clubs. What this means is that you won't be able to register the puppies in the event of a litter. Second, in kennel clubs where it is legal, it should only be done if there is a strong reason, such as trying to lock in a trait.

One of the benefits of breeding siblings together, outside of having a male that compliments your female so close by, is that there is a bit more genetic diversity between siblings than parent to child.

But why is this? When two unrelated dogs mate, all of the puppies share similar genes but not all of the genes. Some will have more genes from their father and some will have more from their mother. This means that the sibling dogs could have different genes from each other.

In addition, if they are half siblings, that genetic diversity gets a bit stronger as they only share the genetic material from one parent.

However, they are still related and will share genes and traits. These shared traits have a higher chance of being passed onto the next generation of dogs.

Even still, with the cons of close inbreeding, it is often frowned upon to breed siblings, especially if you are not experienced and new to the world of breeding.

Breeding Parent to Offspring

Parent to offspring breedings should be avoided.

Breeding a parent to offspring is one of the closest types of inbreeding that you can do and results in a high COI. When this happens, the chance of inbreeding fatigue increases and there can be health and development problems with the puppies, including smaller size.

Again, like all inbreeding, the main reason for breeding parent to offspring is to lock in a trait. There is actually more of a chance of locking in that trait than with other combinations because of the high COI.

However, the risks are much higher and for that reason, I do not recommend inbreeding parent to offspring.

In the end, it is up to you on whether or not you want to take the risk that can occur with inbreeding. While there are benefits, I always advice on caution. Make sure that you know the good, the bad and the ugly of your dog's traits and are prepared to see both good and bad traits locked in. If in doubt, the best choice is to avoid inbreeding.