Hybrid Vigour – What does this really mean?

What is Hybrid Vigour?

It is the improved or increased function of any biological quality in a hybrid offspring or the increased vigour or general health, resistance to disease, and other superior qualities that are often manifested in hybrid organisms, especially plants and animals.

So essentially, hybrid vigour means that by crossing two unrelated animals to each other, you are decreasing the relatedness and therefore the overlap of genetic issues that are brought on by inbreeding and line breeding.

Why do we care about inbreeding and line breeding? 

All breeds were originally formed by using a form or inbreeding or line breeding. This is how they were able to create breeds that all looked the same. They bred dogs together with common lineage to get dogs that looked a like, establishing a type. This amplified certain genes in these dogs to be more predictable in looks, the problem is it also amplified ‘bad’ genes. Fast forward many years you have breeders overbreeding popular sires, a closed registry not allowing any new blood and culling dogs for their colour and nothing to do with health or genetics. Now, you have dogs that are more and more closely related.

We have seen that the more inbreeding that takes place, the lower the sperm count in males is, the lower conception rates are, the lower the litter sizes are and the lower dogs lifespan’s are. This has been seen in many different species, but for some reason dog breeders still are having a hard time dealing with this. Golden Retrievers are a perfect example of this. In the 1970’s Golden Retrievers lived to be between 16-17 years old, now Golden Retrievers have a life span of 9-10 years old. This can be attributed to dogs being too closely related, which results in getting two ‘bad’ genes, since one gene has to come from each parent.

How does this apply to Goldendoodles?

Well, lets break this down.

Golden Retrievers struggle with the following diseases:
Hip Dysplasia
Elbow Dysplasia
Eye Disease
Heart Disease
PRA
Muscular Dystrophy
Degenerative Myelopathy
Ichthyosis
Dystrophic Epidermolysis Bullosa
Sensory Ataxic Neuropathy

Poodles struggle with the following diseases:
Hip Dysplasia (not very common in Miniature Poodles, mostly found in Standard Poodles)
Eye Disease
Heart Disease
Patellar Luxation
Legge-Calve-Perthes
PRA
Von Willebrands Disease I
Von Willebrands Disease II
Gangliosidosis
Degenerative Myelopathy
Neonatal Encephalopathy with Seizures

Okay, now that we have looked at the common diseases amongst the two parent breeds, we can take a look at the ones that over lap. So, Hip Dysplasia, Eye Disease, Heart Disease, Degenerative Myelopathy and PRA are all in common. This means that because they are common in both breeds, you will not get the beneficial effects of hybrid vigour with these diseases. Now, as for Elbow Dysplasia, Muscular Dystrophy, Degenerative Myelopathy, Ichthyosis, Patellar Luxation, Legge-Calve-Perthes, Dystrophic Epidermolysis Bullosa, Sensory Ataxic Neuropathy, Gangliosidosis, Osteochondrodysplasia and Von Willebrands Disease I and II, you will see the health benefits of this cross.

What does this mean?

It is important to understand how most genetic diseases work. Most disorders are a result of a recessive gene. When you have dogs that are closely related, you are doubling up on genes too often and opening yourself up to more genetic disorders. This is one of the most common causes of disease among purebred dogs. It is important to breed ‘like’ to ‘like’ as, you want to breed for certain traits that you want exhibited in your breed, but in the process of breeding closely relates dogs together, we also having those recessive traits come to the surface more. This is why breeding Goldendoodles is considered healthier than the parent breeds because we have more genetic diversity in this cross and less doubling up of those genes that cause genetic issues.

So, shouldn’t health testing solve the problem?

Not entirely. We are able to identify many diseases now with genetic testing, but not all disorders that Poodles, Golden Retrievers or Goldendoodles are affected by have been identified. So, it is still very important to make sure that your dogs are not closely related, so no other disorders start effecting these breeds.

Do we lose hybrid vigour when we go past an F1 generation?

Yes and No. Yes, in theory the most hybrid vigour is achieved in a first generation because both parents are not closely related at all and there should be very little overlapping of genes. But, there is still more hybrid vigour in an F1b, F2b, F3 or Multigen, than there is in a purebred Golden or purebred Poodle. The only reason there could be less hybrid vigour in an F1b for instance than an F1 is there is Poodle on both sides, so you could see more overlapping of genes since the recessive genes could come from the Poodle side of both parent dogs.

Should we only breed F1’s then?

No, even though we know that a Golden and a Poodle bred together should not have much overlapping of genes and therefore should be healthier. There are many other things to consider when breeding Goldendoodles. Most F1’s are not good for allergy sufferers and are not usually non-shedding, both of which are not suitable for many families. Also, when breeding further generations you can selectively breed for specific traits in your breeding program and get more consistency, which is not found as often in an F1 generation. Also, even Multigenerational Goldendoodles still exhibit more hybrid vigour than a purebred does.

So, what is the solution?

We need to understand that the reason that a Poodle crossed with a Golden Retriever is healthier and has more hybrid vigour than a purebred Poodle or a purebred Golden Retriever is due to it not being closely related and therefore not having overlapping of ‘bad’ genes. So, it is not only better to breed two unrelated breeds together, but you should also use dogs from each of those breeds that are the most unrelated possible. This is also why when breeding you should track your bloodlines and make sure you are not breeding related dogs.

Are Goldendoodles always healthier than Poodles or Golden Retrievers?

No. When breeding a well bred, healthy Poodle to a well bred, healthy Golden Retriever, the Goldendoodle offspring should be healthier on average than both parent breeds. But, If you breed a poorly bred, not health tested Poodle to another poorly bred, not health tested Golden Retriever, you will not miraculously get healthy Goldendoodles. They may be healthier than their parents, but they won’t be healthier than a well bred, health tested Poodle or Golden Retriever from another line. Even though hybrid vigour does give a healthier outcome than the parents, if the parents are not healthy to begin with, you still won’t get a healthy puppy. It is always important to breed healthy parent breeds when producing Goldendoodles.

In Summary.

• Golden doodles are healthier and tend to live longer than both Parent breeds due to hybrid vigour.
• All Goldendoodle breeders should be testing for disease present in both breeds to make sure there is no overlapping of genetic disorders, just as you would if you are breeding the purebred parent.
• Even though we lose some hybrid vigour when breeding past an F1 generation, we are still seeing more hybrid vigour than we would see in the purebred dog. You can continue to optimize the health benefits of hybrid vigour in these generations by using unrelated dogs in both breeds to continue the lines.
• It is still important to breed past an F1 generation because we want more consistency in the Goldendoodle.
• Hybrid vigour is not an excuse for using improperly bred parent dogs. To optimize hybrid vigour always select well bred, health tested parents to produce Goldendoodles.