A question you ask yourself several times long before you decide to buy an out cross dog or breed a litter with one.
Is the health of a Mastiff really bad or do we have ‘bad luck’? Can we improve the health and prolonge its longevity by breeding within the breed? Is it necessary to out cross and use another breeds or are there alternatives? Is a random crossed dog on the internet healthier than a pedigree dog?

A lot of questions, you can’t answer right away. I have read a lot of material (mostly in English – I’m Dutch), talked to many breeders and people who have a lot of genetic knowledge. The research I did also gave me a lot of insights.

Is the health of the Mastiff really not so good or is it just our opinion? I did research it and published an article on my website a couple of months ago.  Hoe logisch is kyNOlogisch (I’m sorry, it’s in Dutch).  I received a lot of positive feedback and many people recognized it, even if the Mastiff is not ‘their’ breed.

In mai 2015 we decided to have a crossbred Mastiff in our pack: Freddy, with a Mastiff mother and a racing Greyhound father. We were blessed that Rhapsody a 100% pied Mastiff was going to live with us too. Freddy en Rhapsody have been bred by Gammonwood – Australia and have the same age. That gave us the opportunity to compare their development. We still think they are both great and complement our pack, each in their own way!

What does science say about out cross? 

A lot of research has been done on the consequences of inbreeding in the last decade and there is more to come. A few consequences that we see already or will see in the near future are:

  • Lower vitality (longevity of the Mastiff is now down to, on average, 6-7 jaar)
  • lower fertility (smaller litters and/or less successful breedings )
  • lower immune system (that means that Mastiffs get sick easier and it’s harder for them to recover)
  • More genetic disorders
  • Lower diversity (in an ideal world a living creature should have a 100% unique genes. Unfortunately that is not the case with a lot of the current pedigree dogs.)

Interesting articles and video’s about inbreeding are:

In case you don’t have the time to watch the video’s or read the articles;  Suppose your new boyfriend introduces you to a very important person in his life and this person is ánd his mother ánd his grandmother?? How crazy is that? Well it’s very common in pedigree land!

What is the opinion of the breeding clubs and Dutch Kennel Club about out cross?  

More and more breeding clubs and the Dutch Kennel Club realize that diversity of the gene pool is the necessary for a healthy dog.
The Dutch Kennel Club even made a plan where they state: ‘Genetic diversity is necessary to breed a healthy dog and therefor requires a big gene pool.'( Fairfokplan 2014)
Unfortunately the Dutch Kennel Club hasn’t come in action to improve the conditions to breed with a bigger gene pool. A mating between half-brother and half-sister is still allowed. Isn’t that totally ridicoulous?!
They did have a video promotion for pedigree dogs, who, per definition, have a smaller gene pool, because of their closed pedigree.  I’m happy there are several breeding clubs that introduced their own out cross program.

De KMSH (Belgian Kennel Club)  has published wonderful video’s about breeding in a healthy way taking inbreeding into account.  Sorry again in Dutch but most interesting to watch the videos of the KMSH !

A bigger gene pool within a breed

It is proven that a bigger gene pool – higher genetic diversity – in a population is crucial for the existence of a breed. So it is of the utmost importance that pedigree dogs don’t have the same ancesters.

You can improve the genetic diversity of a pup in relation to it’s parents by mating 2 inbred dogs. The pup will have 50% of the genes of the mother and 50% genes of the father. And if the parents are not related, the genes of both parents are not similar and the pup will have more unique genes than his parents. The most difficult thing is to find a Mastiff that is not related to your Mastiff… A few decades ago it was possible to find unrelated dogs within the breed in foreign countries, but that’s history.

COI of the Mastiff is 30%. That means that, on average, the genes of a Mastiff are unique for 70% – 30% of the genes are similar. The genes that are similar make it possible to capture specific characteristics, BUT they also increase the chance of hereditary diseases, lower longevity, immune system and fertility.

Unfortunately we still see several litter announcements these days where father and mother have the same ancestors and litter announcements where you can find one male 4-5 (!) times in the pedigree of a pup, based on 3-5 generations. Why would a breeder want to take that risk? An argument that we hear a lot is that they know the 2 individual dogs they want to mate are healthy.
They probably do not realize that by breeding these 2 related healthy dogs, they lower the genetic diversity of the puppy’s compared to the parents, which means they tear down the health system of the puppy’s.
So they think the puppy’s have a good change of being healthy because they breed with 2 healthy parents but do not realize that the puppy’s are basically unhealthier if the parents are related.

You can find more information about in this video about breeding and selection. (in Dutch)
The consequences of inbreeding are very well explained in this video.

Widening the gene pool by outcross

What if you breed 2 dogs of 2 different breeds? On one hand you add new genes to your breed which improves the potential health of your puppy. On the other hand you can not predict exactly what the character and looks of the puppy will be.
So by cross breeding you will find the characteristics of 2 breeds in the puppy and it is rather exciting to see what characteristics will prevail. But it also very interesting and you learn a lot!  You will learn to look at a dog and not a dog within a breed.

So an average cross bred dog is healthier than a pedigree dog?  

The genetic health basically depends on the genes of the dog. These genes should be a 100% unique. That way the dog will be able to fight intruders in his body when he gets sick and the change of developing new hereditary disorders is small.
BUT if both parents aren’t tested for hereditary disorders, there is still a change of health problems, although that chance is smaller than breeding 2 dogs of the same breed with the same hereditary disorders. The reason for that has to do with the place of that particular gene in the body of the dog. Dogs of the same breed have an equal gene structure. If the disordered genes are in the same place the change of hereditary disorders is bigger. On the other hand, it is not true that a dog with 100% unique genes is always healthy!

Not too long ago I read a post where somebody claimed to know what characteristics a cross bred puppy was going have. Stating the pup would develop specific characteristics of the father and other specific characteristics of the mother. And of course that is nonsense! You will only know once the dog is getting older.

Our ‘half Mastiff’

20 mei 2015; the day we heard Rhapsody was born and 2 days later Freddy would set foot on this earth. They are both bred by Gammonwood – Australie.

We started studying genetics a few years before they where born and saw the benefits of an out cross. We did some extra studying after knowing Freddy’s Daddy was a racing Greyhound. Would it help the Mastiff? Well, we thought it would and decided to add a male puppy to our pack.   Our Lovely Mastiff male died a year before he arrived, just before he turend 5 years old. Cause unknown. is immuun system was not strong enough to fight the gastrointestinal inflammation. We hoped he would turn as old as his dad (11 years) and grand dad (13 years) but unfortunately he didn’t. We still miss him!


The early death of our Mastiff male Dirk, and the outcome of research in several countries about the average age of a Mastiff being only 6-7 years these days, made us study pedigrees and genetics even more. We learned that it is not possible to exclude all disorders and excluding all dogs with a disorder is certainly not the answer (although some breeders and breeding clubs still think it is).
We learned that it is possible to make smart choices and therefor it is possible to exclude disorders if you test the dogs and know the basics about genetics. We have to make sure the gene pool is large and by excluding dogs from a gene pool, we will only create new health problem.

So, we were very curious about the (genetic) health of Freddy, our out cross; Racing Greyhound * Mastiff. And here they are:

  • Hips – excellent (HD-A)
  • Elbows – excellent (ED-0)
  • Eyes – excellent (free)
  • Heart – 2 what means good;  they could hear some heart murmur which is seen often with the Mastiff
  • DNA test – free of all hereditary disorders known at that time
  • GHI – Genetic Health Index 121 versus 100 for the average dog, most Mastiff score < 100
  • GD – Genetic Diversity 44.4 versus 31.3 for the average Mastiff

Unfortunately there are no tests available for predicting cancer. None cancer is rather common with Greyhound and Mastiff (apart from other forms of cancer – 15% of the Mastiff die of cancer). The breeder used her common sense here and used a champion Racing Greyhound that was 12 years old and healthy at the time of breeding the Mastiff.

Because Freddy (now 2,5 years old) is such a lovely dog with wonderful health results gives us enough reason to breed with him!

Out cross litter – F2

In november 2017 we are expecting puppy’s from Alex and Freddy. We are so excited! It is mating number 12 for us and only the first one and this last one succeeded. We have tried it all:  artificial insemination with frozen and fresh semen, natural breeding, different Mastiff males, different pedigrees, with help of a vet, without help of a vet and never successful. We even doubted Alex her futility after 4 matings. So we decided that her true love Freddy should have a change since he is old enough now. They had a natural breeding, just as it is supposed to be and last week we saw the little creatures on the ultrasound; she is pregnant!

Food for thought

Finally pregnant! In the last few years we did have the idea that the failure of breeding was just our problem, choice of partners,  food, radiation in the house – or on our land, you name it. Now we know less than 50% of the Mastiff breedings fail (based on the published information). We always refused to give the girls extra progesteron or whatever medication was offered. In our opinion the dogs have to do it on their own. And if they can’t do it their selves you have to ask yourself if the pups are meant to be born.

We hope the pregnancy will go ok so we can welcome lovely, healthy puppy’s in a few weeks and of course one of them will stay and live with us!

Questions you should ask your breeder:

  • What are the most common disorders in the breed?
  • Are the parents tested for these disorders?
  • Can I see the test results?
  • Are pedigrees of the parents available?
  • How many equal ancestors are in the pedigree of the pup (COI)?
  • Are the pups going to be chipped, registered and vaccinated?
  • Can I see the DNA registration of the parents?
  • Do we get a DNA profile of the puppy, so we know who the actual parents are?
  • In wat environment will the pups grow up?
  • Will the pups be socialist?
  • Please chacj the breeder via google and or Facebook

If the answers on your questions are positive, open and honoust, you will can may a good choice to buy the pup!

Mastiff 1911

Great Dane
(Greyhound * Mastiff)

Great Dane - Mastiff x Greyhound


Pup Freddy

Lovely Freddy

Freddy 1 year

Freddy & Alex

Freddy 18 months

Freddy - outcross 50% Mastiff - 50% Racing Greyhound

Playing together!

With his little ‘sister’

Dogsurvival 2017