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Experimental Journey

An unsatisfying ending to a controversial Mastiff crossbreeding project


Editor’s Note: This article may raise strong feelings in some readers. It certainly did with me. As a diehard advocate of purebred dogs, I disagree with the premise of Jennifer Perry’s experimental Mastiff-Greyhound breeding — that crossbreeding to add hybrid vigor to the former is necessary, or advisable.

But I am publishing it here for three reasons: First, I ran the initial story when Jennifer embarked on her backcross project, and I was curious to see how it had concluded, as seven years have passed. (To that end, I asked Jennifer to write this update, not the other way around.) Second, unlike those breeders in a seemingly endless conga line to create dubious new canine mash-ups, from XL Bullies to the so-called American Molossus, Jennifer was interested in continuing an established, centuries-old one. And, finally, I consider myself a truth seeker, and this is Jennifer’s truth — if even if her approach flies in the face of what is considered acceptable among mainstream purebred-dog breeders.

I, for one, am disappointed that Jennifer did not see her project to its final conclusion. And it turns out crossbreeding does not eliminate the risk of fatal heritable disease, as she learned all too painfully.

So, read on, and draw your own conclusions.


In 2015, when we first embarked on our project to bring some fresh genetic diversity to our purebred Mastiffs, we were filled with excitement and curiosity. Would it really be possible to outcross to another breed and return to Mastiff type in just three generations, as other outcross projects had shown?

We decided to give it a try, and what an incredible journey it’s been. Full of bumps and turns, wonder, joy and tears.

In May 2015, our first outcross litter was born, and we fondly referred to them as the Greiffs. They were the results of crossing our brindle Mastiff bitch to a renowned racing Greyhound stud dog. Having only had Mastiff litters in the past, the Greiff puppies looked incredibly strange to us when they were born, but, boy, didn’t they grow up to be fine-looking dogs. Some people commented that we had just produced a litter of common pig-hunting dogs, but the Greiffs were nothing of the sort. The whole litter was very consistent in type, as you would expect from a first-generation cross between two pure breeds. They were large, refined and beautifully structured. For us, at least, it was simply impossible not to admire them. Torpedo, one of the bitches from the litter, is still my favorite dog of all time, and I know my ex-husband felt the same way about Meer, the male Greiff that he kept from the litter.


Some offspring from the first-generation Greiff liter: Torpedo (top left), Hedge (top right), Pitch (bottom left) and Freddy (bottom right).


My marriage ended in 2015, not long after the Greiffs were born. Much changed after that. The things that my ex-husband and I had planned to do regarding the breeding of our Mastiffs mostly fizzled out. Effectively the divorce spelled the end of our Mastiff breeding kennel, and the next few years were spent just adjusting to my new life and responsibilities.

By 2018 and with the Greiffs now fully grown and health-tested, the temptation to do a backcross breeding had become quite overwhelming for me. With the support of my new husband, I decided to breed my F1 bitch, Torpedo, to one of my purebred Mastiff dogs using frozen semen. It was a poorly timed insemination, and a wonder that we got anything from the breeding at all, but on July 20, 2018, one magnificent F2 puppy was born. We named her Magna. 


Magna, the second-generation singleton.


We got really lucky with Magna, as she turned out to be very Mastiff like. The F2 generation is where the most variation in type occurs, so our singleton puppy could have been a lot more Greyhound like, but she wasn’t. I’m always in awe of how genetics work when I look at Torpedo and Magna sitting together.


Top left: Magna, all grown up. Top right: Magna (foreground) with her mother Torpedo.


In 2019, I decided to try for a few more F2 generation pups, seeing as only one had been born. We did a natural mating between my solid-black F1 bitch and my 7-year-old brindle pied Mastiff, Chimes, the last of my purebred male Mastiffs. Given Chimes’ age and the fact that he’d never been bred before, I knew it was unlikely to be a large litter, and it wasn’t. Only three pups were born. Two solid-black males, Odin and Loki, and one pied female who we named Lydian.  


Top left: Lydian and her brothers Loki and Odin. Top right and below: Loki and Lydian.


Sadly, we lost Loki when he was only seven months old due to a rare sex-linked blood disorder similar to hemophilia. We lost Lydian in early 2023 to a venomous snake bite.  She was coming up to four years of age. Lydian was lovely bitch. A little more Greyhound like than Magna, but still a very large and refined-looking girl. Odin is still alive and well. He lives with a dear friend of ours.






Since breeding our last litter, a lot of people have asked me if I will go on to breed an F3 litter, and the answer to that is no. Despite the F3 generation being where breed type gets consolidated, and despite there being no doubt in my mind that my F2 bitch, Magna, could produce a litter of pups that conforms beautifully to purebred Mastiff type, it’s just not something I plan to do.

If I were to breed an F3 litter, I would need to find a suitable purebred male Mastiff to use over Magna, and no breeder here can offer me one without risking their breeders license and registration. The Australian National Kennel Club simply does not permit crossbreeding. I had to give up my ANKC membership and my Gammonwood breeders prefix in order to do what I did. An F3 generation breeding should be undertaken here with the sanctioning of a breed club and the national kennel club so as not to de-register or stigmatize any breeders.


Above: Zara, the purebred Mastiff dam of the F3 puppies bred in the Netherlands. Below: The sire, Brommer, an F2 from the crossed-bred Mastiff/Greyhound line.


There was an F3 generation litter bred in the Netherlands by Ange De Hoog originating from one of our F1 Greiffs. Ange bred her purebred Mastiff bitch Zara to Brommer, an F2 generation dog bred in Holland by Gaby Bemelen.  Brommer’s sire was Freddy, the F1 Greiff that we sent to Gaby in 2015. Gaby had bred Freddy to her purebred Mastiff bitch, Alex, and Brommer was one of the resulting offspring. The F2 generation bred By Gaby in Holland got off a little bit on the backfoot as Freddy, the Greiff that we sent to Gaby, grew up to be the most Greyhound-like male out of all the F1 males. Returning to type through backcrossing can be easier if you select dogs for breeding that phenotypically lean closest to the breed you are trying to get back to. That being said, the F3 generation dogs still turned out to be very Mastiff-like both in looks and temperament.

Here is a gallery of some of the F3 dogs bred by Ange in the Netherlands.


Jackie, an F3 female owned by Albertine Hamer.


Jakke, an F3 male owned by Ka Tia.


Lido, an F3 female owned by Marion Linders.


Noor, an F3 female owned by Alma Vos.


Molly, an F3 female owned by Christa Sevenich.


Irida, an F3 female owned by Claudia Kronbiegel.


Dirk (at left), an F3 male owned by Resie Robbers.


Lana, an F3 female owned by Peter Schotte.


When I look back on the past eight and half years, I acknowledge how much my views and understanding of the breeding of animals have changed. I still love Mastiffs (and many other types of purebred dogs), but I’m not hung up on breed purity like I used to be. I firmly believe that the pursuit of breed type and temperament should be done in conjunction with the pursuit of hybrid vigor, especially nowadays, when the effective population size of most gene pools is so small. What good is a typey-looking animal if it isn’t robust and beaming with good health? Sound and healthy animals emit a radiance of their own that is hard to parallel. Not all the dogs I bred turned out to be perfectly healthy, but I certainly did notice a big difference in overall health and vitality among the majority of my outcrossed dogs.

I can’t help but feel sad for purebred dogs (and purebred animals of many other species) whose breeders still apply the same old mantras of pure breeding, like believing that we can fully know our lines, therefore it’s OK to come in close or the bemoaning of the possibility of some unwanted traits popping up down the track if a breeding is done with anything too dissimilar. This can surely happen, but the long-term benefits to the dog far outweigh any minor faults that may occur. I see it all the time in poultry. Breeders go on and on about type being the most important thing. They share blueprints for how to linebreed to lock in type. The most typey hens I ever bought cost me hundreds of dollars, and they were stunning, but one died of unknown causes after six months and the other lived on but could never brood properly and was basically infertile. 

When I see breeders spending a fortune acquiring perceived unrelated bloodlines because they’re trying to do the right thing and not breed too closely, I sigh. I wonder why they don’t use that money instead on their children or others who are dear to them. They could easily not breed closely if they outcrossed. It’s just a matter of knowing roughly what to expect from the genotypes you are working with and knowing how to backcross. It can seem complicated, but it’s really very simple.


Above: The author's husband with three of their Greiffs. Below: The composition of the photo was inspired by this 1835 engraving, Keeper and Deer Hounds.


If I had the chance to do things over again, I don’t think I’d change much, except perhaps to change the breed I chose to use as an outcross. Although the Greyhound is closely aligned genetically to the Mastiff, and I feel that I gained more for the Mastiff overall by using a Greyhound, it would have been much easier on me personally if I had chosen a breed phenotypically more resembling the Mastiff. The gains in genetic diversity would have been comparable, and it would have been easier for other Mastiff breeders to have accepted and warmed to the project. Helping them to realize sooner rather than later the important role I believe outcrossing will have in the future of purebred dogs.

If I have any useful advice to give to other purebred dog breeders, it is to not wait till it’s too late! Outcrossing to other breeds can so easily reverse many of the problems caused from breeding dogs within small gene pools who share high degrees of relatedness. Things such as lack of intelligence and vigor, infection and lack of resistance to disease, mental disorders and aggression, loose skin and skin problems, abnormal bone growth, shrinking size, infertility, bloat and a whole host of other disorders. The more disorders the dogs acquire due to inbreeding depression, the harder it will be to bring them back. Starting an outcross project with predominately healthy dogs will give you the best chance of getting back to correct breed type and temperament. Alternatively, breeders can just keep kicking the can down the road and hoping for the best, but that’s not a formula I can subscribe to anymore. I’d rather have a few strange-looking Greiffs by my side.  



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