English Mastiff Health Testing

 

Breeding Is About Improvement, Not Perfection

At Muddy Mastiffs, we believe in radical transparency. On the rest of our website, you'll see us highlighting the strengths of our dogs, their pedigrees, accomplishments, and the traits we are proud to preserve. But this page exists for a different reason. Every experienced breeder knows the same truth: No bloodline is perfect.

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If you ever find a perfect bloodline, please let us know. We'd love to get some of those genetics ourselves.

The reality is that breeding is biology. Every bloodline has strengths. Every bloodline has weaknesses. Every bloodline has traits that breeders love and traits that breeders work to improve.

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One bloodline may produce exceptional show dogs but have a tendency toward higher prey drive. Another may have beautiful type but struggle with fertility. Another may produce wonderful mothers but lack size or substance. Another may dominate the show ring while carrying a structural issue breeders must carefully manage. The goal of ethical breeding is not to pretend these things do not exist. The goal is to understand them.

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A responsible breeder studies their dogs honestly, identifies areas for improvement, and then seeks complementary bloodlines that strengthen those weaknesses while preserving the traits that make the line valuable.

Generation after generation, breeders are assembling a puzzle. That is exactly what we are doing at Muddy Mastiffs.

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How Our Program Has Evolved

Our foundation female brought many qualities we wanted to preserve. She came from strong bloodlines, demonstrated excellent fertility, possessed outstanding mothering instincts, and consistently raised healthy puppies. She was on the smaller side, and we paired her with a tall male that had a big head, Bane. One of his ancestors was a European champion, giving our program some genetic diversity.

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The result was a generation of daughters that outgrew their mother and, we hope, retained her best qualities. What we did not anticipate was that they would become so tall that the first stud we attempted to use with them literally could not reach to breed them naturally. And he was a stocky boy. He just wasn't tall enough. LOL. I didn't even realize that was something that could happen until it happened to us.

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In hindsight, it was a good problem to have. It meant our first major breeding decision had accomplished exactly what we wanted: we had successfully added height and size to the line.

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The downside... it brought our program to a standstill. It had already been paused for a couple years due to my own health. And then it had to be paused an extra year or two while we searched for the right stud and waited for him to grow old enough. We were very picky in our requirements for a stud puppy. But we finally found Freedom. His father was 250 pounds, so we thought he would grow tall enough. And he did. His line also adds more substance to our tall dogs. And he's got the headpiece of a warrior and dark apricot brindling to die for.

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That experience heavily influenced our priorities and explains why my girls will be first time mommas at nearly 5 years old. Before investing thousands of dollars into advanced health testing, we first wanted to answer a more basic question: Could our line reproduce at all?

 

That may sound obvious, but fertility, natural breeding ability, pregnancy success, whelping ability, and maternal instincts are all traits that matter tremendously in a breeding program and are often overlooked in favor of more visible accomplishments. We knew of a least one dog on each side of the family that never had puppies, and we needed for verify that ours were actually fertile. And thank God, they were!

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In hindsight, perhaps all our worrying was a little silly, because every puppy in the world is produced by fertile parents. Lol. The things we go through as breeder.

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Anyway, that leads us to today. Now that we have our first two visibly pregnant females, we are getting really serious about health testing.

 

Timing is a factor. Even though our girls are almost 5 and eligible, we don't want to do their OFA x-rays until they have weaned their first litters. Our focus is just on keeping those babies healthy. Some will criticize us for our decision to breed Freedom for the first time before he turned two. But it was the right thing to do. Unfixed Mastiff females are at increased risk for Pyometra the longer they cycle without pregnancy. Their reproductive systems function a lot differently that humans. But that is a topic for another post. Our females are safe and fertile, and that is what matters. We also took into account that Mastiffs often have smaller litter on their first time, so we felt it was important to at least get them started.

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With that said, Freedom turns two in September, and we have to wait until then to get his official OFA x-rays done. In the mean time, he is starting his dog show career in June, right around the time his first puppies are due. Opal and Ivory will also complete their OFA x-rays after they turn two, which should be right around the time their first small litters go home.

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So we did what we could for this first round of litters. We sent all the parents' DNA into embark with great results.

 

And once timing permits, our plan is to take them all to a clinic and get all the OFA testing done. We could start to get results back as early as July 2026, but I would expect every dog in our kennel to have complete health testing done by February 2027. And from there we will just keep up on it. We will post results on our website, so if you do buy a puppy from us this round you can always check back later to see how it went.

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Ongoing Evaluation

Every dog in our program is continually evaluated. As Freedom matured, we noticed some additional skin beneath the eyes. At this time, he appears completely functional and happy. His eyelashes are not rubbing the eye surface, and he shows no signs of discomfort. The vet explained that it's not always something you can select for as a puppy, because it depends on how the dog grows. This breed is selected for big, wrinkly heads. And often that means extra skin. Our females have tighter eyes, which is one of the reasons we believe the pairing is complementary. He is bringing size and substance. And our girls are bringing tighter eyes and beautiful function and movement.

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Because transparency matters, we believe it is important to acknowledge what we observe and discuss openly. For example, if you were to get a foundation puppy from us that developed extra skin under they eye, we would also want you to know enough to select a mate like we are that has less skin.

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If a trait requires improvement, our approach is not to hide it, or pretend it does not exist. Our approach is to identify it, understand it, and make thoughtful breeding decisions that preserve the dog's strengths while selecting for improvement in future generations. That is how responsible breeding works.

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Health Testing and Genetic Screening

All of our breeding dogs have been fully DNA health tested with Embark DNA. They are all clear of over 270 genetic conditions, and everyone is clear of everything breed relevant. I plan to run a Type III Cystinuria test with another company, because Embark didn't have a test by that name. But they did test many types of it, and all were clear.

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Currently, our females are clear for all tested conditions. And they all have two copies of the good gene: Copper Toxicosis (Attenuating) (ATP7A, Labrador Retriever)

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Currently our male is clear for all breed relevant conditions, and he has one copy of the same good gene the girls have. And he is clear for everything else except being a carrier for one non-breed relevant gene: Laryngeal Paralysis and Polyneuropathy (CNTNAP1, Leonberger, Saint Bernard, and Labrador Retriever variant). This means he only inherited one copy of the bad gene, and neither he nor his puppies will be affected so long as he is only bred to clear females. If you do get a foundation puppy from him, you will want to DNA test it and if it is a carrier, only breed it to clear mates just like we are doing. If you do that you won't have a problem. When we save back our own puppies from him, our plan is to DNA test and only keep clear puppies. This, again, is how you build a program. Test everything you can, and improve with each generation.

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Looking Toward the Future

Our goals remain simple.

We want to continue improving:

• Size and substance

• Sound structure

• Fertility

• Maternal instincts

• Temperament

• Longevity

• Functional movement

• Overall breed type

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We also enjoy preserving and expanding the beautiful colors found within the breed, including rich brindles, dark apricots, and light fawns.

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Every generation should move us forward... not toward perfection, because perfection does not exist... But toward better dogs.

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For Future Breeders

If you purchase a foundation-quality puppy from us, we want you to have the information necessary to make good breeding decisions like we do. It's in our best interest to help you succeed. A successful breeding program is built by understanding the strengths and weaknesses of multiple bloodlines and combining them thoughtfully over time. You need all the information available in order to do that.

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We believe honesty serves the breed better than marketing. That is why this page exists.

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What We're Proud Of

While this page focuses on transparency and improvement, we are also proud of the strengths already present in our program. Our dogs consistently demonstrate strong fertility, excellent maternal instincts, good movement, stable temperaments, substantial size, and pedigrees containing numerous champions and grand champions. Our goal is not only to preserve those strengths, but to build upon them with each generation.

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We'll be the first to tell you that we are not perfect, but we are always trying to improve. And that, paired with our radical transparency is what makes us good breeders and valuable mentors for the new generation of breeders that will build on our work.