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How To Breed Bullmastiffs — Background, Breeding Practices, Nursing, etc.

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Published on
Sunday 31 December 2017
Last updated on
Tuesday 9 May 2023
How to breed bullmastiffs?
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If you are wondering how to breed Bullmastiff dogs, you have landed on the right article. We are going to explain to you the Bullmastiff breed background and history, but also focus on best breeding practices and health conditions plaguing the breed.

Breeding Bullmastiffs requires deep knowledge and love for the breed, just to get started with outlining a realistic, yet ambitious, Bullmastiff breeding program. This is a written document that will force you to establish clear short, mid, and long-term goals that are measurable. That way, every few months or years, you are able to measure your results (or lack thereof) and adjust.

Reach your perfect Bullmastiff dog specimen should be your life goal. Every decision you will make from this second onwards should be decided based on whether it is going to lead you to that perfect Bullmastiff, or not. Bullmastiff breeding requires canine genetics knowledge, and expertise in a lot more fields, but you can find that in our dog breeding guide.

Background of Bullmastiff Breeding

The Bullmastiff is a mix of 60% English Mastiff and 40% Bulldog, with its original Bulldog ancestor being an extinct breed now. It is part of a group of working dogs known as Molossers. This term refers to a group of dogs that include breeds like Great Danes, Saint Bernards, Cane Corso, and other Mastiff breeds that have a common ancestry in a dog that originated in what is now the region occupying Greece and Albania. They have very old ancestry.

Dogs of the Bullmastiff-type appear in statuary and literature going back thousands of years. Dogs similar in the build were used in the Roman empire as war dogs, and as dogs that fought against lions and bears in the Colosseum. Over the centuries, the breed diverged into many different sizes and shapes depending on the purposes for which they were used. The fierceness was retained in those breeds that were used for such brutal sports like bull-baiting (e.g. Bulldogs) and others became the guardians of herds (e.g. Great Pyrenees) and the rescuers of people (e.g. Saint Bernard.)

Bullmastiffs are a new breed relatively speaking and were bred in the late 1800s to guard the estates of English landed gentry from poachers. Their job was to silently approach and jump on and hold poachers for the gamekeepers. Because of this job they were nicknamed the “Gamekeeper’s Night Dog”. They were bred to be agile and aggressive. Males should weigh 110-130 pounds, and females 100- 120 pounds. The standards state that males should be 25-27 inches at the withers and females 24-26 inches. Bigger specimens detract from the agility of the animal and are not a plus in breeding. The Bullmastiff has an average lifespan of 7.5 years. Nearly half of its lifespan — to three and a half years — is spent growing.

The breed was first recognized in England in 1924. The American Kennel Club recognized the breed in 1933, and breed standards were published in 1935. The standards have been revised since that time. They were last revised in 1992. The standards allow three colors: fawn, red, and brindle (with combinations with the fawn or red.) Originally, the brindle coat was favored because it provided camouflage for a dog that was bred to surprise and restrain poachers. White on the coat is considered a flaw, and only a small patch on the chest is permitted. The black mask is a key identifying marking of the breed. The coat is short hair with some shedding. The coat does not require any complicated grooming. The body is muscular and compact. According to the standards, bullmastiffs convey a “keen” and “intelligent” expression. They are both “docile” and “strong.”

breeding healthy bullmastiffs
Be aware of hip dysplasia and lymphoma when breeding Bullmastiffs.

Health Concerns When Breeding Bullmastiffs

The Bullmastiff is a strong breed but it comes with a string of health conditions commonly occurring within its pool of dogs. First is the sheer size and weight of the dog: it is affecting the dog’s structure including joints and articulations. There are also some inherited cancers that are present including lymphomas.

Here is a list of the most common health concerns affecting the Bullmastiff breed of dogs.

Hip & Elbow Dysplasia

Hip dysplasia is a condition that affects many of the giant and large breeds. The ball joint of the hip is either imperfectly formed or the socket is shallow. Rarely, there is a complete dislocation. This condition has a genetic component, but there is no single gene responsible for the condition. The Orthopedic Foundation for Animals (OFA) is the organization that provides a database for the condition and provides certification of dogs cleared of it.

In the years 2011-2015, 6,221 bullmastiff dogs were tested for hip dysplasia, and 25.4% of them were found to be dysplastic. Dogs with hip dysplasia should not be bred. Hip dysplasia causes lameness in dogs and may be asymptomatic for many years. The imperfection in the joint makes the dogs, also, more vulnerable to painful arthritis in that joint.

Elbow dysplasia like hip dysplasia is common with the larger breeds. It, also, is screened by OFA. Dogs must be at least two years of age before they are fully screened. (Preliminary screenings can be done earlier, but full screenings are most relevant and reliable after a dog has finished growing.)

A competing newer test, the Pennhip, uses a number system to evaluate the degree of tightness in a dog’s hip and elbow joints. This evaluation requires dogs to be anesthetized prior to x-rays and evaluation being conducted. The Pennhip is a more costly test, but it can be conducted earlier than the OFA evaluation.

Of the two tests, breeders seem to prefer the older OFA evaluation. Which test provides the best predictor is still a subject of some debate with veterinarians being more inclined to favor the number-based Pennhip evaluation. The OFA evaluation relies on simple descriptive language and is sometimes criticized for being too subjective and open to manipulation.


Entropion is an eye condition in which the eyelid is turned in. Eyelashes then scratch the surface of the eye and cause irritation and damage. It is not a very serious condition. It is prevalent among those breeds that have deep wrinkles in the face and especially the brachycephalic breeds (pushed in faces, like Pugs.)

Simple surgery is needed to correct the problem. The correction of this eye condition does not bar a dog from conformation shows.


Hypothyroidism is a lack of thyroid hormone. It must be treated by medication. There is no cure usually for it. (Unless, of course, in the rare situation that it would be caused by a treatable tumor.)

A lack of thyroid hormone will make the dog easily fatigued, cause fur loss or poor quality fur, and predispose the dog to weight gain. It sometimes occurs in conjunction with congenital heart problems. Approximately half of the dogs with hypothyroidism have a genetically-caused autoimmune illness.

Most dogs will test positive for the condition by four years of age, but it can occur at any time in a dog’s life. This condition is called autoimmune thyroiditis There is a strong genetic component to this disease. Other causes of hypothyroidism of unknown cause are referred to as being idiopathic hypothyroidism.


Lymphoma is a cancer of the lymph glands and is the third most common cancers among dogs. It is especially prevalent in certain breeds. Dogs will usually have palpable tumors and will exhibit weight loss and fever. It will ultimately be fatal if not treated.


Treatment with various chemotherapy drugs can put it into remission. A little over half of the dogs treated with chemotherapy will receive life-extending remissions. About a quarter of dogs treated with chemotherapy will survive two years. Recent research has indicated a genetic cause of some lymphomas (e.g. Golden Retrievers have the highest incidence of lymphoma of any breed.)

Progressive retinal atrophy

Progressive retinal atrophy is a genetic condition that causes permanent blindness in dogs. Dogs will first exhibit trouble with navigating at night. As the rods of the eye deteriorates, the dog’s vision worsens. There is no cure for the condition. A dog with the condition will eventually go blind.

This eye disease has different genetic components. One type is caused by a dominant gene. There is a test for this type of PRA in bullmastiffs. Another type occurs by way of recessive inheritance. Some breeds can be tested to determine whether they are carriers of this second type. Bullmastiffs aren’t currently tested for the recessive type.


There are many different types of arthritis. Some kinds are autoimmune illnesses (like rheumatoid arthritis). Osteoarthritis is a disease that affects dogs much in the way it does humans. It is a disease that involves inflammation and pain of the joints because of wear and tear on the joints. Older dogs and overweight dogs have more risk of developing this painful illness.

Damage to joints caused by arthritis is not reversible. Typically dogs will display symptoms like difficulty changing positions (e.g. morning stiffness) or a general slowing down or avoidance of weight-bearing on painful joints. Treatment involves the use of nonsteroidal anti-inflammatory drugs (NSAIDs), prednisone or antibiotics (especially for infectious arthritis.)

Dogs, also, may contract Lyme disease which is a tick-borne disease. Lyme disease can cause arthritis and is treatable by specific kinds of antibiotics. Dogs with hip or elbow dysplasia are at greater risk for developing arthritis in these joints.

Gastric dilatation-volvulus (bloat)

Bloat is a life-threatening illness. In bloat, the stomach is distended and then twisted on its axis cutting off blood flow. If it isn’t treated, a dog will simply go into shock and die.

Symptoms include nonproductive vomiting and progressive weakness. Bloat is more common in the wide-chested breed of dogs. Its cause is not completely known, but it is thought to occur when dogs take in excessive air when drinking or eating. Preventive measures involve such things as putting a ball in the middle of a food dish to slow a dog down when it eats. Slow feeders are also a thing. If bloat is suspected, the dog should be taken in for immediate veterinary treatment. A vet will run a tube down the gullet of a dog to relieve the twisting of the stomach and release the air.

In a 2006 study of 166 dogs, the mortality rate for dogs suffering from bloat was 16.2%, and for dogs over the age of ten years, 21%. Approximately, three-quarters of the dogs that survived bloat went on to have another incident. Because of the high rate of recurrence, some veterinarians recommend a prophylactic surgery that involves stapling the stomach so it does not twist. Great Danes have the highest incidence of bloat, but it can happen to any breed of dog.

bullmastiff breeding years
Bullmastiff males and females take three years to fully mature. The breed’s lifespan is short. Therefore, there are only a few years of prime-time Bullmastiff breeding.

Best Practices When Breeding Bullmastiffs?

Once you make sure your Bullmastiff breeding stock is cleared of the abovementioned common health conditions, you can start focusing on breeding your healthy dogs. We have rounded up the most important best practices that are specific to breeding bullmastiffs of better quality than what is currently available.

This is what dog breeding is about: making sure your next generation is always better than your previous.

Average Litter Size

Bullmastiffs have larger than average litters. In fact, its close cousin, the Neapolitan Mastiff, holds the world record for the largest litter of 24 puppies. The average litter size for bullmastiffs is eight puppies. We have written in the past a comprehensive article explaining the important factors intervening in the size of a litter.

Cesarean Sections

Bullmastiff puppies frequently must be delivered by C-section. It is common for brachycephalic breeds to have difficulty in natural deliveries. Dystocia is a condition when the puppy’s head or body is too large for a natural delivery — there is a disproportion between the bitch’s birth canal and the puppy. The puppy, then, gets stuck. A puppy stuck in this way can kill both the puppy and the bitch; and other puppies not yet born, too. It is a medical emergency.

[pullquote-right]Reach your perfect Bullmastiff dog specimen should be your life goal.[/pullquote-right]


The breed, also, has a higher incidence of stillborn puppies. A higher risk of stillbirth and neonatal deaths may be an artifact of the large percentage of litters that require surgical delivery or may be related to the anatomy of the dogs themselves.

Breeding Period

The number of reproductive years for a bullmastiff are short compared to other dogs. The breed is not an especially long-lived dog. Many of the conditions that plague the breed do not crop up until the dog is fully grown which can be as late as three years of age. Overall, the Bullmastiff breed is one of the more costly ones to invest in. In the United States, there are only a little over a couple of dozen breeders that are listed on the club’s website. The prevalence of hip and elbow dysplasia alone removes many dogs from the breeding pool (statistically a quarter of them.)

Bullmastiffs are large dogs with often large litters. Though they do not need much space to be happy, their size necessitates a home or outdoor kennel large enough to accommodate them. These dogs are heat sensitive, and can’t be left outside in hot weather. They can easily suffer from heatstroke. Bitches will need to whelp indoors in temperature-controlled surroundings.

Temperament & Trainability

Bullmastiffs have docile temperaments with their families. They are lovable family dogs. These dogs are reported to be good with children. Their large size can make them unintentionally dangerous to smaller children. They are bred to be loyal and protective. They do have a propensity to drool quite a bit. They, also, make an assortment of noises like snoring, grunting, etc. They aren’t barkers, though. They are keenly aware of any changes in their surroundings and need no specific training to guard their homes and their people. Male dogs do not generally coexist well with other male dogs. They have an average prey instinct and have varying success with living with other domesticated animals (e.g. cats).


Many of the breeds have a reputation for having an independent streak. They need to have structure and be given early obedience training. They are not a breed that has much patience for repetitive or drill-like training. Owners of this breed should take a firm lead in setting limits for their dogs. Bullmastiffs that understand their place in the family hierarchy are trainable and eager to please.

Future of Bullmastiff Breeding

The future of Bullmastiff breeding is about bettering the health of the overall population of purebred Bullmastiffs. This is only achieved by convincing every single Bullmastiff breeder to stop breeding unhealthy dogs they may have. Which in turn requires breeders to health check all their dams and studs, and increase their expenses if they weren’t doing it up until now.

Because hip dysplasia and many other conditions are plaguing the breed, those invested in Bullmastiff breeding must absolutely focus on health and conformation. A lot of breeds are getting smaller and smaller, which has created even more demand for regular-sized and large dog breeds, including Bullmastiffs. Breeders should avoid trying to breed bigger or smaller, since the breed is very stable in its current physical appearance, and Bullmastiffs are very balanced in comparison to many other breeds out there.

breeding Bull Mastiffs
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2 comments on “How To Breed Bullmastiffs — Background, Breeding Practices, Nursing, etc.”

  1. BJ

    If i purchase a female that is a year old and papered with a non- breeding condition from an owner that is reselling that dog can i breed the dog. I’m not asking for the registration papers

  2. BJ why would you purchase a dog with a limited registration or a non breeding condition if you want to breed the dog? There very well could be some defect in or disqualifier from the breed standard in your dog that was observed by the breeder. For this reason many breeders don’t want their pups to be bred. Maybe you should contact the breeder and inquire. Hopefully this helps.

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