Bull Mastweiler: Your Guide To The Rottweiler Bullmastiff Mix

A rottweiler and a bullmastiff bred together makes the Bullmastweiler

The Bull Mastweiler is a mixed dog whose intimidating looks cover up a calm, gentle demeanor. They’re a cross between the Bullmastiff and Rottweiler, two popular, powerful breeds, resulting in the ideal guard dog. These large dogs are relentlessly loyal to their owners and will jump into defense whenever necessary.

These family-oriented, protective dogs possess ideal qualities and are best for confident dog owners.  If the Bull Mastweiler sounds like you and you’ve been eying the breed, you need to learn more about them. Temperament, space, and diet requirements determine if a dog fits your lifestyle, so read on to decided if this is good dog for you.

History of the Bullmastiff Rottweiler Mix: Where Do They Come from?

Bull Mastweilers are a crossbreed that has existed for decades, although their exact history is not documented. Since both the Rottweiler and the Bullmastiff are powerful sentry dogs and family guardians, it’s not that uncommon for people to mix these two breeds. It’s not quite right to call them a designer breed, since that term usually brings to mind dogs like Doodles. More often, the Bullmastweiler is bred in an effort to create a scary looking guard dog with an intimidating presence, like the Rotticorso or the Bullweiler.

Knowing about the parent breeds’ origin and development provides insight into the mixed dog’s history and purpose. The Rottweiler, in particular, has a lengthy and windy history with roots in medieval times. Both parent breeds were bred for a strikingly similar purpose of protecting and controlling livestock, with only a geographical difference.

History of the Rottweiler

This muscular working dog came from Germany and descended from cattle-driving dogs used by the roman legions. After the Romans abandoned the region, the dogs left in the vicinity of modern-day Rottweil, Germany, were used as the developing stock of today’s Rottweiler.

Back in the day, Rottweilers protected and moved herds and meat, earning them the name Rottweiler Metzgerhund, or Butcher’s Dog of Rottweil. After the rail came and their livestock career ended, Rotties returned to significance after WW1 and 11 as police and military dogs. Today Rotties are mainly seen as valued pets and family members.

History of the Bullmastiff

In the late 1800s in England, the story of the Bullmastiff began. The aim was to have a faster dog than the Mastiff and a larger, more retrained dog than the old English Bulldog. Undocumented references are made to crosses between Old English Mastiffs and English Bulldogs for guarding and bullbaiting as early as the 1700s.

Bullmastiffs were bred to keep off poachers who threatened gameland in England, scoring them the name “The Gamekeeper’s Night Dog.” Their sheer strength, size, and speed allowed them to pin down poachers. All while being tractable enough to let them go once gamekeepers commanded. Today, Bullmastiff fanciers are on the rise thanks to their calm and brave personalities.

What are the Physical Features of a Bull Mastweiler?


Height 23 to 27 inches (55 to 69 cm)
Weight 80 to 135 lbs ( 36 to 60 kg)
Color Black & tan, black & rust, fawn, red, fawn brindle, red brindle
Nose Dark, broad nose
Eyes Medium-sized dark brown or dark hazel eyes
Coat Short to medium-length dense, coarse, double coat

Bull Mastweilers are characteristically stocky and heavily built, irrespective of the dominant genes. Other than a significant physique, a Bull Mastweiler’s appearance can vary greatly, especially in color. It’s not usual to find a puppy with rust-colored markings of the Rottie and another in full fawn all in the same litter.

Keep in mind, most Mastweilers don’t inherit the bulkiness of their parent breeds. When the Rottweiler and Bullmastiff is bred together, one often gets a slightly smaller, sleeker, and more athletic dog than the Bullmastiff.

Still, these well-muscled dogs with squared heads and loose flews that make them adorable droolers. A large, powerful body gives the Bull Mastweiler a Mastiff look, intimidating to anyone unaware of the sweet personality beneath.

General Care of the Bullmastiff Rottweiler Mix


Hypoallergenic Not hypoallergenic
Shedding Moderate shedding that increases during shedding seasons
Lifespan 7 to 10 years
Exercise 60 to 90 minutes daily exercise
Temperament Affectionate, agreeable, intelligent, and loyal. Great family protector
Trainability Easily trainable but can be strong-willed. Early training critical


This is a medium-energy breed that needs about 60 minutes of daily exercise. Mental and physical stimulation is essential to avoid boredom, as they can become destructive. Typically, they love to chew on anything, so make sure they have plenty of chew toys. Break down exercise into smaller sessions to avoid strenuous breathing.

As a brachycephalic (short-nosed) breed, Bull Mastweilers must be closely monitored during exercise to avoid breathing issues. Avoid taking your dogs for intense physical activity when it’s hot outside to avoid a heat stroke.


Due to their large size and energy, Mastweilers are not ideal in small spaces.

A fenced home with a fenced yard is the most favorable option to give them some roaming room. Keep in mind the temperature to avoid breathing issues and heat stroke. You can turn on the AC when the house gets too hot.

Food & Diet Requirements

Bull Mastweilers are known to pile on the pounds and should be closely watched to avoid obesity. A high-protein diet with at least 25% protein for adults and 30 to 40% for seniors is generally fine. This percentage can change depending on whether your dog has renal issues or congenital liver shunts.

A Bull Mastweiler’s diet depends on their weight, mostly indicated at the back of most commercial foods. A vet will check your dog for underlying medical conditions like endocrine and renal issues that would affect diet and advise you on the right one.

It’s best to split meals into 2 to 3 portions to prevent the dog from eating too fast and avoid the bloat (GDV). They will do well on well-balanced dry, homemade, or raw diets. However, consult your vet before sticking to a raw diet to avoid nutritional deficiencies or excesses.


Bull Mastweilers have relatively minimal grooming requirements owing to their short coats. A brush-through with a soft bristle brush every 2 to 3 times per week removes shed hair and distributes oil. Monthly washes or every six weeks are generally adequate.

Special care should be taken if the dog inherits the Bullmastiff folds. These folds could trap moisture and food particles causing nasty infections and odor. Brush the teeth at least twice a week, especially for these brachycephalic breeds, and trim the nails every two weeks or so. Additionally, the ears should be regularly cleaned with a vet-approved solution.

The Health of a Bullmastiff Rottweiler Mix

Mixed breeds are generally healthier than their purebred fellows, and Bull Mastweilers are no exception. Mixed breeds are prone to health issues found in the parent breeds, such as bone problems in the heavy-boned Bullmastiff.

Parent breeds that undergo genetic tests like hip and elbow evaluation, hypothyroid, cardiac evaluation and ophthalmologist tests have healthier offspring.

Hip and elbow dysplasia A developmental issue if the hip or elbow joint, causing lameness, pain, and osteoarthritis
Bone cancer and other cancer forms Both parent breeds are prone to different forms of cancer.
Osteochondritis Dessicans) A condition where joint cartilage dies due to lack of blood flow
Heart issues Heart problems such as dilated cardiomyopathy (enlarged heart) are common.
Eye issues They can experience problems with the eyes, such as progressive retinal atrophy.
Hypothyroidism Also called underactive thyroid, where the thyroid gland doesn’t create enough thyroid hormone.
Aortic Stenosis. A disease of the heart valve
Allergies Including contact dermatitis
Gastric Dilation and Volvulus The stomach fills with gas and twists. Common in deep-chested dogs.

What is a Bull Mastweiler’s Life Expectancy?

Bull Mastweilers have a life expectancy of 7 to 10 years. Larger dogs typically live shorter lives than the smaller ones because they age faster and experience age-related issues faster. Nutrition, exercise, and medical check-ups determine how long your Bull Mastweiler will live.

The Trainability of a Bull Mastweiler: Temperament and Intelligence

Bull Mastweilers are alert, protective, obedient, affection-full, gentle giants. These loyal canines may be wary of strangers at first due to their guardian roots. They can make good-natured pets and are good with kids, but they must be supervised around them because of their large size and power.

Bull Mastweilers are trainable because they’re moderately intelligent dogs, mostly because of the smart Rott genes. They can be strong-willed and choose not to listen, but their strong will to please and obedience overshadow this. Early training and socialization leave you with a well-natured pet.

However, it’s important to note that this dog will not have the same drive to work as a working-line Rottweiler. Bullmastiffs are usually low-drive dogs who prefer to nap and cuddle than do any major work. This makes many Mastweilers no good for sports or excessive training. They can also be stubborn and independent. They like to work for praise and treats, but grow bored of repetition.  Usually, they have a reasonable urge to defend, but not much in terms of the prey drive we look for the higher levels of dog training.

Bullmastiffs are usually gentle dogs who can’t handle a harsh word. They are extremely attached to their owners and have plenty of emotional intelligence (but not so much of the other kinds of intelligence). The result is that much of what makes a Rottweiler tick will be watered down in the Mastweiler. Meaning they are typically not as smart or as eager to work, but they do love to take over the bed!

Are Bull Mastweilers Good with Other Pets?


These dogs are highly territorial and may react even when slightly threatened, so they’re not the best with other pets. They need plenty of socialization with all kinds of animals while young, as they do enjoy chasing and mauling smaller creatures. It is also vital not to keep your Mastweiler with another large dog of the same gender. Same sex aggression is very common in these dogs.

While there are owners who have no problem keeping powerful large dogs of the same gender together, these are usually either very experienced handlers, or people who got luck with their dogs’ temperaments. We strongly advise that if you have a large dog already at home, do not get Mastweiler of the same sex. Keeping powerful dogs of the opposite sex together are a better bet to avoid fighting.

Proper socialization from puppyhood increases their chances of doing well with other animals. However, even this isn’t a sure approach for a multi-household pet with this mixed dog.

Suitable Homes: Are Bull Mastweilers Good Pets?

Bull Mastweilers make great pets when trained and socialized properly. They’re not hypoallergenic and unsuitable for allergic people. They can live in a household with children, provided their interactions are always monitored. People with an moderately active lifestyle are best for this breed.

How Much Does a Bull Mastweiler Cost?

Mixed breeds are generally cheaper than purebred dogs, and you may find these mixes at $500 to $1000. You can also adopt a Bull Mastweiler for about $300 to cover vaccination and other medical costs. Be wary of extremely cheap puppies since most come from backyard breeders.

Final Thoughts

Bull Mastweilers are a great mix of companion and guard dog. They have a fearless but loving personality and are loyal to their owners to a fault. Bull Mastweilers are Rottweiler and Bullmastiff mixes, and you can either buy from a reputable breeder or adopt one from a shelter.


About The Rotty lover 2159 Articles
My name is Dr. Winnie. I earned a Bachelor of Science in Psychology from Duke University, a Masters of Science in Biology from St Georges University, and graduated from the University of Pretoria Veterinary School in South Africa. I have been an animal lover and owners all my life having owned a Rottweiler named Duke, a Pekingese named Athena and now a Bull Mastiff named George, also known as big G! I'm also an amateur equestrian and love working with horses. I'm a full-time Veterinarian in South Africa specializing in internal medicine for large breed dogs. I enjoy spending time with my husband, 2 kids and Big G in my free time. Author and Contribturor at SeniorTailWaggers, A Love of Rottweilers, DogsCatsPets and TheDogsBone