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7 Health Concerns About Giant-Breed Dogs

If you’re considering a large dog for your next pet, make some room in your heart and your household.

Giant-breed dogs are labeled “seniors” after 5 years of age. By: peggycadigan

What size are the paw prints on your heart?

Dogs come in all shapes and sizes, and we gladly make room for them — and all their needs — in our households.

But what about those larger-than-my-sedan’s-interior dog breeds?

Keeping a giant-breed dog is a big commitment — in every sense of the word. If you apply the motto “bigger is better” to dogs, then you need to be prepared for what having an oversized pet in your family means.

The Gentle Giants

Many giant breeds have a reputation for being smart, dignified, courageous and loyal.

Typical examples include:

Many of these are known as canine “heroes,” such as the St. Bernard and Newfie, who show courage and endurance in extreme weather conditions to rescue people in distress.

But if you are tempted to save a place by the hearth for a giant-breed dog, best be aware of what you’re getting into.

1. Shorter Lifespan

Your giant-breed dog may make a big impact on your life, but brace yourself for the encounter to be short but sweet.

The saddest downside of that big size is their average lifespan is much shorter than that of their pint-sized canine cousins.

The average life expectancy for a Great Dane or Irish Wolfhound is just 7 years, Bernese Mountain Dog 8 years and Pyrenean Mountain Dog 9 years.

Of course, these are only averages, so some dogs live longer … and others shorter.

2. Hereditary Conditions

Any purebred dog has an increased chance of suffering from hereditary conditions passed down from parent to puppy.

This is the result of using a selective gene pool to breed dogs for a certain “pedigree” appearance.

This is as true for a Pug as it is for a Pyrenean, so it’s not a problem solely of the giant dog. You should do your homework first to see if you could cope should your pet be affected. The cost of meds for a giant dog is much more than for a toy breed.

Some examples of hereditary diseases in giant-breed dogs include:

  • St. Bernard: Dilated cardiomyopathy (enlarged heart leading to heart failure), hip and elbow dysplasia (poor joint anatomy leading to lameness), bone cancer, entropion and ectropion (turned in and droopy eyelids).
  • Irish Wolfhound: Atrial fibrillation (irregular heartbeat), portosystemic shunt (a blood vessel that bypasses the liver), Von Willebrand’s disease (a blood clotting disorder) and cancer of the bone or blood vessels.
  • Dogue de Bordeaux: Aortic stenosis (narrowing of the aorta) and dilated cardiomyopathy (enlarged heart).
  • Doberman and Great Dane: Wobbler syndrome, a neurologic disease that gives these dogs a wobbly gait.
Giant dogs experience a much longer growth period than most other dogs, but they also have a shorter lifespan. By: lostinfog

3. Longer Growth Period

Giant breeds have a lot of growing to do, and it takes up to 18 months for them to reach their adult size. During this time, their bones need careful nurturing to protect them from damage.

This means:

  • Feeding a diet suitable for “large-breed growth.” These diets supply the correct proportions of vital minerals for strong healthy bones. See our article “Yes, Large-Breed Dogs Really Do Need Special Food.”
  • Careful exercise. Growing bones and joints are more liable to damage, so it’s best to avoid extreme exercise until the dog is over 18 months of age.

4. Shorter Adult Phase

A giant-breed dog is considered adult between the age of 18 months and 5 years, after which he becomes “senior.”

5. Senior Giant Dogs

Giant dogs age more quickly than other breeds, and their organ function starts deteriorating after the age of 5, marking them as “senior.” Switching to a diet designed for older dogs reduces the strain on older organs and prolongs their active life.

Managing a giant dog with limited mobility because of stiff, sore joints can be challenging. Whereas you can carry a Chihuahua who tires on a walk, this isn’t possible for a Bernese Mountain Dog.

Consider using ramps to help the dog in and out of the car, and consider walking around the block several times rather than going for a long there-and-back walk.

Check out these humongous — and sweet — Irish wolfhounds:

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6. Large-Scale Costs

From the size of their meals and food costs to needing a large vehicle to transport them in comfort, everything about giant dogs is big. Unfortunately, this extends to the cost of routine treatments for fleas and worms — and should your giant dog require prescription medications, the cost can rapidly spiral.

With this in mind, insurance is essential.

7. Space Factors

A Great Dane with a wagging tail can cause havoc in a confined space. Make sure your giant dog has space to move around, and make plenty of space in your heart for a gentle giant.

As puppies, large-breed dogs drive their metabolic engines pretty hard. By: Jay Iwasaki

Why Don’t Giant-Breed Dogs Live Longer?

If elephants live for 70 years, why don’t Great Danes live longer than Chihuahuas?

It’s an acknowledged fact that large-breed dogs don’t live as long as smaller ones.

For example, here are some average lifespans:

  • Great Dane: 7 years
  • Chihuahua: 15 years
  • Leonberger: 8 years
  • Pomeranian: 14 years

Do the math and you can expect licks and wags for almost twice the time from a smaller dog.

But when you think about it, why is this? When giant animals, such as elephants, live as long as people, why does larger size means shorter life for dogs?

Science Thinks It Knows “Why”

The other side of the argument is to ask why smaller mammals, such as mice, lead shorter lives than elephants.

The answer is the smaller the mammal, the faster their metabolic rate. Their inner “engine” runs harder and faster, and burns out sooner.

Think of this as having a finite amount of energy programmed into the body, and a small animal uses their quotient up faster. However — and this is where it becomes relevant — this doesn’t hold true for dogs.

When you compare the metabolic rate of small dogs with large, then teacup-sized individuals have a relatively slower metabolic rate than you’d predict for their size and are relatively energy-efficient.

But this doesn’t tell us why big dogs lead shorter lives.

An antioxidant-rich diet may give your giant dog a longevity boost. By: Dallas Krentzel

Why Do Big Dogs Die Younger?

A research study at Colgate University looked into this question.

After taking tissue samples from a variety of different-sized dogs — both puppies and old timers — the research team grew cells from the samples in the lab and analyzed them to look for significant differences. And they found one.

Long story short: Large-breed puppies have a revved-up metabolism in early life. In other words, they’re driving their “engine” hard (just like those short-lived mice).

Indeed, they rev things so hard that those developing cells are overwhelmed with free radicals. These free radicals cause what’s called “oxidative damage.”

Oxidation is the same process that causes metal to rust — think of this happening inside cells, and you see the problem. That early push for growth sets up long-term cellular damage that programs in a shortened lifespan.

It’s a chicken-and-egg situation. Large-breed puppies have a phenomenal amount of growing to do and need rapidly metabolizing cells to do it.

Those hyperactive cells produce more waste products than the body can get rid of, which lights a fuse for self-destruction in the long term.

Ways to Help Your Giant-Breed Dog Live Longer

The obvious answer is, from a young age, feed a diet rich in antioxidants.

A bit like opening the garage door to let those toxic engine fumes out, antioxidants break down free radicals and take away their sting.

This is a new field of research, so feeding antioxidants isn’t yet backed up by science as a way to extend your giant dog’s life, but heck — what harm can it do?

This big Bullmastiff needs a little help from Dad:

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Vitamin E, the hero of antioxidants, can be found in fish oils (those wholesome omega-3 oils), green leafy vegetables, wheat germ, blueberries, cranberries and blackberries, among other things.

Obviously, a balanced diet is essential for healthy growing bones, so if you supplement your pup, get the advice of a veterinary nutritionist first.

Other ways to keep a giant dog around for longer include:

  • Screening parents: Many large dog breeds are associated with hereditary health disorders. Always source a puppy from responsible breeders who have screened the parent dogs.
  • Knowing your breed’s problems: Familiarize yourself with the health problems linked to your dog’s breed and be proactive. For example, a big issue with Dobermans is dilated cardiomyopathy. But yearly heart screening can identify dogs who would benefit from medication that can extend life by months or years.
  • Feeding age-related diets: From a growing puppy to a senior dog, feed a diet designed for both their size and age to nurture healthy organ function.
  • Taking preventive care: Prevent avoidable problems with regular vaccination or parasite control.
  • Feeding nutraceuticals: Consider food supplements to boost the immune system, encourage joint repair and have an antioxidant action.

Also, watch their weight — a lean waistline means a longer life.

Studies comparing litters of puppies showed those who were slim in the first year of life lived 2–3 years longer than their chubbier counterparts.

So there we have it. There’s no miracle answer for extending the life of your giant-breed dog, but you can definitely make a difference in their quality of life.


  • Breed Predispositions to Disease in Dog and Cats. Gough & Thomas. Publisher: Wiley-Blackwell. Second edition.


This pet health content was written by a veterinarian, Dr. Pippa Elliott, BVMS, MRCVS. It was last reviewed Oct. 13, 2018.