Large Dog Growth: A Practical Guide for 2026

Is your 3-month-old Newfoundland already 15 kilos, and you’re wondering whether that’s normal? Or maybe it’s the sound of those oversized paws pounding across the floor like a tiny pony that has you worried.

You’re far from alone. When I adopted my first Saint Bernard, I found myself checking his size every week, convinced he had suddenly grown overnight.

The tricky part is that no one really teaches you how to track this rapid growth without becoming obsessed with the scale.

The good news is that once you know the difference between healthy growth and a problem that needs attention, you can give your giant-breed puppy the best possible start in life.

Here’s a simple guide to help you get through this exciting stage with confidence.

Rapid growth: when your puppy starts turning into a giant

If it feels as though your Leonberger puppy has doubled in size overnight, that sensation is not far from the truth. Large-breed puppies grow at remarkable speed, especially between 2 and 8 months of age.

This phase can be nerve-racking. One day your puppy fits neatly into his bed; the next, his legs seem to hang over the edges. A common mistake is trying to slow growth by cutting back on food portions.

Key figure: A large-breed puppy can gain up to 2 kg per week during the peak growth period.

Despite what many people assume, that rapid pace is completely normal. Your job is not to slow it down, but to support it in the healthiest way possible.

Specialized nutrition: the fuel your giant puppy needs

When I fed my first Mastiff a standard puppy food, I quickly learned how much that choice can affect developing joints.

Large breeds need a very precise balance of calcium and phosphorus. Too much calcium can increase the risk of bone abnormalities; too little can weaken skeletal development and put stress on the joints.

Personal tip: I always check that the food is labeled “for large breeds” and that the calcium-to-phosphorus ratio falls between 1.2 and 1.8.

Forget about feeding “by eye.” A growing Pyrenean Shepherd has specific nutritional needs, calculated according to age and current weight. Portion size matters, but so does the quality and balance of the formula.

It is also worth remembering that growth is not only about calories. A well-designed large-breed diet helps support steady development rather than encouraging a puppy to grow too fast, which can place extra strain on bones and joints.

Monitoring growth without becoming obsessive

A number on the scale is useful, but it does not tell the whole story. A puppy’s body shape often reveals more than his weight alone.

Run your hands gently over his ribs. You should be able to feel them easily without pressing hard. Then look at him from the side: even with a thick coat, his waist should still be visible.

Pay special attention to the joints. If your puppy starts limping after playtime, do not brush it off. Large breeds are particularly vulnerable to early signs of dysplasia, and acting quickly can make a real difference.

Exercise that supports growth without overloading the body

The image of a Rottweiler puppy running for hours may seem harmless, but it is actually a bad idea. Joints that are still developing can be damaged by repetitive high-impact exercise.

Short but frequent walks are a much better option. Swimming is one of the best forms of exercise for a young large-breed dog because it builds muscle without stressing the bones.

This gentler approach helps your puppy develop strength gradually, in line with the pace at which his skeleton is maturing.

Did you know? The growth plates in large-breed dogs do not fully close until between 18 and 24 months, compared with around 12 months for small breeds.

That means your giant puppy is still growing well beyond his first birthday.

Veterinary checkups that make a real difference

Routine vaccinations are important, but they are not enough on their own. Your veterinarian can spot growth issues that are not visible to the naked eye.

Monthly checkups are a good idea during the first 6 months, followed by visits every three months until 18 months of age. These appointments help adjust nutrition and detect possible joint issues early.

Some veterinarians also recommend preventive X-rays around 4 to 6 months to check the development of the hips and elbows.

Even if your puppy seems healthy, these regular visits provide reassurance and help you stay one step ahead of problems that are easier to manage when caught early.

Growing up with confidence alongside your giant companion

Raising a large-breed dog is more like running a marathon than sprinting to the finish. Patience, observation, and consistency are your best allies.

Every breed has its own growth pattern. An Argentine Mastiff will not develop in the same way as an Irish Wolfhound, so it is important to learn the specific needs of your dog’s breed and adjust your approach accordingly.

With the right food, sensible exercise, and regular veterinary monitoring, you can guide this remarkable transformation with confidence. That way, your future giant gets the strongest possible foundation for a healthy adult life.