A giant-breed puppy is building a large, heavy frame on joints that are still soft at their growing ends, and that mismatch is the whole issue. His growth plates, the areas of developing tissue near the ends of long bones, stay open far longer than a small breed's, and during those months excess weight, over-rich feeding, and high-impact exercise can all load joints that are not yet built to carry them. Protecting him is not about wrapping him in cotton wool. It is about growing him slowly, keeping him lean, and choosing exercise that builds muscle without pounding developing legs.
Why giant puppies are different
Owners are often surprised that the goal is deliberately slower growth, not maximum size as fast as possible. A puppy who gains weight too quickly puts adult-level strain through immature joints every time he runs, lands, or twists in play. You should be able to feel his ribs easily under a thin covering and see a waist from above and from the side; if you cannot, talk to your vet about adjusting food before the next growth spurt rather than after it. Regular weigh-ins during the first eighteen months catch a creeping growth curve early, when a modest feeding adjustment is all that is needed to correct it.
Feeding for slow, steady growth
Choose a food formulated specifically for large and giant breed puppies, because those diets are balanced for controlled growth, including a careful calcium level; adding extra calcium or rich supplements on top can do harm in this group, so do not supplement unless your vet advises it for a specific reason. Measure meals rather than estimating, split the daily amount across set meals, and adjust by body condition rather than by appetite, since a giant puppy's enthusiasm for food is no guide to his needs. Keep treats as a small part of the day and count them honestly. At each vet visit, review the growth chart together and agree the next adjustment before you leave.
Exercise and everyday handling that spare joints
Build fitness from frequent short walks and free play on grass or other forgiving, grippy ground, and let him set the pace rather than jogging him beside you or walking him for long distances on hard pavement. Avoid repetitive stair climbing, jumping down from cars, sofas, and beds, and slippery floors where legs splay; a ramp or a lifted unload is kinder than a leap he will attempt happily without understanding the cost. Wrestling with much heavier adult dogs and endless ball chasing with sharp turns are also worth limiting while he grows. Stop play while he is still keen rather than exhausted, because tired puppies move clumsily and injure more easily.
Joint protection can feel restrictive, but the payoff is an adult dog whose hips, elbows, and shoulders had the chance to form properly under sensible loads. Most of the routine is simply consistent: measured food, lean condition, sensible surfaces, no heroic exercise. Keeping his weigh-in results, food plan, and vet growth reviews together in KinsLe's Pet Passport makes that consistency easy to hold across the whole household, so the puppy gets the same careful handling on busy days as on quiet ones.