German Shepherd Q&A
Most large breed dogs reach their top height by 18 months of age. They don't normally put on the weight they will be until 3 years of age.
My male Mastiff reached his mean weight of 170lbs at about 18 months, he will be 4yrs in july. He is in perfect height/weight proportion and is still quite active and playful. I am hoping this may be a blessing in disguise, perhaps extending his life span a year or two
Ours was fully grown at about 2 years old but he filled out until he was 3. He probably put on an additional 20 pounds as he got more massive and thick.They are the best dogs.