I adopted Max when he was almost 8 months old and he weighed 44 lbs and about 22.5 inches. Now he is almost two and he is 74 lbs and right at 25 inches. He has really bulked up. I heard they grow until 2 to 3 years of age. The biggest thing I noticed is how he expanded around the chest, became broad shouldered. Just what I noticed. Good luck with your babes.