I have a Newfoundland Black Lab Mix puppy. He is almost 6 months old. He weighs about 65 pounds. His father weighed about 130 and his mother 80. How big can I expect him to get?

Comparing him to my Lab puppies I would say 75-80 pounds at the current body condition. Many 90 pound Labs should be 75-80 pound Labs. You should do 2 things now. If you are still feeding a puppy chow, even a large breed one, switch him to an adult chow. An early switch to adult chow slows growth and allows more time to develop sturdy joints. Also go to http://www.puppychow.com/products/po...condition.aspx Adjust how much you are feeding to bring him into the ideal body condition. After genetics, keeping the dog lean and avoiding an excessively rich diet are the 2 most important things in avoiding hip and other joint problems.