Lab mix and over-exercise

Question
Hi,  I recently got a 4-month-old lab mix puppy (now almost 5 months and not yet spayed).  (She is part chow and maybe something else, but appears mostly lab and seems to have a lab temperment.) She really enjoys long romps in the snow; but now I am wondering if I may be allowing her to exercise too much.  Should I be concerned that her jumping through deep snow might cause hip dyplasia?  She seems indefatigable and never acts tired.  Should I still limit snowshoe and cross-country ski adventures with her?    Thanks, Elizabeth

Answer
Even the most intensive exercise won't cause hip dysplasia, it is mostly a matter of genetics and diet.  It can lead to soft tissue injuries.  How much is too much is harder to say.  Do not push her too much.  When you see her energy flagging, quit.  At least take a break before turing back.  When they are smaller, I often carry a puppy for a ways to give it a break, sometimes even under my coat.  

Take it easy, keep her lean, and switch to an adult chow now.  That will slow her growth, giving her joints more time to develop.