Chocolate Lab/German Short-Haired Pointer Mix

Question
Hi, I volunteer with the Humane Society and recently rescued a Momma and her 8 pups. All the pups %26 Momma were adopted out. I ended up keeping one of the pups, a chocolate lab (very fluffy, he looks like a Chesapeake Retriever).  I have always heard to keep labs on puppy food for 2 years (not sure where I heard that from).  He is currently on Castor %26 Pollux Natural Ultramix Puppy Formula.  Should I only keep him on puppy food until he is 4 months?  He will be 10 weeks on 12/30/09 and weighs about 18 lbs already (he is very stout).  Just need some advice :)  I have never had a puppy - always adopted older dogs.  Thanks in advance!

Answer
Puppy chow is formulated for fast growth, faster than is best for developing large breed puppies' joints.  It is also highly profitable for the dog food companies and retailers.  Many people repeat what the dog food companies say.  

You should be feeding a puppy chow now. Switching to an adult chow for the larger breeds at 4 months, slows growth and helps develop sturdier joints.  This is a very common practice among the service dog schools that know more about producing large breeds with a long, active life.  Other better informed people are doing likewise.  

For the same reason, it is very important to keep the the puppy lean unlike typical puppies.  Your dog definitely should be narrower at the waist than the hips and chest. You should be able to easily feel the ribs, but not see them. Each dog is different. Standard recommendations are a good place to start, but each dog must have its food and exercise adjusted to its individual needs. Here is a link to a good illustrated guide, http://www.longliveyourdog.com/twoplus/RateYourDog.aspx

Shepherds often refuse to eat enough to keep their ribs hidden completely.  Labs are more likely to eat more than is good for them and look for more.