Nutritional Value of Cooked Meat??

[OC_Spirit]

I'm just wondering if anybody would happen to know what the nutritional value of beef cooked at 350F for 7hrs would be in comparison to raw??? Would such a long cooking time leash all the good nutrients out?? I have access to as much of this stuff as I want. They cook the beef "heels" (as in the cut of meat that is located right beside the eye of round) and use the resulting juice to make gravy and have no need for the meat itself. I am just wondering if it is worth anything to the dogs to feed in winter, or if after such a long cooking time it is nothing much more than a "filler". If the latter I would feed in the summer time only...