There's a very rough way of measuring which is %1 to %2 of the dog's total good weight. This means that if a dog is in good shape (almost skinny) and weighs 100lb you'd give it 1lb to 2lb of food per day. However I don't like rules like that because it also depends on how active your dog is. If your dog is having a few days of long hiking for example you'd need to up the amount.
The bottom line is you need to have a mental picture of what your dog looks like in good shape and vary the food according to his condition to always bring him to that good weight. The biggest hurdle for many people is that they don't have this right mental image. After many years of looking at overweight dogs there is a perception that it's the dog's normal condition. When these people see a healthy dog they think it's being starved. This is very prevalent with rottweilers. People think they need to look like a barrel on four sticks. A rott in good condition looks very much like a normal dog especially when it has a tail. I've been stopped on the street by some ignoramus who told my I should feed my dog (rott) more.
The way to do it is start with a smaller quantity than what would be sufficient. Then the dog will lose weight. When it gets to the point where you think it's too skinny you start to increase the quantity.
And by contrast, let's take my dogs and their applications for example....
From the first week of September thru the middle of February, my dogs are hunted 4 days a week . I usually begin trying to bring their weight up towards the end of August . That being said, my black male is a lean dog . He's an American bred field lab and has that build, consequently, he's more efficient in environments where I need him to range a bit and quarter . However, his leaness is evident when the waterfowl season approaches. Waterfowl hunting means alot of time stationary followed by bouts of sometime extreme cold meaning air temps. around 25 F. and water temps right around freezing. Opposing my yellow British female is built like a barrel . Short, stocky, and fat. Comparing the two, I can't keep her out of even the coldest water. She'll get out and break ice just to play while I am putting out decoys whereas Fisher wants none of it, and he is clearly worn by the end of a day of cold water and long retrieves. Again Tenille, can make long retrieves all day long in frigid water, come along into the boat or blind after making retrieves and be ready to hit pheasants that afternoon; although she needs to be kept closer to heel as she's more prone to overheat and I am selective with her sending her into cover that I have either located birds in or suspect there may be .
Full limits both days.
