Canine Digestive System
Much of the marketing hype surrounding high end dog food today stresses that dogs evolved from wolves and therefore should have the same diet. Dogs have evolved with humans for at least 10,000 years and have gone through significant physiological changes and nutrient requirements during that time. For the first 9,850 years, dogs were fed scraps from whatever was left over from around the camp fire or around the house. It wasn’t until about 150 years ago that commercial dog foods became available. Early foods left a lot to be desired and truly high quality dog foods did not appear until about 30 years ago.
The digestive system of dogs has evolved to be able to digest cooked grains and vegetables and dogs receive substantial nutritional benefit from these products. The average pet dog needs about 23-25% protein and there is little independent scientific evidence as to whether dogs can benefit from protein levels over 35% that are often seen in no grain formulas. Some experts have contended that high protein diets are even detrimental as excess protein must be excreted by the animal thereby taxing the renal system. Dogs are omnivores (as opposed to cats which are obligate carnivores) and their digestive systems are designed to obtain nutrition from both meat and cooked grains and vegetables. Even wolves, when they take down a deer or elk will eat the guts first. Why? Because a wolf cannot digest raw grass but lets the herbivore handle the digestion. The wolf can then benefit from the nutrients provided by the digested plant matter. Cooking during the dog food production process provides an effect similar (and far more palatable at least to humans) to the herbivores digestive tract which makes the nutrients from plant matter available to canines.
If you are interested in reading more about canine (and feline) nutrition we recommend Feed Your Pet Right by Marion Nestle and Malden C. Nesheim. This book does a great job of explaining pet nutrition and cuts through many of the inaccuracies often contained in internet sites. This book is available at the Bend Public Library as well as many bookstores. A far more difficult (but extremely informative) read is Nutrient Requirements of Dogs and Cats by the National Research Council (part of the National Academy of Sciences). A copy is available through the Bend Public Library via the interlibrary loan program (the copy is kept at Oregon State). This very academic tome is also available for purchase on-line, but at a cost of $400 per copy.