By Yvonne McGehee, from the July 2005 Newsletter

Taking up where we left off in the last issue, I'll present background for understanding diets presented in books to be reviewed in the next issues.

It is often heard that people can't feed their dogs a homemade diet because it won't, or can't, be "complete and balanced.” Sometimes people ask if the homemade diets have been analyzed. Some books give analyzed diets, while others include diets that are not analyzed, such as most of us eat. Not all analyses are the same, and there are limits to what an analyzed diet really means.

Diets can be analyzed on paper, meaning the contents of the ingredients according to the USDA nutrients in foods database are calculated on paper and compared to the NRC (National Research Council) list of known Nutrient Requirements of Dogs. The NRC requirements are derived from feeding trials in which nutrient levels at which deficiency diseases, or occasionally diseases of excess, develop are determined.

On-paper analysis has limitations because in real life, nutrients interact with other nutrients, affecting absorption and utilization. Without feeding trials, it's difficult to know exactly what those interactions will be once the food is in the animal. Diet contents can be analyzed directly by chemical techniques, which is expensive and beyond the scope of most authors, and which, though more accurate at telling exactly what is in the food than an on-paper calculation, still doesn't tell how the live animal actually utilizes the food.

Many pet food manufacturers do not conduct feeding trials, but use on-paper analysis and add excess nutrients in hopes that any adverse nutrient interactions will be overcome and enough of everything will be present to prevent deficiencies as the animal's body utilizes the food.

To overcome the deficits in paper-based analysis, some pet food manufacturers conduct feeding trials. The feeding trials required for AAFCO certification (Association of American Feed Control Officials) are short in duration (6 months or less depending on the specific trial), require very few animals (under 10), and have limited requirements, such as mortality not above a certain percentage and weight maintained within certain parameters.

They demonstrate that the diets tested are life sustaining for a limited period of time, but do not show that they are life-optimizing for long-term use. They provide no information on effects of long-term use in the development of obesity, diabetes, arthritis, or heart, kidney, or liver disease. Because there is no prospect of making money through homemade diets, they are not used as controls for feeding trials of processed foods, nor are they researched.

Some commercial dog food manufacturers conduct feeding trials including detailed analysis of how the diet is actually digested and utilized by the animal. These are above and beyond the feeding trials required for AAFCO certification. Sometimes they are in response to problems, such as developmental joint disease in large breed puppies fed standard puppy foods, or blindness in cats caused by taurine deficiency in commercial cat foods.

These problems arose in analyzed diets claimed by their makers to be "complete and balanced," and show that there are limits to what "complete and balanced" and "analyzed" really mean. All forms of analysis, whether on paper or through feeding trials, rely on requirements derived from how real animals responded to specific diets, mostly through trials to determine the minimum requirements for specific nutrients to prevent deficiency.

So, if a dog is fed a homemade diet and the dog thrives, this in a sense goes back to the basis from which all analyses are derived. Though being officially "complete and balanced" is probably an illusion at best, as evidenced by constant changes and corrections made to products within the pet food industry itself, a diet can certainly be inadequate, or excessive, or far out of balance. Next time we'll go over books that will help you learn how to feed a healthy homemade diet.

Yvonne McGehee has been breeding elegant borzoi dogs for the past 30 years. She feeds them a fresh food diet. See them at http://personal.palouse.net/valeska.

Copyright: Copyright on articles and recipes are jointly held by the Moscow Food Co-op and the respective authors, except were otherwise noted.

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