By: Melissa Grosjean

Protein is arguably the most important component of your dog, and is often the most hotly debated aspect of pet foods. What is the best source of protein for dogs? How much protein should be in the diet and can you feed too much of it? How can you tell which foods have better protein sources? What about pets with food allergies? It’s a lot to ponder and leaves many guardians frustrated and confused about which of the seemingly endless variety of pet foods they should feed their companion.

During the last 5 to 10 years the rapid growth of the natural pet foods market has significantly expanded the viable feeding options for responsible pet owners, but having more choices does not generally make a decision easier. On the contrary, the more options available, the more difficult the choice becomes. In this article, we will help make that decision a little easier for you by discussing one of the key factors influencing pet food evaluation – proteins.

Evaluating Protein Sources

A protein molecule is made up of chains of amino acids. Different sources of protein contain different combinations of the 22 or so amino acids. Of these amino acids, 10 are considered “essential” amino acids; because dogs and cats cannot make them on their own, these particular amino acids must be present in the diet. When a dog or cat consumes protein, it gets broken down during the digestive process into its individual amino acids. Those amino acids are then reassembled into the building blocks of body tissues such as skin, hair, muscles, and organs. Amino acids are also utilized to produce metabolic enzymes that are necessary for many bodily functions including the regulation of antibodies within the immune system and the transfer of nerve impulses.

Protein from animal sources contains the most complete and most easily digested and assimilated amino acids for dogs and cats. Animal proteins are not only more bio-available and contain a wider array of amino acids – both essential on non-essential, they are also more palatable for you companion. The biological value of a protein is determined by how readily the amino acids broken down and used by the body. For dogs and cats, egg whites are at the top of the list with a biological value of 100, followed by muscle meat (beef, chicken, lamb) at 92, and organ meats at 90. Wheat and corn are way down the list with biological values of 60 and 54. Cooking meat at the high temperatures required for canned foods and kibble reduces it’s biological value, providing another reason to include raw or less processed foods in your companion’s diet such as freeze dried or dehydrated meals.

When evaluating the protein source on a bag of kibble, keep in mind that whole meats, such as an ingredient listed as “chicken” or “beef,” contain 75% water. So if a whole meat is listed first, the next ingredient should be a specific meat meal to insure the protein in the food is from animal sources, not grains (i.e. chicken meal or beef meal, not generic “meat meal” or by-product meals). The top-quality pet foods on the market use USDA sources (human grade) for their meat meals. If the ingredient lists “chicken” first followed by grains or grain by-products, you can be sure that much of the protein in the food comes from the grains and is less bio-available to your pet. Trying to force carnivores to derive their amino acid requirements from grain sources is one of the main contributors to the pet obesity epidemic facing our dogs and cats today.

Which Meat is Best?

Is beef best for dogs, or is lamb better? Is chicken the best protein for cats? While there are strong opinions among pet enthusiasts about the answers to those questions, the real answer is – it completely depends on your individual cat or dog. Some research, specifically that of William Cusick, suggests that dogs do better on a diet and protein source that most closely matches that of their ancestors: the food that was available in the region in which the breed developed. For example: Border Collies would eat lamb, fish and poultry as they originated in Scotland where these were staples in the diet. The Greyhound, originating in Egypt, would eat rabbit, pork, poultry and goat. German Shepherds would be fed beef, as they were originally bred in the Alsation Region of Germany.

While breed specific guidelines may be helpful for some dogs, for many dogs their heritage is quite unknown. For another large group of dogs (and cats), food allergies will determine which protein sources are best. Cats on the other hand, are assumed to have all developed on a similar diet of rodents – specifically mice, birds and the occasional rabbit. So which meat is best? In the absence of food sensitivities or allergies, the answer is “at least three different ones.” Rotation insures a broader nutritional base over time and helps reduce the incidence of food sensitivities and allergies. Many dogs and cats fed the same food for years on end will develop signs of intolerance such as itchy skin or paws, or chronic digestive problems such as gas, loose stools or frequent vomiting. Rotating between at least three or four different foods with different protein sources, and preferably from a variety of manufactures, provides the ideal answer to “Which food is THE best for my companion.” Only you and your companion can really determine what is best by trying various high-quality foods and choosing those that your dog or cat thrives on.