In part 1 of this comment together with Jeanine Dunn-Harmon and Wendy Volhard, we started our attempt of answering the question posed in the comment’s title. We decided that in order to live, a dog must eat. How long the dog lives, as well as health, immune system, behavior and temperament, the ability to reproduce successfully and to recover from trauma, all depend on what is eaten. An animal that eats well lives a long life, coping with everyday stresses and strains. One that eats poorly is unhealthy and with age will begin to suffer from chronic diseases. This comment deals with dog food ingredients.Most people have no idea what's in their dog's food. If their dogs pick at the food, people will change to another, trying to find the one just right for their dog. Feeding the correct food to a dog makes the difference between health and disease.Dogs are carnivores, or meat eaters. Their teeth are formed to pull flesh apart, they have simple stomachs and a short digestive tract, ideal for digesting meat. Cereal and vegetable proteins are not as readily digested by the dog. While dogs have adapted somewhat to digesting these proteins, they have to eat in greater quantity of such foods to get the necessary nutrients. More food means more expense, as well as more voluminous stools. Dogs prefer a food high in animal protein, and it makes them healthier and perform better.In order to choose a food that meets the nutritional needs of your dog, you need to understand something about protein, fat, carbohydrates, minerals, vitamins and water. These basic ingredients are the recipe for any food you feed a dog.
Protein, Amino Acids
At the very core of the dog's health and fitness are amino acids. Amino acids are the building blocks of protein and are necessary to life. If you are feeding an un-supplemented food high in cereal and vegetable proteins, chances are that your dog has an animal protein deficiency. Diseases that may result include: Skin and chronic ear infections, reproductive, heart, kidney, liver, bladder, thyroid and adrenal gland malfunctions, some forms of epilepsy, some kinds of cancer, rage syndrome, "spinning," or tail chasing, lethargy, timidity, lack of pigmentation
inability to think and act clearly, lack of appetite, excessive shedding, as well as gastrointestinal upsets.
Protein is composed of amino acids, of which 25 are presently known. Ten or 11, depending on the reference source you use, are essential and cannot be produced by the dog's body; the other 14 or 15 can be converted from the essential amino acids through a chemical chaining process taking place in the liver. These 10 or 11 essential amino acids can be obtained only through what the dog eats, and they must be consumed at the same meal in order to sustain a healthy life.In a commercial dog food, protein is provided by combining animal sources, such as meat byproducts, chicken, cheese, milk, fish, turkey or lamb, together with grain sources, such as corn, wheat, rice, soy and so on. The sum total of these proteins appears on dog food packages as crude protein. How these ingredients are arranged in the recipe and the quantity of those ingredients, whether the animal protein is listed first, third, or fifth, dictates the kind of protein available to the dog.Amino acids are altered by heat, which in turn affects their bio-availability. Dry, semi moist or canned foods go through a heat process in manufacturing, and the finished product can be deficient in amino acids. Such a food, if fed without supplementation, can cause disease. Many amino acids are available only from animal sources, and if grains are the main source, a dog may develop one of the animal protein deficiency diseases listed above. Since amino acids are dependent on one another, a diet that contains too little of one will have a chain reaction effect on the others and will reduce their utilization. To achieve the proper balance, it s necessary to combine foods with the correct amount of amino acids.While the chemical composition of protein is similar for some grains and meat products, the bio availability is different. Soy protein is used as a source of amino acids in food for animals that have complex stomachs, such as cattle and sheep, and as food for pigs, turkey and chickens. Some component parts of soy bind up their own nutrients and make them unavailable to the dog. Young dogs and old dogs cannot utilize the amino acids from soy, hence it should be avoided. Cottonseed meal falls in the same category.The need for amino acids in the diet changes during the different life stages, climate and season changes, trauma or stress. When these stresses are experienced, your dog's food should contain extra animal protein.What are physical signs of deficiencies? By observing your dog carefully, you can pick up signs of amino acid deficiencies. Many will be found on the feet and nails constantly biting or licking feet, crooked nails on one or more of the toes or toenails that are brittle can signal a protein deficiency. Pimples, skin discoloration and crooked whiskers are also deficiency signs. A Landseer Newfoundland we treated for many years had a pimple on the left side of her face in the middle of her whiskers. It was itchy and she would rub her face along the carpet and paw at it, sometimes breaking it open. The whisker coming out of this point was crooked and turned backward. The pimple was situation on the amino acid lysine point. Supplementing the dog's diet with an amino acid complex tablet containing lysine caused the pimple to disappear and the itching stopped.
In summary we come to the conclusion that food proteins are considered complete only when they contain all the essential amino acids. Animal proteins are complete. Vegetable proteins are incomplete and unbalanced, but can be mixed with complete proteins to provide adequate amounts of essential amino acids.
Dietary protein requirements are influenced by various factors. These include digestibility, rate of protein synthesis, carbohydrate and fat levels in the diet and the timing of meals. Clinical factors can influence protein needs of the dog. These include disease, medications and surgery or any other trauma to body tissue.
You can test to see if your dog is deficient in amino acids. If you wish to supplement the dog's diet, test each of the following supplements to see what is best for your dog. Needs change with the seasons, so test several times during the year.
Animal protein supplements: Raw meat, raw liver, cooked meat (lamb, pork or venison), cooked chicken, cooked fish, milk, whole eggs (cooked for 5 minutes, plus shell), yogurt, kefir, cottage cheese, goats' milk, You can add a small amount of any of these proteins to your dog's diet. In total, supplementation should not exceed 10 percent of your dog's total diet.Remember that the inter-dependency of amino acids is such that unless you have a degree in chemistry and understand a fully how the isolated amino acid works, more harm can be done than good. Avoid supplementing with methionine alone if there is a history of liver disease. Too much methionine in relationship to other amino acids can cause coma and even death in dogs that have diseased livers. When supplementing, make sure that the diet contains adequate vitamin C and B complex necessary for protein digestion. Magnesium must be present in the diet for the essential amino acids to work.
Food: What difference does it make? Part 1: Foundation, building blocks, life stage requirements