Pet foods can be classified into three main categories: premium, supermarket brands and other. In pet foods you truly get what you pay for.
Premium brands of foods include Science Diet in Growth, Maintenance, Senior and Light formulas, Iams Eukanuba, Purina’s One and ProPlan and Nature’s Recipe.
Premium diets are characterized by higher quality and digestibility of nutrients, higher caloric density (feed less to get the same nutrition) and a slightly higher price per pound, though the price per feeding may be no more since you feed less. In canned and dry forms, they are usually carried in veterinarian’s offices and pet stores. They are intended for those pet owners who want the very best in nutrition for their pets for the entire life cycle from growth to old age. These folks are not “health food nuts”, but they realize that our pets, like us, are what they eat.
Good supermarket brands include Purina (in all its forms, look for the checkerboard squares), Gaines and Alpo in dry forms and Kal Kan and Ken-L-Ration in canned foods. Avoid the high protein foods unless your pet is pregnant, nursing, healing from illness or surgery or working very hard. The extra, wasted protein can be hard on the liver and kidneys as well as your pocketbook. Dry foods are better for your pet’s teeth, and are less calorie-dense, helping to control your pet’s weight.
Other. People get suckered into buying “other” because of the crude analysis on the label. “But, Doc, its got 41% protein!” That statement is based on the panel on the back of the package headlined “Crude Analysis.” Let me tell you how crude analysis is performed.
To determine crude protein, the food sample is vaporized for nitrogen content and multiplied by a conversion factor. Mineral content, listed as “ash” is determined by burning the sample. What’s left is “ash”. Crude energy is the amount of energy given off during the burning. “Carbohydrate” is listed as NFE (nitrogen-free-extract), in other words, whatever is left that’s not crude protein, fat or ash.
Let’s design a good quality canned dog food with a desirable crude analysis of: Crude Protein-10%, Crude Fat-6.5%, Crude Fiber-2.4%, Ash-4.3%, NFE-18.8% and Moisture-68%. Sounds good and compares favorably with the Science Diet you paid a dollar a can for, right?
Wrong! You can make a formula test out to this analysis with four leather work shoes, a gallon of used crankcase oil, a pail of crushed coal and 68 pounds of water. The label would impress an uninformed buyer, but it wouldn’t nourish his dog.
Crude Analysis has long outlived its usefulness, but, sadly, is still required by the FDA on every bag and can of pet food sold in the U.S.