Different dogs require different amounts of protein, depending on their age, their size, and their energy needs. An active puppy will require a different amount of protein from a sedentary adult dog or from a canine athlete. The amount of protein required may also depend on the quality of protein an individual dog takes in.
On the average, puppies require a minimum of 28 percent protein per dry weight in their food. Small-breed puppies and their mixes have tiny stomachs and are at risk of hypoglycemia. They need a greater percentage of protein per cup of food than larger-breed puppies of the same age. Large-breed puppies fed protein in amounts exceeding the recommendation may grow too quickly and suffer bone and joint problems as they mature.
Most adult dogs have only moderate energy requirements. Because they are no longer growing and do not need to perform a lot of muscular repair or development, they require only about 18 percent protein in their food. However, adult dogs require at least this amount to maintain themselves in good repair and good health. Lower amounts of protein are recommended only for dogs with illnesses that prevent them from metabolizing normal amounts of protein.
Dogs with Special Needs
Canine athletes, often called performance dogs, as well as working dogs, need higher amounts of protein to maintain their muscles and repair wear. These dogs can require between 25 and 35 percent protein in their food. Female dogs nursing a litter also require 28 percent or more protein. Elderly dogs may require lower protein percentages if they have kidney or liver damage. However, senior dogs in otherwise good health may require a higher protein content in their food because their bodies must work harder to digest.
Not all proteins are created equal. The source of the protein and its digestibility affect a dog's ability to use that protein effectively. Ingredients are listed in descending order of weight on the food label; manufacturers don't specify digestibility, but a food that places meat high on its list of ingredients will contain more usable protein that foods that do not, or that list such ingredients as "meat and bone meal." Carbohydrate-based proteins are not as digestible. A meat meal from which liquid has been removed provides more protein that a liquid-based meat meal.
It is widely believed that feeding dogs too much protein will result in kidney damage. This belief has been proven untrue. Excess protein is excreted by a healthy dog. Large amounts of protein in dog food have also been accused of making dogs hyperactive; however, no evidence supports this claim.