“Proteins are one of the most important parts of your dog’s complete and balanced diet, along with healthy fats, carbohydrates, vitamins and minerals,” says Dr. Ernie Ward, a certified veterinary food therapist in Ocean Isle Beach, North Carolina. “Proteins are necessary to maintain a dog’s immunity by synthesizing hormones, enzymes and antibodies, to keep the skin and coat healthy, and build strong bones and muscles. Proteins also serve as valuable energy sources to keep your dog bounding all day.”

How Much Protein?

Dr. Ward says, “According to Association of American Feed Control Officials (AAFCO) nutritional guidelines, adult dog food must contain at least 18% crude protein. The majority of dry dog foods sold in the United States. contain about 21 to 27% crude protein. Dogfoods higher than 28% protein have become labeled ‘high-protein,’ although that term has no actual regulatory or medical meaning.”

But what’s the right amount for your dog? Like many things, that depends.

The protein needs of each dog, “varies by individual,” points out Dr. Valerie Parker, an associate professor of Clinical Small Animal Internal Medicine and Nutrition at The Ohio State University in Columbus. “The minimum amount of protein established by AAFCO for canine adult maintenance is 4.5 grams of protein per 100 calo-ries (kcal). Puppies need more; (5.6 g/100 kcal).”

“The amount of protein a dog needs can vary depending on a number of factors like age, level of activity, stage of growth and stress,” adds Johnna Devereaux, CPN, director of nutrition and wellness for Bow Wow Labs, based in Novato, California. “For instance, as dogs age toward their senior years, their need for protein increases in order to fuel muscle and preserve muscle mass. Dogs that also need extra protein include puppies, pregnant or lactating moms and dogs that are healing from injury.”

“Healthy, active dogs can easily handle, and likely benefit from, diets containing 28 to 32% protein,” Dr. Ward says. “This amount of protein, when combined with higher fiber, may also help prevent obesity.”

But there can be too much of a good thing if your dog has certain ailments. “For some health conditions, excess protein can worsen the disease process or make the pet feel worse,” writes Dr. Cailin R. Heinze, a board-certified veterinary nutritionist on Petfoodology, a nutrition blog run by the Cummings School of Veterinary Medicine in Massachusetts. “Two common diseases where this occurs are kidney disease and some types of liver disease.”

Another consideration: Johnna says, “The holistic belief when dealing with dogs with kidney issues is to pay attention to the quality of the protein, which is often overlooked. High-quality, minimally processed protein from animal meat allows phosphorus to bind to other minerals and get excreted through the digestive tract, minimizing the load on the kidneys.”

Does the Source Matter When it Comes to Protein for Dogs?

Speaking of animal meat, it is often the first thing peo­ple think of when it comes to dog food ingredients. “Typically, animal proteins have higher overall protein quality than plant proteins, but even within animal pro­tein sources commonly used in pet foods, there is a lot of variation in protein quality,” Dr. Heinze says. “To maxi­mize protein quality, proteins sourced from both plants and animals may be combined to overcome limitations that the proteins may have independently.”

Johnna adds: “In general, animal protein will always provide the required amino acids and is the best source of protein in the canine diet. With that said, rotating the source of animal protein will help ensure that your dog is getting balanced amounts of the right amino acids; each source of animal protein varies in the quantity of amino acids it provides.” (More on amino acids is below.)

What is Meat Meal?

A common ingredient listed on many dog food labels is not just meat, but meat meal. “Meat meals can be a good source of protein,” Dr. Parker says. “It just means that the water has been removed; it has no bearing on ingredient quality or protein quantity.”

Johnna poses some considerations: “These meals can include tissues from animals that have been deemed unsuitable for human consumption and, though they provide protein, are highly processed. Before feeding a diet with meals, call the manufacturer and find where the meat came from. There are some high-quality food companies that use human-grade dehydrated meat.”

Nonmeat Proteins for Dogs

Some vegetarians and vegans have a hard time feeding their dog animal products. That’s understandable but is often considered a mistake. Consider your dog’s rela­tionship with meat as similar to your relationship with toilet paper — one is a must for each of you but not necessarily both of you.

“It is generally recognized that plant protein sources have lower digestibility than do animal protein sources; however, studies of dogs have found equal total digest­ibility for soy-based protein when the soy product is adequately processed,” according to an article assessing vegetarian diets in the Journal of the American Veterinary Medical Association (JAVMA).

“Pets fed diets containing no animal protein (i.e., vegan diets) or pets fed home-prepared diets that are not carefully designed are at higher risk of becoming deficient in protein or amino acids,” Dr. Heinze cautions.

That doesn’t mean animal proteins are the only ones beneficial to your dog. And plant proteins can help the planet, too. “Protein, especially ani­mal protein, is a resource-intensive industry,” Dr. Heinze points out. “It requires a lot of land, water and food crops to produce. Avoiding excessively high animal protein diets and feeding a comple­mentary mixture of plant and animal proteins can help reduce the environmental burden while ensuring good health for dogs.”

And there’s one vegetarian protein for dogs that really packs a punch. “Eggs have the highest biological value of any protein and are also highly digest­ible,” Johnna says. “Eggs are a great protein source for all dogs, especially those that are ill, because eggs are the easiest protein for the body to process.”

Acid Trips and BVDs (Biological Value Descriptions)

Two critical things to look at when it comes to the protein quality in your dog’s food are the amino acids and BV.

“Amino acids are the building blocks of protein — when an animal eats protein, its body breaks the protein down into these amino acids, which can then be used to build new proteins or be ‘burned’ for energy,” Dr. Heinze explains. “Not all proteins are the same in terms of amino acid types and amounts. The best quality proteins will have the highest amounts of the essential amino acids and will be the easiest for the pet to digest.”

Johnna says, “Of the 22 amino acids, 10 are considered essential to the canine body. When an amino acid is essential it means that the body cannot synthesize it on its own and that it must come from his diet. All dogs regardless of breed, age, etc., require the same 10 essential amino acids.”

AAFCO sets minimum requirements for each amino acid. (See AAFCO’s Minimum Dog Food Protein and Amino Acid Guidelines chart.) The essential 10 amino acids for dogs are Arginine, Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan and Valine.

And now that BVD: “Biological value is based on a protein’s unique combination of amino acids and measures the potential quality of that protein,” Johnna explains. “When a protein contains the proper amino acids, in the proper amounts, it is said to have a high biologic value. Animal protein has a much higher biologic value than most plant protein and it is also easier for the canine to digest; therefore, you should always look to feed your dog a protein with a high biologic value (preferably over 74) as well as one that is highly digestible.”

Every food has a Biological Value. Below are some common ones for dog food ingredients:

• Egg = 100
• Fish meal = 92
• Fish = 88
• Beef = 78
• Chicken = 78
• Soy = 74

Sometimes it seems like there are almost as many different protein sources as there are dogs. “Before you make significant changes to a dog’s diet, always consult with a veterinarian,” Dr. Ward advises. Set up that “meating” soon so you know your dog is getting the best diet possible — and that doesn’t have to mean most expensive.

AAFCO’s Minimum Dog Food Protein and Amino Acid Guidelines

*Calorie content of dog food is expressed as Kilocalories/Kilogram Metabolisable Energy. **Recommended concentrations for maintenance of body weight at an average caloric intake for dogsof a given optimum weight.