Why By-Products are Good for Your Dog

There is a lot of conflicting information and discussion currently about meat by-products in dog food. Many pet food companies boast that their diets don’t contain by-products and therefore are superior.

Much of this hype is actually a marketing gimmick. Meat by-products are not only an environmentally sustainable ingredient, by-products are a great source of nutrients.

Many dog owners aren’t even sure what ‘by-products’ are, and are even less sure about what type of nutrition they provide. This article will explain what by-products in dog food are, and illustrate how they are a healthy part of a balanced canine diet.

Humans Eat By-products

It is untrue that by-products are the leftover unwanted animal parts. They absolutely do not contain hair, feathers, hooves, etc.

The Association of American Feed Control Officials (AAFCO) regulates the dog food industry and defines meat by-products as “the non-rendered, clean parts, other than meat, derived from slaughtered mammals. It includes, but is not limited to, lungs, spleen, kidneys, brain, livers, blood, bone partially defatted fatty tissue, and stomachs and intestines freed of their contents. It does not include hair, horns, teeth and hooves.

Nutritionally sound dog food diets require concentrated, highly digestible ingredients in order to provide nutrients for optimal health. By-products can deliver this.

It is estimated that between 25% and 40% of dry matter in diets considered premium is meat by-products, and research supports that by-products are highly digestible and nutritious (1, 2, 3).

Meat by-products are widely consumed by people around the world, and have been for centuries. Many cultures consider meat by-products as delicacies (4). It is simply not true that by-products are inedible and should be considered waste (3).

Extremely High in Nutrients

While meat from muscle tissue is rich in protein, it is relatively deficient in vitamins and minerals. Diets that rely heavily on skeletal muscle will end up having to add vitamins and minerals in the form of manufactured ingredients or from other sources in order to be balanced.

Meat by-products differ in their amino-acid composition from skeletal muscle, providing varied nutrients not found in traditional meat. Vitamin content is typically higher (5).

For example, kidney and liver contain the large amounts of riboflavin, a B vitamin that acts as a coenzyme, important for many of the dog’s body functions. A diet lacking in riboflavin can lead to stunted growth in dogs, skin issues and weakness.

Liver is extremely vitamin-rich and contains the most niacin, B vitamins and vitamin A of all the meat by-products. A single 100g serving of beef liver provides 4 to 10 times the recommended daily allowance of vitamin A for a human (5).

Vitamin A is necessary for growth, bone and teeth development, immune system function, skin health, and for maintaining vision. Dogs with diets lacking in vitamin A are prone to skin disorders and disease of the eye, including retinopathies and corneal dysfunction (6, 7, 8).

Mammal spleen and lungs, a meat by-product found in dog food, is a rich source of iron. Iron, of course, is necessary for many of the dog’s body functions. Iron forms the hemoglobin in red blood cells which carries oxygen to the body’s tissues. A lack of iron causes weakness, anemia (low red blood cell numbers) and a fast heart rate in dogs (9, 10).

Bone and bone meal are rich sources of calcium and phosphorus. These minerals are essential for healthy bone growth in puppies and important for maintaining bone health in adult dogs (11, 12, 13).

Many organ meats contain a higher amount of polyunsaturated and monounsaturated fatty acids than lean tissue. Diets rich in unsaturated fats have been shown to be healthier than those rich in saturated fats which are associated with obesity (14, 15, 16).

While dogs don’t suffer as much cardiac disease related to obesity as humans do, studies have shown that obesity in dogs translates to a decrease in lifespan by about 2 years. Obesity is related to a slew of diseases, including osteoarthritis, diabetes, and orthopedic injuries, to name a few (17, 18, 19).


Another wonderful argument for the benefits of meat by-products in dog food is the fact that they are a part of an environmentally and financially responsible agricultural system (3, 20).

By using all the parts of the animal, dog food manufacturers are not competing with the human food chain and are lowering overall cost to farmers while reducing waste. Sustainable agriculture is benefited by the use of meat by-products in dog food (3, 20).

Closer to Ancestral Diet

A popular current marketing trend in dog food is to claim that the diet is true to ancestral canine roots. “It’s what they eat in the wild.” Using this argument makes meat by-products even more relevant.

Wild dogs will typically eat the whole carcass, often preferring the organ meats, as they are rich source of nutrients and are palatable. In this way wild canines are able to obtain the vitamins and minerals needed for survival, whereas a diet of only lean meat would be deficient.


In conclusion, meat by-products are a nutritionally sound ingredient in dog foods. They provide a plethora of vitamins, minerals and nutrients while being part of a sustainable agricultural program.

Their presence in dog food is in no way a detriment to the diet, and in fact, the opposite is true. A better indicator of a quality diet is where the ingredients are sourced, and the manufacturer’s reputation.

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