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Commentary: Why By-Products in Dog Food Aren’t Always a Bad Thing

By-products, such as liver and other animal parts, in pet food get a bad rap that isn't always deserved.

Dr. Marty Becker  |  Apr 5th 2017


By-products: They’re what’s for dinner. At least if you’re a dog or cat, although my wife, Teresa, and I have been to some pretty fancy restaurants that served what many people would consider by-products. Thymus gland, anyone? (Better known as sweetbreads.)

Pet food ingredients and pet nutrition in general can be confusing for many, but by-products get a bad rap that’s not always deserved. Let’s chew on the subject to find out more about them.

Dr. Marty Becker

Dr. Marty Becker

First, what are the by-products that are used in pet food? They’re not feathers and beaks. By-products are the co-product of food ingredients, including portions of an animal that are less commonly used in the U.S. human food supply but can provide essential nutritional benefits. Some examples of by-products include clean animal parts like the liver, kidneys, heart, lungs, spleen, corn gluten meal and tallow. Doesn’t sound that different from what you’d see African wild dogs eating on Nat Geo WILD.

I’ll be the first to say that some of those things don’t seem appetizing to the human palate. However, by-products are incredibly nutrient-dense and highly palatable to animals. In fact, cats and dogs in the wild instinctively eat these organs first because they include a wealth of nutrients such as protein, healthy fats, vitamins and minerals. So it’s not a bad thing to feed by-products in your pet food so long as it is part of a complete and balanced diet.

I asked my colleague Dr. Tony Buffington, a veterinary nutritionist, if by-products have any benefits for pets. Here’s what he had to say.

“Properly produced by-products can provide a wide range of essential nutrients for pets and can be a safe and economical use of biological material.”

That’s a benefit to both humans and other animals, he notes.

Now, depending on the source and the processing, the nutrient content of by-products isn’t always reliable. Poor processing can allow by-products to become contaminated. Improper processing can also result in less availability of nutrients. That’s why it’s important to know the manufacturer’s reputation.

Pet owners can ensure their pet’s food is safe and healthy, whether it includes by-products or not, by checking to make sure manufacturers meet or exceed FDA and AAFCO standards. For example, go directly to a manufacturer’s website to learn more about what safety and quality standards a company employs, such as testing raw materials for impurities and nutrient content, or working with food scientists, veterinary professions and nutritionists to develop products. Any meat and poultry by-products from farm animals should originate at facilities certified by the USDA or an equivalent authority.

“Avoiding all these potential problems is the responsibility of pet food manufacturers using by-products,” Dr. Buffington says. “Their success depends on the vigilance and integrity of the company.”

In general, pet owners should research the quality and safety standards of the company that makes their pet food. It’s important to know who makes your pet’s food, where it’s made and what steps the manufacturer takes to ensure the quality and safety of the food. Here are a few tips on how to do exactly that:

  • Look beyond the ingredient list on the package and check the quality of the manufacturing as well as how stringent the quality standards are of the company making the food.
  • Go to your pet food manufacturer’s website. See if it owns the factories, if the food os made in the United States, and what steps it takes to ensure the pet foods meet or exceed FDA and AAFCO standards for safety and quality.
  • Call your pet food manufacturer and ask about its manufacturing process, the quality and safety standards, and the ingredients used in the foods. You should be able to learn why it uses any ingredient and the nutritional benefits.
  • Talk to your veterinarian. They should understand pet food nutrition and be able to provide recommendations on pet foods that are safe and healthy for your pets.

About the author: Dr. Marty Becker, “America’s Veterinarian,” has spent his life working toward better health for pets and the people who love them. He is the founder of Fear FreeSM and was the resident veterinary contributor on Good Morning America for 17 years. He is a founding member of Core Team Oz for The Dr. Oz Show, and a member of the Dr. Oz Medical Advisory Panel. He has written 25 books that have sold almost 8 million copies, including three New York Times best-sellers — one of which is the fastest-selling pet book of all time, Chicken Soup for the Pet-Lovers Soul. He has been a contributor to Parade magazine, Reader’s Digest and AARP.com. Animal Radio hosts him monthly as their Chief Veterinary Correspondent. Dr. Becker is an adjunct professor at his alma mater, the Washington State University College of Veterinary Medicine, and also at the Colleges of Veterinary Medicine at both Colorado State University and the University of Missouri. Additionally, he has lectured at every veterinary school in the United States, and is on the advisory board of World Vets, an international veterinary and disaster relief programs to help animals. He practices at North Idaho Animal Hospital because he loves veterinary medicine, pets and the people who care for them. Connect with him on Facebook and on Twitter at @DrMartyBecker.