Welcome, feline friends! Skye Blake, your intrepid detective, here to uncover answers to a curious question… are meat by products bad?
And what the heck is a by product anyway?
The information here is for general knowledge… always see your vet with questions about your cat’s individual needs.
Who Is Skye Blake?
Skye Blake, Cat Info Detective, is a curious cat researcher (not a veterinarian) who sniffs out expert, reliable sources about cats, studies their information, then passes it on to you!
Sometimes there’s not enough evidence for easy answers, so Skye gives you all sides, explains the situation as thoroughly and clearly as possible, and links you to experts on each page.
All sources are at the bottom of each page so you can do more snooping.
What is a By-Product?
“A by-product is something produced in the making of something else.” 1 “By products and pet food, Animal Health Services of Cave Creek”, March 12, 2011
This a very broad, generic term that can apply to many things.
In cat food terms, one meaning is any edible or inedible part of an animal left after it’s been slaughtered for human food.
Leather and horns are good examples of useful inedible by products.
In the world of pet food, manufacturers use “by product” as an umbrella term to describe ingredients that aren’t listed separately.
“Meat by products” come only from mammals like beef, lamb, rabbit, or kangaroo.
“By products” come from other things like fowl (chicken, turkey, duck) or plants like wheat, corn or soy.
Why Do People Think By Products Are Bad?
The term “by product” has become synonymous for many people with horrible, dangerous, and offensive ingredients, in both human and pet food.
Some people feel that any food containing by products is automatically bad and should be rejected.
But is this true? Are all by products always bad?
In the past, “by product” has been used as a cover for unethical pet food companies to include inferior, diseased and tainted animal parts, including pets that had been euthanized and inedible parts.
This created a reputation that companies simply throw anything toxic or unhealthy into pet foods as fillers, including roadkill.
In the U.S., it’s illegal for pet food manufacturers to use meat by products from any animals not properly slaughtered for food.
What Are Good By Products?
In the United States there are always by products in pet food even if the word isn’t on the label.
Good by products are those that provide the nutrients your cat needs in a highly digestible form that taste great too!
Meat by products are what most people think of in cat food, but there are other useful types.
Some examples are vitamin E tocopherol, a by product of soybean production, and vegetable oils, like sesame, corn or soy that are by products of edible seed processing.
Meat by products are things like beef liver, stomach, testicles, heart, and other organs that are nutrient-rich.
Typically, they’re made into meal, then added to the pet food during processing.
They’re just as important as muscle meat… in fact, many organ meats are more desirable for their vitamins and other nutrients.
They’re very digestible, which is important for “bioavailability”, the ability for the nutrients to absorb into the body.
Don’t forget, cats who hunt their food eat the entire animal, including the organs many people think are gross!
In many parts of the world, organ meats like heart, tripe, tongue, and even testicles are delicacies.
Reputable pet food companies have high quality and safety standards and require the same from their product suppliers, including by products.
This includes making sure the products aren’t excessively high in minerals and ash, which can happen if they have too much ground bone.
This is important for avoiding nutritional issues, such as bladder stones from too much calcium.
More For the Curious!
Curious about more cat food topics? Take a look at “Cat Food!“
If you’d like some detailed, in-depth information about animal by products, this video, recorded by a professor in India, explains what by products are in pet food, how they’re processed and their uses.
The information is specifically about the European Union but is similar to processing methods used in the United States.
There may be some differences in legal requirements for by products in the U.S. since the pet food industry is highly regulated.
Sources used on this website are either primary or secondary.
Primary sources are always preferable and have the most reliable information because they’re original and directly referenced.
Scientific abstracts and data are good examples of primary sources.
Secondary sources are weaker because they usually consist of opinions or articles that give no sources of their own. Sometimes they refer to primary sources.
When I use secondary sources, most are those with some authority, such as veterinarian or cat behaviorist books and articles.
List of Sources
“6 Things Your Vet Wants You to Know About Cat Food “, by Amanda MacMillan, Reviewed by Amy Flowers, DVM, April 01, 2018, webmd.com
“18 Different Types of Cat Food: What’s Best for Your Cat?“, Excited Cats
“About AMS | Agricultural Marketing Service” (usda.gov)
“The Association of American Feed Control Officials” (aafco.org)
“By Products and Pet Foods“, Hills®
“Canned or Dry Food: Which is Better for Cats?”, Skeptvet (skeptvet.com)
“Do Cats Need Wet Food? – How to Choose a Wet Cat Food” by Emily Drew, PetMag.com, February 12, 2021
“FDA’s Regulation of Pet Food“, FDA.gov
“How-Pet-Food-is-Made.pdf“, Pet Food Institute (petfoodinstitute.org)
“How pet food is made – making, used, processing, parts, components, product, industry, machine“, How Products Are Made (madehow.com)
“Is wet food bad for cats? A vet’s view“, PetsRadar
“Pet Food“, FDA
“Questions & Answers: Contaminants in Pet Food“, FDA, July 29, 2021
“Raw, Refrigerated, and Dry Pet Foods“, Anasazi Animal Clinic (anasazivet.com), January 25, 2022
“Wet vs. Dry Cat Food, or Both?”, by Cathy Meeks, MS, DVM, DACVIM, PetMD.com, January 19, 2021
Updated November 15, 2023