The Truth About Byproducts in Pet Food

What are Byproducts?

Few words on the average pet food bag evoke disdain and disgust like the word “byproducts.”  But is the fear and loathing deserved?  What are byproducts, exactly?  The definition published by the American Association of Feed Control Officials (AAFCO) is not particularly helpful:

“Secondary products produced in addition to the principal product.”


This definition is broad and not very useful.  More specific terms are generally used on pet food labels, and the definitions are regulated.

Meat Byproducts

“Meat Byproducts are 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 de-fatted low temperature fatty tissue and stomachs and intestines freed of their contents. It does not include hair, horns, teeth and hoofs.”  Unless the byproducts are derived from cattle, pigs, sheep, or goats, the source must be named.

It’s worth noting that indigestible parts of the animal like hair and hoofs are not included in this definition.  Although some ingredients, such as lungs and udders, are not considered “edible” for human consumption by the USDA, these types of meat may be very appetizing for dogs and cats.  Remember, that this definition of “edible” is based on US standards of consumption.  People in other countries often make use of these ingredients in their food, and some are considered delicacies.

Poultry Byproducts

Unlike meat byproducts, poultry byproducts may contain the head and feet.

Meat Meal

Meat meal is rendered, or cooked, to destroy any harmful bacteria, and it is finely ground.  Like meat byproducts, it does not include bone, intestinal or rumen contents, hoofs, teeth, or hair.  Meat meal does not contain added blood.  Unlike meat byproducts, manufacturers do not have to specify the species from which the meal is made.

Meat and Bone Meal

Meat and bone meal is similar to meat meal, but bones are included.  Bone meal may be added to increase the calcium content of a food.

Animal and Poultry Byproduct Meal

These are rendered animal or poultry byproducts and do not contain hair, feathers, hoofs, or teeth.

The choice to feed pet food containing byproducts or not may be based on personal aesthetics.  It shouldn’t be based on fear.  Byproducts in pet food can add valuable nutrients.  And using byproducts in pet food reduces waste by making use of parts of slaughtered animals that would otherwise be discarded.

Learn more.


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