Common Sources of Protein in Pet Food

140812 Dog and Cat

In our post Dog and Cat Food Macronutrients: Protein Part 1,  we started our discussion of Protein, the foundation for a quality pet food.  Today we will examine the common pet food proteins – real meat, meal, and by products.

The Association of American Feed Control Officials (AAFCO) has created standard definitions of some commonly used pet food proteins. Some of these definitions are listed below.  Generally speaking, these definitions are not very ‘appetizing’, but suffice it to say that the more processed and less specific the protein source, the less appealing it is.

  • Beef – is the clean flesh derived from slaughtered cattle, and is limited to that part of the striate muscle which is skeletal or that which is found in the tongue, diaphragm, heart, or esophagus; with or without the accompanying and overlying fat and the portions of the skin, sinew, nerve and blood vessels which normally accompany the flesh.

  • Chicken – the clean combination of flesh and skin with or without accompanying bone, derived from the parts or whole carcasses of chicken or a combination thereof, exclusive of feathers, heads, feet and entrails.

  • Lamb Meal – the rendered product from lamb tissues, exclusive of blood, hair, hoof, horn, hide trimmings, manure, stomach and rumen contents except in such amounts as may occur unavoidably in good processing practices.

  • Turkey Meal – the ground clean combination of flesh and skin with or without accompanying bone, derived from the parts or whole carcasses of turkey or a combination thereof, exclusive of feathers, heads, feet and entrails.

  • Meat By-Products – 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 low-temperature fatty tissue and stomachs and intestines freed of their contents. It does not include hair, horns, teeth and hooves.

  • Poultry By-Product Meal – consists of the ground, rendered, clean parts of the carcass of slaughtered poultry, such as necks, feet, undeveloped eggs, intestines, exclusive of feathers, except in such amounts as might occur unavoidably in good processing practices.

When evaluating a pet food, we always prefer real, named meat and fish over more processed or generic sources.  Let’s look at the different types of protein sources in pet food.

140812 Dog with Meat L

Named Meat and Fish Proteins

Real named proteins, like beef, salmon, and chicken and not “meat”, “poultry”, or “fish”, are the least processed of all the proteins and the ones that we recommend are the first ingredient in your pet’s food.  Some of the more common named animal proteins include:

  • Chicken
  • Beef
  • Salmon
  • Lamb
  • Whitefish
  • Duck
  • Venison
  • Bison
  • Turkey
  • Pork


Meal is essentially product that has been ground up and has its water removed.  The result is a highly concentrated, albeit processed source of protein.  I liken “meal” to the condensed food that astronauts used to eat on space flights- a temporary solution to their nutrition problem when they had no access to whole foods.   In pet foods, meal can be used to increase the amount and percentage of protein in a food.  Although not necessarily ‘bad’, meals are more processed than the proteins themselves.  Further, there is some controversy around the use of Ethoxyquin as a preservative in some meals.  For these reasons, we prefer that meals are used in a supporting role (if at all), in the pet food formulations.

By products

By product is essentially the scraps that are left on the animal carcass after all of the meat is stripped away.  This is the lowest quality protein choice available because you don’t know what you are actually feeding your pet.  Further, the by product can be relatively un-digestible, so the protein that your pet really needs simply passes through their digestive system and ends up as waste.  Avoid foods with by products.

Unnamed Proteins

Unnamed proteins, like “meat”, “animal”, “poultry”, and “fish” are often used as meal, by product, or fat sources.  Does your pet food contain any of these?  If so, switch.  These designations are so vague you don’t know what the ingredient actually is.  Even worse—unnamed protein by product!  For example, “animal by product” or “animal by product meal”.

Non Meat Sources of Protein

Some foods use non-meat sources of protein such as corn, wheat, or pea protein.  As we showed in Dog and Cat Food Macronutrients: Protein Part 1:  with the digestibility and biological values, these are very difficult for pets to digest. Brands that use corn, corn meal, wheat and wheat gluten, etc. as main protein sources can technically meet industry standards for protein content but much of the protein passes right through the pet’s system unused.

Steve Pelletier
Steve Pelletier VP, Food

Steve is an advocate for healthy pet food offerings.

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