Tag Archives: AAFCO

By-Products in Dog Food: The Good and the Bad

For over a decade, by-products have gotten a bad rap in the pet food community. Some of this dislike of pet foods that contain by-products is backed behind the reasoning that foods that contain by-products often contain other unsavory ingredients as well. Many owners hate the idea of their beloved pet eating anything less than the best. Since by-products are by definition parts of the animal that people typically don’t eat, they are seen as inferior. But do by-products deserve this reputation? In this post, we will look at the definitions of various by-products, the pros, and the cons of these controversial ingredients.

For additional information on choosing a good commercial food, check out my post here that addresses more important things to keep in mind.

Definitions of ingredients:

Here are some of the definitions from the AAFCO’s website, which is the body responsible for establishing definitions for the ingredients used in pet foods. I am going to include some definitions other than just those for by-products, because I think the extra information is important for consumers to know.

So, first we will look at meat by-products:

  • Meat by-products is 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. It shall be suitable for use in animal feed. If it bears a name descriptive of its kind, it must correspond thereto.”
    To put it another way, it is most of the parts of the animal other than the muscle tissue, including the internal organs and bones. It includes some of the parts people eat (such as livers, kidneys and tripe), but also parts that are not typically consumed by humans in the US. Some by-products, like udders and lungs are not deemed “edible” by USDA for human consumption, but they can be perfectly safe and nutritious for animals not inclined to be swayed by the unappealing nature of these parts of animals. As with “meat,” unless the by-products are derived from cattle, pigs, sheep or goats, the species must be identified.”

So, meat by-products must come from slaughtered mammals, and the source must be named unless the by-products are from cattle, pigs, sheep, or goats. It must be suitable for animal feed; here, it is important to note that animal feed standards are not the same as the standards for what humans can eat. Animal feed standards are lower, which I will talk about briefly later in this post.

Next, we will see what poultry by-products means:

  • “Poultry By-Products must consist of non-rendered clean parts of carcasses of slaughtered poultry such as heads, feet, viscera, free from fecal content and foreign matter except in such trace amounts as might occur unavoidably in good factory practice. If the product bears a name descriptive of its kind, it must correspond thereto.”
    Similar to “meat by-products,” it is most of the parts of the bird that would not be part of a raw, dressed whole carcass. That may include the giblets (heart, gizzard and liver) but also other internal organs, heads and feet.

Poultry by-products must be from slaughtered animals as well, and contains all the parts that people typically don’t eat of chickens and turkeys and other poultry. It doesn’t contain muscle meat.

The note of meat by-products and poultry by-products being from slaughtered animals is important, because animals that died from other reasons can legally be used in pet foods. When meat comes from a slaughtered animal, that is more reassuring, as most of us wouldn’t feel comfortable feeding out dog an animal that died from unknown reasons.

Next, we will look at by-product meals and other meat meals. Meals are produced when the original animal parts used go through the process of rendering. During rendering, the “materials are subject to heat and pressure, removing most of the water and fat and leaving primarily protein and minerals. You will notice that the term “meal” is used in all cases; because, in addition to cooking, the products are ground to form uniform sized particles.” (https://www.aafco.org/Consumers/What-is-in-Pet-Food) So, this is a concentrated form of the ingredient listed basically. Some people prefer meals, as they typically mean the food has higher levels of animals protein. A drawback to meals is the fact that it means the food is even more highly processed then when fresh meat is used.

Taking a look at meat meal…

  • “Meat Meal is the rendered product from mammal tissues, exclusive of any added blood, hair, hoof, horn, hide trimmings, manure, stomach and rumen contents except in such amounts as may occur unavoidably in good processing practices. It shall not contain extraneous materials not provided for by this definition. …. {the definition goes on to include the required mineral specifications and required nutrient guarantees}….. If the product bears a name descriptive of its kind, composition or origin it must correspond thereto.”

    The rendering process is designed to destroy disease-causing bacteria, leaving an ingredient high in protein that while unappetizing to people appeals to the carnivore’s palate. Unlike “meat” and “meat by-products,” this ingredient may be from mammals other than cattle, pigs, sheep or goats without further description. However, a manufacturer may designate a species if appropriate (such as “beef meal” if only from cattle).”

The fact that this ingredient can contain animals other than cattle, pigs, sheep, or goats is something I really don’t like. I want to have an idea of what my dog is eating. Also, there is absolutely no specification that the animals used had to be slaughtered, so they could have died for any reason and be listed under this ingredient.

Similar to this, terms such as meat and bone meal and animal by-product meal are not specific enough for me, and the list of possible animals included by such terms is not available on the AAFCO’s website. For this reason, I don’t like these ingredients and I try not to give my dogs foods that use such ingredients.

Another common ingredient is poultry by-product meal:

  • “Poultry By-Product Meal consists of the ground, rendered clean parts of the carcasses of slaughtered poultry such as necks, feet, undeveloped eggs and intestines, exclusive of feathers except in such amounts as might occur unavoidably in good processing practices.….{the definition goes on to include the required mineral specifications and required nutrient guarantees}….. If the product bears a name descriptive of its kind, it must correspond thereto.”
    Essentially the same as “poultry by-products,” but in rendered form so most of the water and fat has been removed to make a concentrated protein/mineral ingredient.

This is, as the AAFCO surmises, basically a concentrated form of poultry by-products. I like that it must be sourced from slaughtered poultry, for the reasons listed above.

Benefits of By-Products:

In nature, dogs would not only eat the muscle meat of an animal; instead, they would eat the heads, brains, internal organs and the like. I think much dislike and distrust of by-products comes from people humanizing their dogs and not wanting them to eat anything that they themselves would not eat. I personally used to deem any by-products and completely unacceptable in pet food, but I have softened my stance since I learned of the many nutrients that can be found in organs that simply are not found in high quantities in muscle meat. Liver, for example, is rich in B-vitamins, vitamin A, and iron. Bones contain minerals such as phosphorus and calcium, and calcium is not found in muscle meat to any great level, although there is likely a difference in the digestibility of raw, fresh bone and bone that has been cooked to oblivion in pet food.

Negatives of By-Products:

By-products are basically everything but the muscle tissue, and muscle tissue is a good source of nutrition for dogs, so a food should preferably have both. Also, I have read many point out that while by-products specify that feathers and fur should not be included, unless unavoidable by good manufacturing processes, how could a manufacturer remove these parts on 1000s of animals being brought in to be use in pet food. This I feel is a good point, so I would just assume by-products have these parts. Personally, I don’t see issue with by-products as long as the source is named.

It is important to note that when an ingredient such as “chicken” is listed, it is not limited to muscle meat. Instead, it can refer to muscle meat, skin, and bones. So, it is important to keep in mind that even when “chicken” is on the label, it is probably not referring to muscle meat alone, which is what most people think when they hear “chicken.”

Animal Feed Standards vs. Human Food Standards:

An excellent article on this matter can be found on Susan Thixton’s website, Truth About Pet Food, which I will link here: (https://truthaboutpetfood.com/the-truth-pet-food-vs-human-food/#:~:text=Human%20Food%3A%20Nutrition%20facts%20are,%E2%80%9CServing%20size%20approximately%E2%80%A6%E2%80%9D)&text=’Protein’%20and%20’fat’,%25%20fat%20(or%20more). In short, human food must pass USDA inspection and must be approved to be “human edible.” Meat used in pet food does not require USDA inspection, and just because a pet food states that their ingredients come from USDA inspected facilities does not mean the meat is fit for human consumption. The meat could have been deemed unfit for human consumption, and that is why it ended up in the pet food. Country of origin information is not required to be made available to the buyer of pet food; this is required for human food. Human food ingredient information must be free to the public, whereas to obtain the complete list of definitions for pet food ingredients one would need to pay over $100 to the AAFCO to receive their “official” publication.

There are more differences, and I highly recommend her website for people who want to stay up-to-date on pet food information. I don’t agree with all of her conclusions about what and how animals should be fed, but there is a wealth of information available on her site and she has done an amazing amount of research into pet foods which is commendable.

Pet food is the end of line place that parts not fit for human consumption end up. This is economical, and it does put the parts to good use. Whether this is ethical is an argument for another post, and Susan Thixton talks extensively about it on her site. I feel the main issue is that people assume if there is not by-products, than the meat or poultry is the same quality as the meat and poultry they buy for themselves, but this is not the case and consumers should be aware of this.

Foods that Contain By-Products:

There are many, many foods that contain by-products. I only know of one that specifies that some of the by-products used are organ meats alone, and this is Bil-Jac’s dog kibble. Several of their kibbles have decent ingredients, with some of these ingredients being organ meats. But, this brand sadly utilizes BHA to preserve it’s kibble line, and this preservative is thought to have a estrogenic effect in the body. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4462476/). This isn’t a huge concern to me if the dog is only getting the occasional treat with this preservative, but I don’t feel comfortable feeding foods preserved with this day in and day out.

Most of the big name pet foods, such a Purina, Eukanuba, Iam’s, and Hills use by-products liberally in their foods. Iam’s and Eukanuba also seem to use decent amounts of meat in several of their formulas. Purina pro-plan also tends to use a combination of a named meat and by-products, as does Hills, but it seems to me that Iams and Eukanuba have more animal products on the ingredient label than either of the other brands.

I try to avoid these companies when I can for my dogs, because I prefer to support smaller companies, not large multi-national corporations. Thankfully, my dogs have always done better on brands like Fromm, Victor, and Wellness. But, I do have a cat who vomits any food other than one type of Fancy Feast canned food and Iam’s adult formula with chicken dry food. At the end of the day, you have to feed what your pet will eat and do well on.

So, my take aways…

  • Don’t think that just because a food does not have by-products means they are using only ingredients fit for human consumption. With the vast majority of pet foods, the ingredients are in the pet food because they didn’t make the cut for human food. If you only want human grade ingredients used, you need to either feed a food such as Honest Kitchen or Open Farm, or prepare your pet’s food at home.
  • I want to see a non-by-product, specific named meat listed before any by-products.
  • I personally in theory don’t have a problem with by-products being in the pet food, as long as the source is specifically named (such as beef by-products or chicken by-products).
  • In reality, since none of the brands I trust use by-products, I don’t typically feed foods to my dogs that contain by-products. But, if a brand I like, such as Wellness or Fromm produced a food with specifically named by-products, preferably organ meat being named in particular, I would happily purchase and feed the food to my dogs.
  • If I was going to feed one of the big name brands to my dogs, it would probably be one of Iam’s or Eukanuba’s lines, or possibly one of the Purina Pro-Plan Sport lines (most of the pro-plan products have too much corn-gluten for my liking). But, my dogs have always done better on smaller company’s foods or fresh diets.
  • I add liver and giblets to my dogs’ food when feeding commercial products, so they get the benefits of organ meats, or I mix in canned foods that have liver on the label. Organ meats are so nutrient dense, they should be a part of any diet as long as their is not a specific medical issue prohibiting their use.

Everyone has to feed their dog what they feel comfortable with and what the dog does well on. Stay informed and do what works!

Raina approves of the food in her toy