6 Criticisms of AAFCO Feeding Trials

In 2013, AAFCO, through its Feeding Protocols Expert Subcommittee (FPES) released a revised feeding protocol. In this blog, I have explained the meaning of AAFCO’s feeding trials, how they are conducted, benefits, drawbacks, and what you need to know.

Even though feeding trials are regarded the “gold standard” for pet food testing for nutrients adequacy, they have their shortcomings. I’ve listed six major concerns raised by veterinary experts that stood out in my research, such as animal cruelty, among other serious complaints. Read on to learn more.

This article is part of our general pet nutrition guides aimed at providing pet parents with the tools and resources needed to make informed decisions about their pet’s diet.

You may also want to check out these other guides;

Now, let’s get started.

What are AAFCO feeding trials?

The American Association of Feed Control Officials (AAFCO) is a non-profit organization that sets standards for the pet food industry but is not a regulator.

The American Feed Industry Association (AFAFCO) studies and discusses policies that affect the feed industry, as well as drafting model rules based on informed studies that feed control officials can take back to their states for customization and/or adoption.

Does AAFCO regulate?

AAFCO does not have the regulatory authority to enforce its policies. However, most states have adopted at least some of AAFCO’s model regulations and many pet food manufacturers choose to follow AAFCO’s guidelines even if they are not required to do so by law.

Who runs AAFCO?

Different AAFCO committees are tasked with specific sub-topics such as ingredient definitions, labeling, manufacture, inspection, and enforcement. These committees then bring their findings to the whole body for review and action. Most or all of AAFCO’s suggested rules for animal feed production and sale are enacted and/or codified by all of the individual American states.

But who are the committee members?

The committees are comprised of state feed control officials (the voting members) as well as representatives from the pet food industry, the Food and Drug Administration (FDA), the United States Department of Agriculture (USDA), and other interested groups.

Some organizations that have been credited in some AAFCO reports in the past include;

  1. Kansas State University
  2. American Feed Industry Association (
  3. American Pet Products Association (

Below are the 5 different AAFCO Committees appearing in some of the latest AAFCO Meeting minutes;

  1. Current Issues and Outreach Committee Report
  2. Education and Training Committee Report
  3. Feed and Feed Ingredient Manufacturing Committee Report
  4. Feed Labeling Committee Report
  5. Ingredient Definitions Committee Report

Below is a typical start of the Committee Report with the names of committee members for AAFCO’s 2019 Midyear Meeting in Savannah, Georgia;

A snapshot showing an Example of an AAFCO Feed labelling Committee report from AAFCO's website
A snapshot showing an Example of an AAFCO Feed Labeling Committee report from AAFCO’s website

You can see the entire AAFCO Committee Reports here.

AAFCO’s Power in the Pet Food Industry:

In order for pet food to be sold in the United States, it must meet the standards set by AAFCO and endorsed as meeting the ‘complete and balanced’ nutrition requirements by either:

  • Undergoing feeding trials and being approved by AAFCO or
  • Formulating the product to meet specific nutritional guidelines laid out by AAFCO.

Feeding trials are a type of research in which animals are fed a specific diet and monitored for health effects. Feeding trials are the most reliable way to assess the safety and efficacy of pet food.

AAFCO feeding trials have two components:

1. A nutrient adequacy trial

2. A palatability trial

The basis for the 2013 revisions was a comprehensive review of the current literature on pet nutrition as well as input from many stakeholders including pet food manufacturers, academia, feed control officials, and pet owners.

How are AAFCO feeding trials conducted?

The first step is to develop a diet that meets the animal’s nutritional needs. The diet must contain all of the essential nutrients required for the animal, including proteins, fats, carbohydrates, vitamins, and minerals.

Next, the diet is fed to a group of

animals over a period of time. The health of the animals is monitored throughout the trial to ensure that they are growing and developing normally.

At the end of the trial, the data is analyzed to determine if the diet meets AAFCO’s standards for complete and balanced nutrition.

Period of trials:

  • Puppies: 10 weeks
  • Kittens: 10 weeks
  • Adult dogs: 26 weeks
  • Adult cats: 26 weeks
  • Lactating dogs: 4 weeks
  • Lactating adult cats: 6 weeks

During the trial, the animals are fed the diet being evaluated as their sole source of nutrition. Their food intake and body weights are monitored throughout the

For puppies, the period of the trial is a minimum of 10 weeks

The adult dog trial is conducted over a period of 26 weeks, during which time the animals are fed the diet being evaluated and monitored for any adverse effects. At the end of the trial, the animals’ body weights, food consumption, and health status are evaluated.

30 adult dogs with 8 being control group are used in the trial. For both types of trials, a minimum of 8 animals per sex per species. The trial is designed to test for the following:

For lactating dogs, the period of the trials is a minimum of 4 weeks.The test should begin at or before estrus and continue until the pups are 4 weeks old, regardless of when they are weaned.

30 Puppies are required for a growth and reproduction trial evaluating food for all life stages. To evaluate a food intended for puppies, a minimum of 8 animals per sex is required.

4 weeks is the minimum duration for a nutritional adequacy trial evaluating food for lactating dogs.

The following diagram outlines the steps involved in

A minimum of 30 bitches is needed to calculate a historical colony average, and data taken from the same individual bitches shall be utilized. A minimum of eight bitches is required for the control group. All groups must have similar breed distributions.

Feeding parameters:

In the 2013 Brief that announced the changes to the feeding trial procedures, AAFCO stated that the test diet shall be the only source of nutrients with the exception of water. Dogs must be fed ad libitum or based on their energy requirements.

If there is an interruption to the feeding protocols must be disclosed and may invalidate the trials.

Data Captured During the Trials:

What are the data captured and the tracked during feeding trial?

The following data must be collected and tracked throughout the duration of the trial:

Blood parameters:


  • Hemoglobin is the protein in red blood cells that carries oxygen. It is used as a measure of anemia, which can be caused by iron deficiency or other problems.

Serum protein:

Serum protein is a measure of the proteins in the blood, including albumin and globulin. It is used as a marker of liver and kidney function, and can be decreased in cases of malnutrition.

Platelet count:

Platelets are cells that help with blood clotting. A low platelet count can indicate problems with the bone marrow or liver and can be seen in cases of malnutrition.


Tested to assess kidney and liver functions

Alkaline phosphatase:

– Abnormal levels can indicate Vitamin D deficiency.

Cell pack volume:

This test is to detect any possible disease

Total Plasma Protein: This test is to assess protein metabolism and detect any liver and kidney issues.

Globulin: TO detect any metabolic issues or allegies.

The snapshot below shows all the blood parameters that get tested with their reasons for testing them at the beginning during and at the end of the trials;

The snapshot showing all blood parameters that get tested during AAFCO's feeding trials
The snapshot showing all blood parameters that get tested during AAFCO’s feeding trials

Other blood parameters tested:

Though not required, the following can also be tested;

Urine Parameters tested:

Urine parameters such as pH level, specific gravity, glucose, bilirubin, ketones, among others are tested. The snapshot below has all the urine parameters.

Aside from the above parameters being tracked, the following are also monitored:

  • Clinical signs such as stool quality
  • Body weight
  • Adverse events such as vomiting or diarrhea
  • Food intake
  • Water intake

Additional guidelines to follow during the trials:

  • Body weights are measured at the beginning, weekly and at the end of the test.  
  • Hemoglobin, packed cell volume, and serum albumin shall be measured and recorded at the end of the test.
  • Puppies and kittens must be at least 8 weeks of age at the start of the test.
  • All animals must be in good health at the beginning of the test, with no evidence of disease. The trial must be conducted under conditions that meet AAFCO’s animal welfare guidelines. A veterinarian must be on staff throughout the duration of the trial.
  • The trial must continue for the entire period – for example, adult dogs and cats must complete the 6 months period required(26 weeks).

What Kind of Pet Food Pass the AAFCO trials?

To pass the AAFCO feeding trials, the results at the end of the trial should be as follows;

  1. At least 6 of the 8 dogs in the test group must not lose more than 15% of their body weight.
  2. Stools should remain normal throughout the study in at least 6 of the 8 test dogs in the test group.
  3. All blood work on at least 6 of the 8 dogs in the test group should be normal.
  4. Upon veterinary examination of the dog after the trial, it should be considered generally healthy.
  5. No animal should die during the trials due to diet-related issues.

While feeding trials have their disadvantages, they remain the most reliable method of assessing the nutritional adequacy of a pet food. If you are considering a new diet for your pet, it is important to ask your veterinarian if the diet has been tested using a feeding trial.

What is the alternative to feeding trials if they are expensive?

Formulating that meets AAFCO Food Nutrient Profile:

The American Association of Feed Control Officials (AAFCO) publishes minimum standards for the composition of pet food, as well as guidelines for conducting feeding trials. These standards are used by pet food manufacturers to formulate their products.

One way to assess the nutritional adequacy of a pet food is to compare its nutrient content to the AAFCO Food Nutrient Profile. This profile contains minimum standards for the nutrients that must be present in pet food, as well as recommended levels for certain nutrients.

Below is a table by Hills Pet showing key differences between “AAFCO’s Feeding Trial” and ‘Formulated‘ diets

A table by Hills Pet showing key differences between "AAFCO's Feeding Trial" and 'Formulated' diets
A table showing key differences between “AAFCO’s Feeding Trial” and ‘Formulated‘ diets

AAFCO’s Feed Inspector Manual:

During laboratory analysis of pet food being tested to determine if it meets AAFCO’s nutrient requirements, this 6th Edition of AAFCO’s Feed Inspector Manual lists all the information about the food formulation including

  • Lot/sample size
  • Type of products moving at the particular location – in case they’ll need to provide for contaminants
  • AAFCO sampling schedule used in the formulation
  • Products with a high violation rate
  • Products on enforcement list(s) (e.g. Stop Sale/Holding Order).
  • Follow-up of previous products in violation.
  • Coverage of classes of feed.
  • Info on the ability of the manufacturer’s laboratory to analyze the product or its ingredients.

To improve the accuracy of its tests, AAFCO has set a detailed protocol in which to test the samples. To illustrate this, they have even set the specifications on the tube to be used in obtaining and testing the samples.

Specs of Tube trier used in scooping the samples to test

They also provide guidance on proper technique to use when sampling bagged feed with a single slot tube trier as shown in the snapshot below that I obtained from AAFCO’s Feed Inspector Manual;

Why you shouldn’t rely on formulations without trials:

While the AAFCO Food Nutrient Profile can be used to assess the nutritional adequacy of pet food, it should not be used as the sole criterion when choosing a diet for your pet. Here are some key reasons why formulations are not as reliable as actual feeding trials;

  1. The profile does not take into account the palatability or digestibility of the ingredients used in the food
  2. It does not provide information on the possible adverse effects of feeding the diet.
  3. The nutrient levels in the food may not be adequate for all animals, depending on their individual needs.
  4. In addition, the AAFCO Food Nutrient Profile is only a minimum standard, and pet foods that meet or exceed these standards are not necessarily of higher quality than those that meet the minimum requirements.

When it comes to choosing a diet for your pet, it is important to consider all of the available information. This includes both the results of feeding trials and the AAFCO Food Nutrient Profile. If you have any questions about a particular pet food, please consult with your veterinarian.

AAFCO Statements for Feeding Trials and Laboratory Analysis

Lab Analysis statement:

If a laboratory analysis was used to verify that a pet food satisfies AAFCO’s nutritional profiles, the packaging will say so with this statement:

  • “(Name of food) is formulated to meet the nutritional levels established by the AAFCO (Dog/Cat) Food Nutrient Profiles for (life stage).”

AAFCO Feeding Trials Statement:

If a feeding trial was conducted and passed, the AAFCO statement on the pet food packaging should read:

  • “Animal feeding tests using AAFCO procedures substantiate that [DOG FOOD] provides complete and balanced nutrition for [LIFESTAGE].”

While there are some drawbacks to using the AAFCO Food Nutrient Profile as the sole criterion for choosing a pet food, it can be a helpful tool when used in conjunction with other information, such as feeding trials.

In fact, feeding trials have also been criticized by various scholars and experts:

Criticism of AAFCO Feeding Trials:

Animal cruelty:

One of the main criticisms of AAFCO feeding trials is that they involve animal cruelty. The animals used in these trials are typically kept in small cages and fed a diet that is not necessarily nutritious or palatable.

PETA ( launched a campaign claiming that the IAMs pet food brand had contracted an independent, contract laboratory to conduct trials on dogs and cats in cruel and unsanitary conditions. PETA had 26 video clips to prove their allegations and Proctor and Gamble, IAMs’ parent company severed ties with the lab.

Pet food producers put the optimum pet living environment in a lab setting that is not comparable to what pets are used to.

Only a few brands such as Just Food for Dogs and Answers Pet Food have managed to conduct at-home-feeding trials that are considered humane by animal activists. These two are now regarded as ‘cruetly-free pet food’

Below is a short video by Just Food for Dogs nutritionist explaining why their pet food trials were successful;

Time and cost:

Another criticism of AAFCO feeding trials is that they are expensive and time-consuming to conduct. This is due to the need for specialized equipment and trained personnel.

Inadequate sample size:

AAFCO feeding trials often have small sample sizes, which can lead to inaccurate results.

Trials Last for just 6 months:

Nancy of Whole Dog Journal argues that AAFCO trials are just 6 months and pet owners end up feeding their pets diets for several years on end. Her point is that there hasn’t been proven scientific studies to determine if pets can thrive on the diet for several years. She argues that 6 months is not a long enough period for the effects of any “nutritional excess, deficiency, or imbalance to express itself to the point of detectable health problems in the test dogs.” Calcium deficiency, for example, can take years to show up in bone problems and AAFCO is now aware of this concern. To detect calcium deficiencies earlier, serum alkaline phosphatase  (an enzyme found in liver and bone) is now being measured in addition to the standard blood tests done on all test dogs during AAFCO trials.

It fails to capture breed-specific nutrient requirements:

T.J. Dunn, DVM says that “the vast majority of data on which the AAFCO standards are based come from laboratory studies done on mixed-breed dogs”. He argues that these studies fail to take into account the fact that different breeds have different nutrient requirements.

Nancy uses the example of Bedlington Terriers which are an example of dog breed that requires a diet that is low in copper and high in zinc. There have been reports of dog foods passing AAFCO’s feeding trials and were later found to contain levels of taurine that proved too low to prevent the development of cardiomyopathy in consumers’ dogs.

No info on food digestibility:

One expert argued that “one of the most important factors in choosing a pet food – digestibility – is not addressed by the AAFCO feeding trials.” She says that food digestibility is “the number of nutrients absorbed and utilized by the body from a food”.

For example, two foods may have the same nutritional value but with significant variance in their digestibility levels. It is obvious that foods with a high digestibility are more efficient, meaning that less food needs to be fed to maintain the same body weight as a dog or cat eating a less digestible diet.

In other words, a food that is more digestible will result in fewer stools being produced and less nutrient loss. For this reason, some brands are also doing digestibility trials.

Digestibility trials measure how a dog digests and absorbs a particular meal. The AAFCO feeding trials focus on the health of the dog.

If a digestibility study reveals that the diet only has a 50% digestibility score, for example, the pet food manufacturer can change the protein in the diet to increase the digestibility score and increase the nutrients uptake by the pet.

A Study(Tjernsbekk 2016) that looked at proteins’ bioavailability and digestibility found that lamb diets had very poor digestibility. In our pet food reviews and especially when analyzing the ingredients, we now take note to explain why pet owners should avoid pet food with lamb as the only protein source.

Different nutrients can also have adverse effects when interacting and may affect bioavailability and digestibility. Another 2019 study by Kazuo Yamagata found that diets with high soy content(15%), inhibits the uptake of certain amino acid.

If you are unsure about a particular diet, please consult with your veterinarian.

Which pet food companies conduct AAFCO Feeding trials?

Feeding trials are very rare

The following pet food companies are among those that use feeding trials to demonstrate the nutritional adequacy of their products:

  1. Hillspet
  2. Purina
  3. Royal Canin

There is a reason only three brands conduct real Feeding trials as per AAFCO’s feeding protocols. It is super expensive. Only big companies such as Purina is able to dedicate a substantial budget running into the tens of millions to conduct feeding trials when it has other cheaper options.

Purina has invested heavily in R&D setting up a Genomics lab thoughts Purina Institute which costs millions of dollars.

Just this past November, Hills Pets was reported to have opened a $30 million Innovation Center for small dog nutrition. The 25,000-square-foot innovation center is in Topeka, Kansas.

Only these few pet food companies have the financial power needed to make such huge investments, in a full AAFCO Feeding trial.

Nikki, a registered veterinary nurse described the Nutritional Facilities of the big pet companies as “more like luxury dog daycare facilities than laboratories. Dogs have play-yards, socialization time with people walk, facilities are kept clean, and many facilities actually allow tours and walk-throughs.”

Feeding trials are time-consuming and expensive:

To date, feeding trials have been the most reliable method of demonstrating the nutritional adequacy of pet food. However, they are also the most expensive and time-consuming method. For this reason, many pet food manufacturers choose to use nutrient profiles instead.

How about at-home feeding trials?

A few brands have been reported to have successfully completed feeding trials at home instead of a controlled laboratory that requires millions of dollars to set up. Just Food For Dogs did this back in 2012 and its trials passed and they’ve posted their different completion paperwork on its website here.

 Just Food For Dogs

You are not getting an accurate picture of the nutrient profile

When choosing to use nutrient profiles instead, many pet food manufacturers are aware that they are not getting the same level of reliability. However, they feel that it is a more cost-effective option and that the potential risks are low. In some cases, pet food manufacturers will use a combination of both methods to demonstrate the nutritional adequacy of their products.

What does this mean to you as a pet owner?

When it comes to your pet’s food, you want to be sure that they are getting all the nutrients they need to stay healthy. One way to ensure this is to look for pet foods that have been through AAFCO feeding trials. These trials are conducted under strict protocols and overseen by an independent panel of experts.

There are two types of AAFCO feeding trials: nutritional adequacy trials and growth and reproduction trials. Nutritional adequacy trials are conducted to evaluate the nutrient content of the diet, while growth and reproduction trials are conducted to evaluate the effect of the diet on the health and development of puppies or kittens.


Q: Are AAFCO’s Feeding trials mandatory?

A: No, but many pet food manufacturers choose to use them as a way to demonstrate the nutritional adequacy of their products.

Q: Are feeding trials the only way to demonstrate the nutritional adequacy of a pet food?

A: No, nutrient profiles can also be used. However, feeding trials are generally considered to be the most reliable method.