There are many different ways that a company might test food to make sure that it meets nutrient adequacy. The first of which is simply testing the food to check that it meets AAFCO nutrient standards by laboratory analysis, another is by feeding the foods to staff dogs and monitoring their health. Both of these options are good ways to check nutrient adequacy, but not THE BEST ways to do so.
The gold standard would be to not only feed the diet to dogs in a controlled setting, monitoring the overall health of the dog while performing routine sample collection but to check the overall digestibility of the food.
This is where the AAFCO feeding trial and the digestibility trial comes in.
Today will are going to discuss what an AAFCO feeding trial is, the limitations of AAFCO feeding trials, the importance of AAFCO feeding trials, and why they matter. We will also be comparing AAFCO feeding trials to Digestibility trials, and look at the potential benefits of further digestibility testing for dogs. Finally, we will discuss why AAFCO and Digestibility trials are rare in the Dog Food Industry, and what we can do to advocate for more transparency and use of scientific testing in dog food.
Feeding Trials vs. AAFCO Feeding Trials
It is important to mention that there is a difference between a “feeding trial” and “AAFCO Feeding trial” – this is mainly due to the controls and variables concerning the diet itself.
Many companies will say their foods have undergone feeding trials, but when you go to look on the pet food bag to check, there are no AAFCO Feeding Trials listed. This is because their feeding trial was unofficial and did not meet the basic control standards of an AAFCO feeding trial.
Most of these non-AAFCO feeding trials are really just companies where their staff dogs have been eating the diets, then employees and staff members take their pup in for a physical exam, everything checks out, and they come back and say “everything was good” to the company. Some companies will keep paperwork of how long a dog has been on a diet and their bloodwork results. But overall, an unspecified feeding trial lacks structure and basic controls.
How do you know if a food has passed an AAFCO Feeding Trial?
Simple! Just check the packaging – every reputable dog food should have an AAFCO statement on the food staying if the food is complete and balanced, what life stage the food is for, and if the food has or is just “formulated to” AAFCO standards.
“Formulated To Statement” – aka no AFFCO Feeding Trial
“[DOG FOOD NAME] is formulated to meet the nutritional levels established by the AAFCO Dog (or cat) Food Nutrient Profiles for [LIFESTAGE].”
“Feeding Trial Statement” – aka food has undergone AAFCO Feeding Trials
“Animal feeding tests using AAFCO procedures substantiate that [DOG FOOD] provides complete and balanced nutrition for [LIFESTAGE].”
But what are the basic rules of an AAFCO Feeding Trial?
AAFCO Feeding Trial Protocol
The basic AAFCO Feeding Trial requirements are very simple… For maintenance diets (or diets intended for adults only and not puppies) the rules are as follows:
- Eight animals over a year of age must be included in the study.
- At the beginning of the study, all animals must be assessed by a veterinarian and be considered generally healthy and be at a healthy weight. A blood test must be done at the beginning of the study looking at least these values: hemoglobin, packed cell volume, alkaline phosphatase, albumin. And dogs MUST have normal values to be part of the study.
- Weight is monitored weekly within the study.
- Stools are monitored throughout the study for consistency.
- During the study, the animals must ONLY EAT the food tested.
- Study duration must be AT LEAST 6 months.
- At the end of the study, dogs are examined by a veterinarian again and bloodwork is repeated.
- TO PASS: 6 of 8 dogs must not have lost more than 15% of their body weight, stools should remain normal throughout the study, all blood work on those 6 dogs must be normal, and dogs should be considered generally healthy upon examination. It should also be noted that NO animals may die or be removed from the study due to nutritional related issues.
Now obviously you might look at these rules and think “this is not nearly enough” and as a veterinary professional – I agree with you. The AAFCO Feeding Trials rules are extremely basic, but from my conversations with facilities that regularly conduct research on pet foods – you should know some foods DO NOT pass AAFCO Feeding Trials, especially those containing exotic meats or ingredients.
These trials are designed to notice MAJOR nutritional imbalances and look at general safety. But the truth is if a company does not perform an AAFCO feeding trial it’s not that the food is bad or that it would cause issues – it’s just that we don’t know. And the more testing that is done to PROVE health, the more information we have as dog owners.
Common Misconceptions of AAFCO Feeding Trials
There are a lot of half-truths that companies and individuals will say regarding AAFCO Feeding Trials – many use these misconceptions as excuses as to why their company hasn’t performed trials, or why AAFCO trials are not necessary.
Laboratory Testing for AAFCO Feeding Trials is In-Humane
The first misconception of an AAFCO Feeding Trial is that it has to be done within a sterile laboratory environment. This is not true – large companies such as Hill’s, Purina and Royal Canin have GIANT nutrition facilities – these facilities look more like luxury dog daycare facilities than laboratories. Dogs have play-yards, socialization time with people, walks, facilities are kept clean, and many facilities actually allow tours and walk-throughs. So if you are ever curious as to the conditions, you can schedule an appointment to see for yourself.
Other companies like Just Food For Dogs have actually conducted at home feeding trials through a university – where dogs we actually kept within homes, with their families – while families followed strict protocols.
So though companies can choose to conduct feeding trials in sterile laboratory environments with dogs that do not get good socialization or exercise – they do not HAVE to do so. If you are concerned about the environment or conditions a feeding trial was performed – as the company for more information.
AAFCO Feeding Trials are Extremely Limited
Though the basic AAFCO feeding trial is limited in scope it does actually give us SOME information. According to board-certified veterinary nutritionists:
The important thing to remember is the companies are not required to ONLY do the basic trails, companies are more than welcome to do more extensive feeding trials. And many companies have performed trials for years or even for a lifetime on their diets. So though feeding trials can be limited in scope – they do not have to be. A company can choose to exceed the minimum AAFCO standards for a feeding trial.
Asking the company that manufactures your pet’s food for more details on their AAFCO feeding trials can give you a better idea as to not only how the trials were performed but how extensive their feeding trials are.
Some board-certified veterinary nutritionists have advocated for raising the bar for AAFCO feeding trials to include a full complete blood cell count, blood chemistry panel, urinalysis, essential fatty acid testing, serum inflammatory indices (– c-reactive protein, IL-6, and TNF-alpha (cats – serum amyloid A and IL-6), along with blood serum b-12 and vitamin e levels. Their recommendations include extending tests to a full year, with these parameters tested at 60, 180, and 360 days.
It is important to note that slight nutritional inadequacies may not appear in testing even after a year. So though AAFCO trials will catch potential major issues, they may not catch minor issues that would compound over time.
Digestibility Trials v. AAFCO Feeding Trails
Knowing that AAFCO Feeding Trials do have some limitations, one way to help avoid some of those problems is by also performing a Pet Food Digestibility Trial. What a digestibility trial does is looks at how a dog processes and digests a particular food. Where AAFCO Feeding Trials look at health parameters of the dog. A digestibility trial looks at the food itself and compares the food going in, with the product that comes out (aka the feces) to see how much of the food is digested by the animal, and how much is able to be utilized by the animal.
This gives different information to pet food manufacturers – it can allow manufacturers to adjust diet composition based on protein digestibility. For example, if a diet’s protein has 60% digestibility, they can either change protein types , cooking method OR increase the amounts of proteins to make sure they have adequacy within the diet.
Why do we need Digestibility Studies in Dog Food?
The main reason is that we don’t know what we don’t know. Back in 2016, researchers went to look at the digestibility of different types of meat meals – fish, chicken, and lamb in dogs (Tjernsbekk 2016). They formulated all the diets to AAFCO standards. However what they found what the lamb meal diet actually had poor overall protein digestibility. And one of the amino acids (proteins) within the diet, methionine was below recommended minimums. Though deficiencies of this amino acid were slight, if compounded over time without supplementing additional taurine nutrient deficiencies could cause heart problems, such as dilated cardiomyopathy.
The other reason why we need digestibility studies is that sometimes we don’t actually know the interactions that different ingredients will have with each other, and how those ingredients affect overall digestibility. For example, studies have shown that diets containing high amounts of soy (above 15%) actually start to inhibit the uptake of certain amino acids.(Mansilla 2019)
So our digestibility studies not only look at the individual ingredient digestibility but the interactions of the ingredients (including vitamins and minerals) with each other.
How do you know if a Digestibility Study has been done on a Dog Food?
This is the hardest part – you actually don’t. Many companies when asked directly will not share their digestibility study information claiming it is “proprietary”. However, other companies will send full digestibility laboratory analysis of their digestibility data when asked. If you are curious if your dog’s food has undergone a Digestibility study – contact the manufacturer and ASK. Some companies have actually started to publish this information publically in order to be more transparent with potential customers. This transparency is extremely helpful for pet parents trying to make the best decisions for their dogs.
Do we need Testing and Research on Dog Food?
There is still so much in the nutrition space that we still have to learn about dogs, and thus the need for proof is necessary especially with products that are new, or that are using ingredients/ingredient compositions that are new to the dog space. A majority of dog foods on the market – over 80% of foods – do not actually do AAFCO feeding trials on their diets. And a majority also do not perform digestibility trials either. So if you find a company that does both AAFCO feeding trials that are extensive and Digestibility trials – that is a positive indicator that the company is invested in proving to you (the consumer) that they have one of the best foods on the market.
But research is not actually the only thing to consider when choosing a dog food – asking the company about their quality control practices, who formulated their diets, their ingredient sourcing, along with evaluating the diet to see if it even appropriate for your pet is also extremely important.
How much importance do you place on things like AAFCO Feeding Trials and Digestibility Trials when you choose food for your dog? Does your dog’s current food go “above and beyond” to prove to your their nutritional adequacy?
Tjernsbekk MT, Tauson AH, Matthiesen CF, Ahlstrøm Ø. Protein and amino acid bioavailability of extruded dog food with protein meals of different quality using growing mink () as a model. J Anim Sci. 2016 Sep;94(9):3796-3804. doi: 10.2527/jas.2016-0526. PMID: 27898909.
Mansilla WD, Marinangeli CPF, Ekenstedt KJ, et al. Special topic: The association between pulse ingredients and canine dilated cardiomyopathy: addressing the knowledge gaps before establishing causation1. J Anim Sci. 2019;97(3):983-997. doi:10.1093/jas/sky488