NRC
NRC standards for “National Research Council.” NRC guidelines are based on the NRC 2006 publication.
When to Use: NRC is recommended for fresh diets, which generally includes all homemade diets.
Dog requirements are based on MW, or metabolic weight. MW is based on your dog’s current weight. This means that no matter how many calories you are feeding, your dog’s requirements will be the same.
Why Do We Use MW, not ME?
Many commercial foods, including those formulated to meet AAFCO guidelines, are formulated by ME, metabolizable energy. This means that the food contains a certain amount of nutrients per calorie of food. These foods come with a recommended feeding chart that labels how much food different weights of dogs should get, in order to receive the minimum level of nutrients (minerals, vitamins, amino acids). This works really well for commercial diets that are catering to a very wide audience, and very specific feeding guidelines cannot be given.
This means that for your dog to obtain the correct level of nutrients, you have to feed the recommended amount of food. Unfortunately, for many pet dogs, this ends up overfeeding calories, leading to weight gain. This is why the RFN Spreadsheet uses MW, which calculates your dog’s nutrient requirements based on weight. We believe this leads to a better formulated diet. However, special care should be given if your pet has higher energy needs – more information on that can be found in the RFN Full Course.
Cat requirements are based on ME, or Metabolizable energy. ME is based on your cat’s daily caloric goal. This means that as you change how many calories your cat should consume to maintain weight, your cat’s nutrient requirements will change.
Why Do We Use ME, not MW?
Nutrient requirements are based on predicted, or estimated, energy requirements of animals. For dogs, there is a huge variation in body weight and surface area for different breeds, so the estimated energy requirements can vary greatly. However, for cats, the variation in sizes, surface and thus, energy requirements are much, much lower. The NRC took this into consideration when setting nutrient requirements, so that differences in requirements for a cat of the same size, with differing energy needs, should cover the nutrients needed for that extra energy expended.
Weight Loss for Cats
If you are formulating a weight loss recipe for your cat, it’s very important to enter your cat’s daily caloric goal (in the pet profile) as the calories needed to maintain weight, not lose weight. However, when formulating, you should make sure that your recipe meets the weight loss goal for total calories.
FEDIAF
FEDIAF standards for “European Pet Food Industry Federation.” FEDIAF guidelines are based on the FEDIAF 2019 publication.
When to Use: FEDIAF is the guideline used for most UK commercial formulations. FEDIAF establishes recommendations based on research (including overlap with research used to define NRC requirements). When using FEDIAF for fresh diets, you should become familiar with the requirements and upper limits, as some of them are set with commercial formulations in mind, which may use less bio-available or supplement forms that have lower safe upper limits.
FEDIAF Dogs and Cats
Both requirements are based on a dry matter basis. This means that as you add more ingredients, and thus, more dry matter, to your recipe builder, the values will change continuously.
This may lead to some odd looking percentage bars when you are first starting your recipe! This is because when you have very little dry matter in the recipe (ie you just have a few, nutrient dense ingredients inputted), you may have a very high level of particular nutrients for a very small amount of dry matter. Shown below are two screenshots of the same recipe, after 1 ingredients vs after all 5 ingredients.
Even though the same amount of RMB is used (150g turkey neck), the Ca in the first screenshot shows that Ca is at 1185% of RA, while the second screenshot shows 259%. This is because we added more dry matter to the recipe, without adding more Ca.
Important Note!
FEDIAF requirements assume the diet has an energy density of 4000kcal/1kg DMB. Many fresh diets exceed this energy density, which means that the requirements are no longer accurate for that diet. Please keep this in mind when formulating with FEDIAF.
Future Changes
V4 of the RFN Spreadsheet will switch to using FEDIAF values by ME, on a recipe caloric basis.
AAFCO
AAFCO standards for “Association of American Feed Control Officials.” AAFCO guidelines are based on the AAFCO 2019 publication.
When to Use: AAFCO is the guideline used for most US commercial formulations. They are based on the NRC requirements, and adjusted to suit commercial diets, such as accounting for lower bio-availability ingredients, extrusion, and commercial supplementation forms. We do not recommend using it for fresh diets.
AAFCO Dogs and Cats
Both requirements are based on a dry matter basis. This means that as you add more ingredients, and thus, more dry matter, to your recipe builder, the values will change continuously.
This may lead to some odd looking percentage bars when you are first starting your recipe! This is because when you have very little dry matter in the recipe (ie you just have a few, nutrient dense ingredients inputted), you may have a very high level of particular nutrients for a very small amount of dry matter. Shown below are two screenshots of the same recipe, after 1 ingredients vs after all 5 ingredients.
Even though the same amount of RMB is used (150g turkey neck), the Ca in the first screenshot shows that Ca is at 1185% of RA, while the second screenshot shows 259%. This is because we added more dry matter to the recipe, without adding more Ca.
Important Note!
AAFCO requirements assume the diet has an energy density of 4000kcal/1kg DMB. Many fresh diets exceed this energy density, which means that the requirements are no longer accurate for that diet. Please keep this in mind when formulating with AAFCO.
Future Changes
V4 of the RFN Spreadsheet will switch to using AAFCO values by ME, on a recipe caloric basis.