Deciphering and comparing the multitude of dry and wet pet foods available can give you a headache.  While there are certain requirements and regulations that pet food companies must follow, the labels are often not very helpful and/or misleading.  I get the question of “what food should I feed my pet” every day, but the answer is not a simple and clear cut one.  Each pet may respond to different formulations, ingredients and nutrient profiles differently.  To make matters more confusing, underlying diseases, necessity of weight loss/weight gain, and activity level all need to be taken into account when deciding on the most appropriate diet to feed your pets.  The most important thing I tell my clients is to not determine the quality of food by the look of the bag, or falling for the marketing schemes.  The labels may state “low-fat”, “grain-free”, “natural”, or “holistic”.

To start with, pets need a quality protein source.  Cats are obligate carnivore, meaning they need to obtain all of their necessary amino acids from their diet.  Dogs are not obligate carnivores, but naturally need protein since they are natural scavengers (can be animal or plant protein).  When looking at the ingredients of the pet food, realize that they are listed in order of prevalence.  Try to find a food with quality protein (unless otherwise advised to not due to certain conditions) and one or two protein sources within the first few ingredients.  If a cat food has taurine in the ingredient list, be aware that this food may not contain quality sources of skeletal muscle protein which is where this amino acid comes from.  This amino acid is required for cats since they cannot produce it, and it is necessary in order to prevent certain heart diseases.

Dogs and cats need good sources of fats and oils for every day function of enzymes, metabolic processes, and healthy coat/skin.  Some diseases make it necessary for pets to eat lower fat diets (pancreatitis, obesity, etc). They also need some carbohydrate sources, but again with certain ailments, these may need to be controlled at lower levels.  Your veterinarian should be able to advise you of your pets’ needs.

AAFCO (Association of American Feed Control Officials) requires the following to be included for pet food labels:

• Brand of product name
• Species the product is intended for
• Quantity statement
• Guaranteed analysis
• Ingredient list including drugs and food additives
• Nutritional adequacy statement
• Feeding directions
• Validation for any product claims or comparisons
• Manufacturer or distributor information

AAFCO also has requirements for the guaranteed analysis, including:

• Crude protein as a minimal percentage
• Crude fat as a minimum percentage
• Crude fiber as a maximum percentage
• Moisture as a maximum percentage

The carbohydrate content can be calculated by subtracting these percentages, including the ash content, from 100%.  The guaranteed analysis is in percentage as fed, which means the food contains water when it is analyzed.  In order to compare different diets, you should convert to dry matter basis, which takes water out of the equation. Without doing this, comparing two different diets would be like comparing apples to bananas.  Converting from as fed to dry matter is simple.  First, calculate the percent dry matter by taking 100% – percent moisture.  Then divide the percent as fed by the percent dry matter.  Finally take this number and multiple by 100%.  No you can compare different diet formulations, even dry versus wet.

Example: canned food with 6% minimum crude protein in 74% maximum moisture. The food is 26% dry matter. Divide 6 by 26 = 0.23, multiple by 100% = 23%

To make labels even more confusing, there are many ways to express the nutrient composition of each pet food.  The most common ways are: as fed percentage, dry matter percentage, calorie content basis and percent metabolizable energy.

There are two ways to ensure nutritional adequacy as required by AAFCO.  These include animal feeding test and formulating the diet to meet and/or exceed AAFCO minimum requirements.  If the diet doesn’t meet the minimum nutrient profile for an animal or lifestage, then the nutritional adequacy statement will state the food is intended for supplemental feeding or intermittent use only.  This nutritional adequacy statement is a label requirement, and it will indicate what species and lifestage the diet was intended for as well as how it was confirmed as adequate.  If a label has “all life stages”, this is formulated for kitten/puppy, which usually has higher calories, calcium and phosphorus. You may also see “adult maintenance” or “senior”, for example.  These statements can help guide you to what is most appropriate for your pet.  Diets may also claim size specific formulas, which can be quite important especially for large breed puppies to help with appropriate bone growth.  Other formulas may have breed specific claims.

To make labels even more confusing, there are many ways to express the nutrient composition of each pet food.  The most common ways are: as fed percentage, dry matter percentage, calorie content basis and percent metabolizable energy.

When evaluating different diets and formulations, it is important to take all of this into account, as well as your pet’s age, body condition, and overall health. When in doubt, be sure to consult your veterinarian.  Hopefully this gave you a little incite on how to read labels and identifying the most appropriate diet for your pet’s needs.

Dr Stephanie Lemus

Resources:

http://www.petmd.com/cat/nutrition/evr_multi_deconstructing_pet_food_labels?page=show#

http://petfood.aafco.org/