When trying to select a food for your pet, you’ll often find it necessary to compare the nutritional information of two or three different formulas or recipes.
This way, you can select the food with the highest protein content, the lowest fat content, or other specifications based on your dog’s needs.
But unfortunately, this can be more complicated than many owners would expect at first glance. While dog food manufacturers are required to print some of the most important nutritional information on the package, dog food manufacturers often use different methods to obtain the nutritional values provided.
Below, we’ll talk about the way this information is conveyed, how to discover the truth about your dog food’s nutritional content.
We’ll also explain which method is best for dog owners to use and how to convert between the different types of information provided.
Dog Food Guaranteed Analysis (GA): The Easiest Info to Obtain
The Guaranteed Analysis (GA) provides basic nutritional information about a pet food – it’s the small box printed on the back or side of your dog’s food.
Where does the guaranteed part come in?
Minimally, the Guaranteed Analysis is required to list these amounts present in the dog food:
The GA must also include information about any other nutrients that are mentioned on the package.
For example, foods that are advertised as being high in calcium must disclose the calcium content in the Guaranteed Analysis. Similarly, foods that are labeled as being high in glucosamine or chondroitin, must list the amounts of these nutrients contained in the food.
Some manufacturers voluntarily include additional information, such as the ash or vitamin content of the food. Many foods that contain probiotics also list the number of colony-forming units included in the recipe.
Typical Analysis: Expensive, But More Reliable Testing
Some pet food manufacturers go further than providing a Guaranteed Analysis, by performing something called a Typical Analysis.
This often provides better information, as it involves multiple rounds of testing to account for the individual differences in samples. But, fewer manufacturers have their foods tested in this way as it is quite expensive.
The Typical Analysis is rarely printed on a pet food label; you’ll usually have to contact the manufacturer or visit their website to find this information.
How Is the Information in the Guaranteed Analysis Presented?
The information provided in the Guaranteed Analysis is typically listed as a percentage of the food’s mass.
So, a dog food with 20% protein contains 2 grams of protein for every 10 grams of food. This is called an “as fed” or “as is” basis.
However, these values can be provided in at least three other ways:
- Dry Matter Basis. Indicates the amount (in grams) of a nutrient relative to the dry weight of the food. This is similar to an “as fed” basis, except that all of the water is removed from the equation.
- Calorie Content Basis. Nutrient levels are provided relative to the caloric value of the food. In other words, a food may have 1 gram of protein for every 100 Calories.
- Percent Metabolizable Energy Basis. Indicates the percentage of a food’s calories that come from protein, fat, and carbohydrate content. For example, a food may derive 30% of its calories from proteins.
Dry Matter Basis: The Preferred Choice
In most cases, you’ll want to make food comparisons using a dry matter basis. In fact, while you should use a dry matter basis when comparing similar foods (such as when you are comparing two kibbles), it is the only accurate way to compare canned foods with kibbles.
We’ll explain why, but first, let’s take a step back and look at the things that make up your dog’s food.
What’s In Your Dog’s Food?
All dog foods are primarily comprised of proteins, fats, fiber, and carbohydrates, but they also contain one more basic ingredient: water.
Canned foods are full of water, and even kibbles contain some – a completely moisture-free food would likely be very difficult to chew and swallow, and it wouldn’t taste very good either.
But different foods contain different amounts of water, sometimes vastly so. And because water doesn’t provide any nutrients, it is important to account for the moisture content of a food when trying to make head-to-head comparisons.
So, you’ll generally want to use a dry matter basis when comparing one dog food to another. But unfortunately, few dog foods use a dry matter basis when preparing the Guaranteed Analysis – most list the information using an “as fed” basis.
Accordingly, you’ll need to do a little converting.
Convert the nutritional information on a dog food’s label from an “as fed” to a “dry matter” by doing the following:
- Determine how much dry matter is in the food by subtracting the amount of moisture indicated in the Guaranteed Analysis from 100 percent. In other words, if the Guaranteed Analysis lists a food’s moisture content as being 70%, then the dry matter content is 30%.
- Next, divide the content of the nutrient you are interested in (say, protein), by the dry matter percentage of the food. So, if the Guaranteed Analysis indicates that the food contains 10% crude protein, you can divide 10% by 30% (which we obtained in step 1). This means that this food has a dry matter protein level of 33%.
As you can see in this example, there is a 20% difference between the two figures. This could easily mislead owners or cause them to make the wrong choice.
How Is the Nutritional Information Obtained by Manufacturers?
Pet food manufacturers can determine the nutritional content of their food in a few different ways.
Some rely on nutritional content databases and then do the math to figure out how much of a given nutrient is in the food.
For example, the manufacturer will determine how much protein is provided by the chicken, peas and chicken meal in the recipe, and then add up the figures to obtain the total protein content.
Alternatively, pet food manufacturers can utilize a variety of laboratory testing techniques to determine the amount of each nutrient contained in the food. There are several different ways to do this, but proximate analysis is generally the most commonly used.
Proximate analysis uses chemical testing techniques to determine how much protein, fat, fiber, water, and ash is in a food. From this, the carbohydrate content can be inferred — after accounting for the protein, fat, fiber, water and ash, most everything left over is comprised of sugars or complex carbohydrates.
Crude Protein, Crude Fat, and Crude Fiber
One thing you’ll notice upon looking at the Guaranteed Analysis is that many dog foods refer to “crude protein,” “crude fiber,” or “crude fat” levels.
This doesn’t mean that the protein makes raunchy jokes – it refers to the technical method by which the information is obtained.
For example, to measure the crude protein content of a dog food, the food is analyzed using special tools to determine how much nitrogen is present.
Similarly, to measure the crude fat content of a food, the total amount of lipids (which are essentially the building blocks of fats) are measured.
Ultimately, these “crude” labels mean little to the average pet owner.
In a nutshell, while the GA is helpful for comparing similar kinds of dog food (dry vs dry for example) and is most readily available information, the dry matter analysis is much more helpful for getting a more thorough understanding of the composition of your dog’s food, especially when comparing dry to wet foods, and similarly different types of dog food.
How do you choose to evaluate dog food? What key factors do you look at when choosing food for your pooch? Tell us in the comments!