It's common knowledge that diet is central to the health and longevity of our pets, but selecting the right pet foods is not always an easy task.
Previously on the blog, we've looked at the importance of feeding a species-appropriate, nutritionally balanced diet free from dangerous chemicals and low-quality filler ingredients.
Some pet owners choose to feed home-prepared diets consisting of ingredients such as muscle and organ meats, raw eggs, and fresh fruits and vegetables. Home-prepared diets can be an excellent choice, but it's very important to make sure your pet's food meets their dietary requirements.
In fact, we recommend consulting with a veterinary nutritionist who can review your home-prepared diet to make sure it is nutritionally balanced and complete, and contains all the necessary vitamins and minerals your pet needs to stay healthy.
Because of the challenges involved with feeding home-prepared diets, many pet owners choose to feed commercial pet foods. The good news is that there are now many excellent commercial diets on the market. But unfortunately, there are also lots of commercial foods that can be very detrimental to your pet's health over the long term.
So, how can you choose a commercial diet that meets your pet's nutritional needs? The secret to selecting a high-quality diet is understanding the guaranteed analysis on pet food labels. In this post we'll help you understand the guaranteed analysis and how to use it to choose appropriate foods for your pet that will support their health and well being.
What Is the Guaranteed Analysis?
The guaranteed analysis (GA) on pet food labels is similar to the nutritional information printed on packages of human food. It is designed to help pet owners compare levels of at least four nutrients: protein, fat, fiber, and moisture.
If a product makes claims about other specific nutrients, they must also be included in the GA. The amounts of these nutrients are determined by chemical testing and computer formulation.
What Does 'Crude' Mean?
Pet food labels must guarantee minimum percentages of crude protein and fat, along with maximum percentages of crude fiber and moisture. The term 'crude' refers to the method of measuring the nutrient – not the quality of the ingredient listed.
Comparing Different Types of Pet Food
There are lots of different types of commercial pet foods available including wet and dry foods, freeze-dried, and raw. The GA on pet food labels can be used to compare these foods, but it's not as simple as it first may seem.
One of the main reasons for confusion when comparing different types of pet foods is that the percentages of nutrients in the GA fail to take moisture levels into account. In order to evaluate two different foods, it's necessary to compare them on a dry matter (DM) basis.
Calculating Dry Matter Basis
Here's how to calculate a GA ingredient on a dry matter basis:
- Subtract the moisture percentage on the label from 100% to get the total “dry matter” (DM)
- Divide the ingredient in question by the dry matter to get the actual ingredient content
- Multiply by 100 to give the total percentage of the ingredient on a dry matter basis
So, if you wanted to calculate the protein levels in a dry kibble dog food, here's how you would do it:
Let's say the dry dog food you are looking at has a GA of 10% moisture and 30% protein. First, you'd subtract the moisture percentage on the label from 100%:
100-10 = 90% dry matter
Next, you'd divide the percentage of protein by the percentage of dry matter:
30 ÷ 90 = 0.33
Finally, you'd multiply by 100 to arrive at the total percentage of protein on a dry matter basis:
0.33 x 100 = 33
After you've made this calculation you can see that the dry dog food has an actual protein content of 33%. Now let's take a look at calculating the percentage of protein in a wet canned dog food for comparison.
In the following example we'll find the total protein percentage on a dry matter basis for a canned dog food that has a GA of 78% moisture and 10% protein:
100-78 = 22% dry matter
10/22 = 0.45
0.45 x 100 = 45
In this example the food contains an actual protein percentage of 45%. As you can see, without calculating the protein percentage on a dry matter basis it would be easy to assume that the dry food contains far more protein than the wet food. But in this case, the wet food actually contains 12% more protein.
You can use this simple calculation to compare the fat or other nutrients when evaluating and comparing pet foods, too.
We hope this post helps you choose the best food for your pet's health. Questions or comments? Drop us a message in the comments section below and we'll get back to you!