Moisture is the water content of a dog food, as expressed in a percentage. Dry kibble tends to have a moisture content of between 6 and 10 percent, semi-moist foods between 15 and 30 percent, and wet foods around 75 percent. As to be expected, there is a lot more water in a wet dog food than in a dry.
Does Moisture Matter?
The moisture content has a big effect on the percentages of other ingredients in a dog food, including the amounts of protein, carbohydrate, and fats. Pet caregivers often want to compare dog foods based on how much protein they contain. Comparing the basic data in the “guaranteed analysis” section of a label may not be the whole story.
The guaranteed analysis tells you how much of the total percent of the food comes from protein, fat, fiber, and moisture. If we remove the moisture element, the percentages of the other substrates, like fat and protein, will increase dramatically.
If moisture content were exactly the same for every dog food, we’d be comparing one food to another on the same ground. As it is, the difference in moisture content among foods is great. Which means, to get a more accurate picture of the nutritional value of a dog food, specifically the protein content, we should explore what would happen if we were to squeeze all the moisture out. What’s left over may surprise you.
The Dry Matter Basis
Knowing how to calculate the percentage of protein, minus the moisture content, will give you a much better picture of the real protein content of any dog food.
Even the FDA agrees. They say, “The weights of ingredients are determined as they are added in the formulation, including their inherent water content. This latter fact is important when evaluating relative quantity claims, especially when ingredients of different moisture contents are compared.” Consider seeing a package that has chicken as the number one ingredient which is about 60% moisture versus chicken meal which has less than 10% moisture. Which has more protein?
What a Pain!
Yes. Sometimes manufacturers really don’t make it easy on the consumer. Being committed and savvy is all part of being a great pet parent. By doing the calculations, you actually figure out what pet food companies are really adding. And the math isn’t too tricky.
The Math to Remove The Moisture Content
- First we’ll figure the dry matter in a wet dog food. Begin by assuming we’re starting at 100%. This 100% is the whole dog food, and everything in it.
100% (gee, this is easy!)
- Subtract the percentage of moisture, as it’s listed on the can. So if the can lists a 75% moisture content, you’re left with 25% dry matter.
100% (everything) - 75% (moisture) = the canned food in question is made up of 25% dry matter
- The next question we’re concerned with is: how much of that dry matter is actually protein? To figure this out, we’ll divide the amount of protein listed in the guaranteed analysis by the total amount of dry matter. Then we’ll multiply the whole thing by 100. Let’s say guaranteed analysis lists protein at 10%.
10 (protein) / 25 (dry matter) = 0.4
0.4 x 100 = 40%
- What we’ve learned is, this canned food has a protein content of 40 percent on a Dry Matter Basis.
- When you do the same calculations with a dry kibble of 10 percent moisture and 25 percent guaranteed analysis protein, you get a dry matter protein of only 28 percent.
Quite a difference, right? The wet food has nearly double the protein content. It could be worth combining the two to get your dog a bit more protein in his diet.
Choosing a Quality Food
A high quality dog food will have all the protein, as well as other key ingredients, that your dog needs to stay healthy. A good food for your pet will have a substantial dry matter protein content, typically above 20%.
However, remember that every dog may require different amounts of protein, calcium, and fat depending on their breed, age, activity levels, and other factors. Knowing a dog food’s moisture content will let you determine its major nutrient composition compared to other foods.
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This information is for informational purposes only and is not meant as a substitute for the professional advice of, or diagnosis or treatment by, your veterinarian. It has however been reviewed for accuracy by Dr. Joe, a board certified veterinary nutritionist and graduate of Cornell University's program for Veterinary Medicine.