{ Many thanks to Ellie May (Crystal) for taking the time to write this for the Library
. }
When feeding a wet food (canned, homemade, semi-moist, or raw), it needs to be converted to a
dry matter basis to get an accurate percentage of protein, fat, and fiber content. By "converting", you are mathematically removing the moisture (not considered a nutrient) and will be left with the dry matter only. This can also be done with kibble; however, the amounts of nutrients are very similar before and after conversion. Also remember that the guaranteed analysis states minimums and maximums. The percentages given are usually
not exact.
To convert to a dry matter basis, divide the nutrient by the reciprocal of the moisture. Example 1:
Guaranteed Analysis of ABC Dog Food
Protein 11% (minimum)
Fat 9% (minimum)
Fiber 3% (minimum)
Moisture 77% (maximum)
The reciprocal of the moisture is 23 (100-77).
To find the protein content, divide 11 by 23 to get 0.47826. Move the decimal point two places to the right or multiply by 100 to get 47.826. Round off to 48 to get 48% protein (minimum).
To find the fat content, divide 9 by 23 to get 0. 39130. Move the decimal point two places to the right or mulitiply by 100 to get 39.130. Round off the 39 to get 39% fat (minimum).
To find the fiber content, divide 3 by 23 to get 0.13043. Move the decimal point two places to the right or multiply by 100 to get 13.043. Round off to 13 to get 13% fiber (minimum).
Example 2:
Guaranteed Analysis of XYZ Dog Food
Protein 12% (minimum)
Fat 8% (minimum)
Fiber 2% (minimum)
Moisture 78% (maximum)
The reciprocal of the moisture is 22 (100-78).
To find the protein content, divide 12 by 22 to get 0.54545. Move the decimal point two places to the right or multiply by 100 to get 54.545. Round off to 55 to get 55% protein (minimum).
To find the fat content, divide 8 by 22 to get 0.36363. Move the decimal point two places to the right or multiply by 100 to get 36.363. Round off to 36 to get 36% fat (minimum).
To find the fiber content, divide 2 by 22 to get 0.09090. Move he decimal point two places to the right or multiply by 100 to get 9.0909. Round off to 9 to get 9% fiber (minimum).