As Fed to Dry Matter Conversions

What you're doing: Provide a hypothetical client with information on switching her cat's diet. Why you're doing it: Comparing pet food can be tricky without some background information. To compare the nutrient concentrations listed on the labels of two pet foods, be sure to compare “like to like”. Pet food labels provide nutrient information on an “as-fed” basis (i.e., as it is in the bag, can, or pouch). Comparing foods with the same moisture concentration is pretty straight forward, however, if you want to compare canned wet food to bagged dry food, you’ll need to do a dry matter conversion. What you need to know: All feeds contain some water, and the amount of water varies by feed type. The amount of water impacts a food’s nutrient content. To compare nutrients across feeds, you need to first express them on a “dry matter” basis. As-Fed – Food as it is in the bag, can, or pouch. On an as-fed basis, pet food may contain from as high as 88% water for canned foods down to 10% water for extruded foods. Dry matter – The part of the pet food which is not water. It is calculated by determining the percentage of water and subtracting the water content from 100%. Expressing nutrients on a dry-matter basis means expressing it as if there were no water in the food.