Dry food and canned food: how to make comparison?

The average energetic density of a maintenance dry food is set between 3500 and 4200 kcal per kg. As a comparison, a canned food rarely brings more than 1000 kcal per kg, because of its high moisture content. To meet its energetic requirements, a dog must then eat 3-4 times more volume of canned food than dry food.

Example: a 15 kg dog requires around 1000 kcal per day. He will eat:

• 240 g of a dryfood that provides 4200 kcal/kg
• or 1 kg of a canned food that provides 1000 kcal/kg.

The evaluation of a nutritional intake, whatever it is, has to be related to the quantity of food ingested by the animal, then to the energetic density of the product. However, when one gets rid of the water content of the product, interesting information can be deducted from the comparison of the composition of the dry matter of the products.

Comparison between average moisture and dry matter contents in different types of food

Product category Moisture % Dry matter % Dry 8 - 12 (legally < 14) 88 - 92 Semi-moist 30 - 65 (legally >14 and < 60) 35 - 70 Fresh meats 50 - 75 25 - 50 Canned food 75 - 85 15 - 25

Let’s take the example of a dry food and a canned food:

Crude analysis Dryfood Canned food Moisture % 10,0 80,0 Proteins % 25,0 8,5 Fats % 12,0 4,0 Ash % 8,0 2,5 Crude cellulosis % 3,0 0,5

At first sight, nutritional guarantees seem systematically higher in dryfood than in canned food. But this comparison has no nutritional meaning. The crude analysis has to be related to the dry matter content. It can be done simply, thanks to a rule of three.

Canned food example:

80 % moisture means a dry matter content of: 100 - 80 = 20 %
8,5 % of proteins correspond to 20 % of dry matter
X % of proteins correspond to 100 % of dry matter
X = 8,5 x 100 X = 45,5 % 20

For all other nutriments, the analysis on dry matter is calculated the same way.

Analysis on dry matter Dry food Canned food Moisture % 0 0 Proteins % 27,8 42,5 Fats % 13,3 20,0 Ash % 8,9 12,5 Crude cellulosis % 3,3 2,5

Such a table shows clearly that canned food are generally largely richer in proteins and fats than dryfood. These values largely exceed the real requirements of dogs and cats.

Comparison of the analysis of different kinds of meats

Lean meat (ex: chicken) Fatty meat (ex:lamb) on crude on dry on crude on dry Moisture 70 0 50 0 Proteins 19,0 63,3 14,5 29,0 Fats 10,0 33,3 34,0 68 Ash 0,8 2,6 1,0 2,0

The most watery meats are lean meats: horse, beef, offals, rabbit… The least watery meats are fatty meats. Let’s notice that proteic and lipidic content can vary by twice as much.

Conclusion

When two products have very different moisture content, they can only be compared if their composition is related to dry matter. Contrary to a false idea, even the most proteic dry food (i.e: puppyfood or high energy food), still contain less proteins than canned food or fresh meat.

Donated by the Borg Cardona and Co. Ltd. visit Borg Cardona website