Basic nutritional requirements


The maintenance level of nutrition represents the minimum nutritional requirement of an adult dog with a “normal” activity level, living in an ambient temperature of around 20°C and without exceptional energy expenditure related to a specific physiological condition, such as gestation, lactation or growth. The maintenance nutritional requirement of a medium-sized dog (10-25 kg) serves as the benchmark. This is then adapted to the individual, based on size or breed, activity level, age, physiological condition and health.

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Maintenance energy requirement

The first step in the process is establishing the dog’s energy needs, which is what it needs to cover its vital functions and lead a reasonably active life. This is known as the maintenance energy requirement (MER).

This is based on the dog’s metabolic weight (W0.75, where W is the weight in kg) calculated as 130 kilocalories of metabolisable energy per kilogram of metabolic weight. The term metabolic weight is used for dogs to enable the comparison of animals whose weight can vary between 1 kg and 100 kg, depending on the breed but also on the individual. A dog’s energy requirement does not develop in tandem with its weight. The maintenance energy requirement of a 30-kg dog is not three times greater than a 10-kg dog’s, far from it. This energy must be provided through the food.


The first step in the process is establishing the dog’s energy needs, which is what it needs to cover its vital functions and lead a reasonably active life. This is known as the maintenance energy requirement (MER).


As stated above, MER is measured at a comfortable ambient temperature, so energy intake will always have to be adapted to the climatic conditions. A dog that lives outdoors in winter will have an MER that is double the normal value.

Good maintenance food: respecting the dietary balance

Once the energy requirement has been calculated, the various nutrients will be added to the formulation in such a way as to avoid any deficiency or excess, both of which could have adverse effects on the dog.

When feeding an adult dog in the maintenance stage of its life the main goals are:

- Keeping it at its healthy weight by using highly digestible ingredients and keeping the fat content at a sensible level;

© Diffomédia/Royal Canin
© Diffomédia/Royal Canin

Preserving the health and beauty of the skin and coat with the enriched provision of essential fatty acids, essential amino acids and B vitamins.

This food must be properly balanced in terms of nutrients. The following proportions serve as a starting point for a medium-sized adult dog:

- 25% protein

- 12% fat

- 5-7% dietary fibre

- 1.1% calcium

- 0.8-0.9% phosphorus.

Quantity is not the only factor, of course. The dog also needs to be able to digest the ingredients easily. Digestibility is strongly related to quality. The higher the quality, the more digestible the food will be.

The figures here are just average values and do not correspond to the needs of all dogs. Size, physiological condition and lifestyle are all variables in the equation, which will have to be fine-tuned to find the energy requirement and the nutritional requirement of an individual dog.

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The digestibility of a food, known as the coefficient of digestibility (CD), is an expression of how well the dog digests the food it eats, expressed as a percentage of the food eaten which is digested, absorbed and utilised by the body. While digestibility can be regarded as a fundamental criterion of a food’s nutritional quality by both the veterinary nutritionist and the owner, these two people will take two wholly different approaches.

For nutritionists, digestibility is a measure of what the dog retains in its body (digests) compared with what it consumes.

For owners, digestibility is a matter of the quantity, frequency and quality of defaecation.

Two parameters determine the overall appearance of dog faeces, reflecting the nutrition it takes in and its condition:

1) The digestibility of dry matter (DM) in a food, expressed as the coefficient of digestion (CD):

CD. DM = DM ingested - DM excreted/DM ingested

So, if a dog consumes 100g of dry matter (which is what is left of the food after the water is removed) and evacuates 20g of dry matter in its faeces, the digestibility of the food is 80%.

If the dog retains 85 g of the food rather than 80g, digestibility will be 85%, improved by five points, which represents a reduction in excreted dry matter from 20% to 15%, i.e. a reduction of 25%. A slight improvement in the digestibility of a food (5%) can therefore lead to a large reduction in the daily quantity of faeces (one quarter), which explains why serious manufacturers are conducting research in this field.

2) The water content of the faeces (65-75%) is also important. A drop in the water content will significantly reduce their volume and improve their consistency. The inclusion of different types of dietary fibre in the food will help achieve this.

Many parameters can affect the digestibility of a food, not least the dog itself. If a Beagle and a Fox Terrier are given the same food, the Fox Terrier’s digestibility will be about five points better than the Beagle’s. Likewise, the quantity of the food consumed also has an impact on digestibility. The greater the quantity at a single sitting, the lower the digestibility, which is why the splitting of the daily feeding amount into several sittings is often recommended for dogs with a sensitive gut or with a high nutritional requirement (sporting activity or suckling, for instance).

Digestibility is accordingly a highly significant factor for dogs, playing a major role in determining whether a food is good or bad.

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Basic nutritional requirements
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