Although from a nutritional point of view canine adulthood is less critical than puppyhood and old age, feeding adult dogs a proper, well-balanced diet remains of paramount importance. This should not be surprising, as a correct diet is the cornerstone for ensuring optimal health and quality of life for our pets, as well as the most natural and effective way to increase their longevity. It is well known that errors in the diet of adult dogs can lead to a variety of nutrition-related problems that significantly impact their health and lifespan. These problems include digestive, renal, and metabolic disorders, as well as obesity (a true plague, especially for dogs living in industrialized countries) and its related consequences, such as orthopedic conditions, cardiovascular diseases, respiratory disorders, and type-2 diabetes.
Formulating a correct diet plan for an adult healthy dog requires first determining its daily calorie and nutrient needs. Nutritional requirement tables are available to determine the specific needs of any individual dog. However, these tables are perhaps more useful to veterinarians and pet nutritionists than to pet owners due to their complexity. Nevertheless, knowing the daily calorie requirements for adult dogs can help pet owners feed their pets the correct amount of commercial pet food. Those who prefer to feed adult dogs a homemade diet should consult a veterinarian or refer to a specialist book to avoid dietary errors and ensure their pets receive the proper amount of calories, as well as the correct proportion of all nutrients (proteins, carbohydrates, fats, vitamins, and minerals).
Calorie Requirements for Your Dog
One of the most important parameters used to determine calorie requirements and formulate the daily ration for adult dogs is metabolizable energy (ME), which refers to the calories from pet food that the dog’s body can use after digestion is complete. In other words, metabolizable energy equals the gross energy in pet food minus the energy lost in feces, urine, and combustible gases. The metabolizable energy requirement for an adult, healthy dog varies depending on several factors, the most important being its body surface area, which is related to the dog’s size.
It is worth noting that small dogs have a proportionally larger body surface area than large or giant dogs. This means that the calorie requirement per kilogram of body weight is higher for small breeds than for large and giant breeds.
Calculating the body surface area of a dog is not practical. For this reason, the evaluation of the metabolizable energy required by each individual dog (expressed in kilocalories per day) is based on a more practical parameter: metabolic weight (MW). This is defined as the body weight in kilograms (BW) raised to the power of 0.75: MW = BW^0.75. Using this formula, the calorie requirements of an adult healthy dog living in optimal climate conditions can be calculated as follows:
ME (kcal/day) = BW^0.75 * K
Here, K is a factor that accounts for the dog’s physical activity level: K = 132 for inactive dogs, 145 for moderately active dogs, 200 for intensely active dogs, and 300 for dogs engaging in strenuous, sustained physical activity (such as sled dogs). For example, an adult, inactive German Shepherd weighing 30 kg requires about 1,700 kcal of ME per day (ME = 30^0.75 * 132), while the same dog, in a condition of intense physical activity, needs about 2,550 kcal of ME per day (ME = 30^0.75 * 200).
Other factors also influence the daily calorie requirements of adult dogs, including their breed (some breeds are prone to obesity, while others are prone to being underweight), their physiological state (e.g., lactation, gestation), and the climate conditions (cold, mild, or hot). To calculate energy requirements in these specific conditions, correction factors are applied to the general formula for ME. For example, breeds prone to obesity, such as Beagles, Cockers, Labrador Retrievers, and Golden Retrievers, should have their energy requirement value multiplied by a correction factor of 0.9, meaning they need only 90% of the calorie amount calculated using the general ME formula. Conversely, breeds prone to being underweight, such as Greyhounds, Great Danes, and hunting breeds, have a correction factor of 1.1, meaning their daily energy requirement is 10% higher than the calculated value.
Once the daily energy requirement of an adult dog is known, determining the amount of commercial pet food it needs is simple. Divide the calculated daily calorie requirement by the calorie content listed on the pet food label. For example, if a dog requires 1,500 kcal per day and the pet food contains 500 kcal per can or pack, the dog will need 3 cans or packs per day (1,500/500). If the calorie content is not listed on the package, it can be calculated using the percentage content of protein, carbohydrates, and fat:
Calorie content (kcal/100 g of pet food) = (protein% * 3.5 + fat% * 8.5 + carbohydrate% * 3.5)
Of course, to properly feed an adult dog, the pet food should be of the highest quality, specifically formulated for adult dogs, and should contain the correct amount and proportion of nutrients. It is also important to remember that the total daily ration should be divided into two or preferably three feedings per day. This ensures the dog feels satiated throughout the day, helps avoid excessive fluctuations in blood sugar and insulin levels, and prevents stomach overload, which can lead to conditions like gastric torsion and dilation (a potentially fatal condition in predisposed breeds).
As mentioned earlier, feeding adult dogs a correct, well-balanced homemade diet is challenging. In this case, it is essential not only to know the specific daily energy requirements of the dog but also to be aware of all its other nutritional needs and the nutritional properties of any ingredients used in homemade food preparation. Moreover, once all this information is gathered, complex calculations are necessary to create a proper, well-balanced homemade diet. For these reasons, it is advisable to consult with a veterinarian or pet nutritionist before feeding an adult dog a homemade diet. They can provide customized recipes and specific diet plans tailored to the nutritional needs of each individual pet.
Finally, it is important to remember that, although dogs are considered part of the family, they are still animals and not humans. Therefore, we must respect their needs as animals first and feed them accordingly. This means avoiding a diet based on human foods or leftovers, as such a diet will inevitably lead to obesity and/or nutritional deficiencies and imbalances.