“How much should I be feeding my dog or cat?”
Determining Energy Requirements for Dogs and Cats
Beth Hamper, DVM, PhD, DACVN
It is difficult for many owners to determine how much they should be feeding their pets. Feeding guidelines on pet food packages are based on averages and there is considerable variation in calorie (i.e. energy) requirements and metabolic rates between individual animals. Maintenance energy requirement is defined as the amount of energy required to maintain an animal in a state of energy balance, or the amount of energy needed to maintain the animal’s current weight. An accurate diet record or history in an animal at ideal body weight and condition is the best way to determine that animal’s maintenance requirement. But there can be several drawbacks when determining energy requirements from client records.1 First, many owners are not accurate when reporting total food intake (main meals and treats) for their dog/cat. Second, owners frequently use measures of volume, i.e. cups, to quantify foods rather than weight, i.e. grams, which are typically used in calculations. Third, owners do not use uniform measuring devices and a “cup” can be very different from owner to owner. And finally owners may not be very precise in measuring the volume of the food and under- or over-filling the measuring device will vary the actual amount fed.
Consequently, there have been several equations developed to determine energy requirements for pets, all of which use body weight as the primary component. In addition to weight, energy expenditure is also related to body surface area. Subsequent equations2 were developed that showed surface area is related to weight by the function kg0.67. This is the reason why smaller animals with a greater surface area to body weight ratio require a higher energy intake per unit of body weight compared to large animals. The mass exponent kg0.67 is still used today in some equations to normalize energy requirements in a wide range of body weights. Further work comparing basal energy expenditure with a wide range of body weights lead to the development of the equation used today for determining resting energy requirement.3
Resting Energy Requirement (RER) [kcal/day] = 70 X [body weight (BW) in kg0.75]
For dogs and cats, there have been two general approaches to calculating caloric or maintenance energy requirements. The first approach is to calculate the resting energy requirement using the above equation or the linear equation RER = 70 + (30 X BW in kg), and then multiplying it by a factor that takes into account activity level and/or physiological condition of the animal. For example the following factors have been determined for the dog and cat:
Dog: neutered adult = 1.6, intact adult = 1.8, Inactive/Obese prone = 1.4, Weight loss = 1.2,
Active = 2.0 – 8.0 (i.e. active sled racing dogs)
Cat: neutered adult = 1.2, intact adult = 1.4, Inactive/Obese prone = 1.0, Weight loss = 0.8,
Active = 1.6
The second approach has been to use a single equation that combines both resting and activity/neuter status together. The National Research Council (NRC)3 uses the following equations to predict maintenance energy needs for pet dogs:
Maintenance Energy Requirement (kcal/day) = 132 X BW kg0.75
In some cases it’s easier to use a linear equation. The following linear equation provided by the NRC gives results similar to the equation using kg0.75 for dogs weighing 8 to 20 kg.3
Maintenance Energy Requirement (kcal/day) = 358 + (39 X kg BW)
Equations using different multipliers are recommended for some dogs that been reported to have higher or lower energy requirements. The 2006 NRC3 has also recommended the following multipliers for the following specific groups of dogs: Young active dogs = 140 (i.e. 140 X BW kg0.75), Active Great Danes = 200, Active terriers = 180, Newfoundlands = 105, Inactive dogs = 95, Older active dogs = 105.
The equations for predicting energy requirements in cats are3:
Lean cats: Maintenance (kcal/day) = 100 kg BW0.67
Overweight cats: Maintenance (kcal/day) = 130 kg BW0.4
The cat linear equations are5:
Inactive cats: Maintenance (kcal/day) = 70 X kg BW
Active cats: Maintenance (kcal/day) = 80 X kg BW
It is important to advise owners that these equations are just a starting point in determining how much to feed an animal. As previously stated, there is considerable variation in energy requirements in pets as there is in people and true energy requirements can differ by as much as 50% from the predicted values. Therefore frequent weight monitoring is needed to determine if higher or lower caloric intakes are in order for each individual pet. If weight loss or weight gain is found, adjustments in caloric intake by 5-10% can then be made until ideal weight maintenance is achieved.
For Freshpet foods, caloric information is available on all packaging. It can also be viewed right here on the Nutritional Analysis pages located here.
1. Ramsey JJ, Chapter 3 Determining Energy Requirements in Fascetti AJ, & Delaney SJ. Applied veterinary clinical nutrition. (John Wiley & Sons, 2012).
2. Hill RC, & Scott KC. Timely topics in nutrition – Energy requirements and body surface area of cats and dogs. JAVMA-J. Am. Vet. Med. Assoc. 225, 689–694 (2004).
3. National Research Council Ad Hoc Committee on Dog Cat. Nutrient requirements of dogs and cats. (National Academies Press, 2006).
4. Gross KL, Zicker SC, et al. Chapter 5 Macronutrients in Hand MS, Thatcher CD, Remillard RL, Roudebush P, Novotny BJ. Small Animal Clinical Nutrition (Mark Morris Institute, 2010).
5. National Research Council Ad Hoc Committee on Dog Cat. Nutrient requirements of dogs and cats. (National Academies Press, 1986).