Caloric Feeding for Dogs
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The method discussed in this guide uses “biomath” to calculate the number of calories or kcals a dog particularly needs each day.
The information on this page contains excerpts taken from one of the modules/units in the Balanced Diet Formulation for Adult Dogs course
Dogs Eat to Meet Their Energy Needs
What is Energy? Energy is the capacity to do work.
A specific amount of energy is needed to maintain a given body weight, and even modest variances can bring about weight gain or weight loss in a dog. To determine the amount of food required, it is necessary to know the dog’s energy requirement and the energy content of the foods being fed.
Breed, age, activity, intact, fixed, growth stage, maintenance stage, pregnancy/lactation, and aging pet years; all of these are examples of factors used to determine your dog’s energy needs. Age and activity are important factors to consider when figuring out your dog’s energy requirements.
Energy Factors (EF)
The Energy Factor (EF) assigned to the math formula used to determine their maintenance energy requirements is based on the adult dog’s activity and/or age. Maintenance energy is the portion of total energy your dog’s body retains to maintain its normal lifestyle. This metabolizable energy is what is measured in kCals/Calories. There is more information about maintenance energy requirements further along in this guide.
Simplifying it for the Average Feeder
Sometimes when people start reading terms like “metabolizable energy requirements for dogs” or they get asked “how many kcals does your dog eat a day?” or they are presented in an online group with abbreviations like RER & MER; they get nervous and feel like they are about to get in over their head. DON’T BAIL, I’M GOING TO HELP YOU!
Let’s Get Into It from the Ground Up, Beginning with What a Calorie Is
Definition of a Calorie:
A: the amount of heat required at a pressure of one atmosphere to raise the temperature of one gram of water one degree Celsius that is equal to about 4.19 joules —abbreviation cal
— called also gram calorie, small calorie
B: the amount of heat required to raise the temperature of one kilogram of water one degree Celsius : 1000 gram calories or 3.968 Btu —abbreviation Cal
— called also large Calorie, Cal, Kilogram calorie, Kilocalories, & kCals. <—-This is what we use when feeding dogs. Calories and kCals are used interchangeably in casual conversation and they represent a unit of energy.
Now that you know what a Calorie/kCal is & that we use it for measuring a dog’s energy requirements; we need to talk about Basal Metabolic Rate (BMR) and Resting Energy Requirements (RER).
Basal Metabolic Rate (BMR)
The Basal Metabolic Rate (BMR) as I will call it from here forward; is defined as the energy required to maintain homeostasis in a dog in a post-absorptive state. <— This means the dog has been fasted or it’s laying down after a long period of not eating such as overnight; and is then awake in a thermoneutral environment that it is accustomed to.
Resting Energy Requirements (RER)
Resting Energy Requirements, that I am going to refer to as RER from now on, is the minimum energy your dog needs for its body to provide essential functions to live when it hasn’t been fasted. It is also referred to as Resting Fed Metabolic Rate (RFMR). This is the minimum amount of kCals needed to sustain life in a resting state who aren’t in a post-absorptive state.
The difference between BMR and RER is dietary-induced thermogenesis. What is that?? Dietary-induced thermogenesis or DIT is the increase in energy expenditure above basal fasting level, divided by the energy content of the food ingested.
REMEMBER WHEN I SAID DON’T BAIL, I’M GOING TO HELP YOU?
Here is the math for you to figure out your adult dog’s RER. I also have it built into a calculator for you to use, in case you don’t feel like doing math. You can access that calculator here.
The Formula for Determining Resting Energy Requirements for Adult Dogs (RER)
—-> RER = 70 x (body weight in kg)0.75<—-
This is the minimum amount of calories needed for your adult dog to function in a resting state.
Recap: RER is the minimum number of kCals your dog needs to function. Any type of activity increases that number. Increased activity from a resting state means the dog is burning more energy and therefore needs more kCals to maintain. Daily activity level, pregnancy, & lactation all increase an adult dog’s energy requirements from the RER to MER.
Maintenance Energy Requirements (MER)
Maintenance Energy Requirements that I am going to call MER here forward, are the kCals needed for a dog to maintain their ideal weight based on their current life stage & their activity level. MER requires more kCals than RER because the dog is doing more than life-sustaining functions. Other factors affecting MER are activity, pregnancy/lactation, climate, and health.
This is also sometimes referred to as Daily Energy Requirements (DER). MER and DER are different when discussing puppies but in common conversation when it pertains to adults, MER and DER are often used interchangeably.
Examples of Biomath for Determining Metabolizable Energy Requirements for Adult Dogs at Maintenance
MER = 95 x (body weight in kilograms) 0.75 (Less Active Adult Dogs)
MER = 110 x (body weight in kilograms) 0.75 (Typically Active Adult Pet Dogs)
MER = 130 x (body weight in kilograms)0.75 (Active Adult Dogs & Many Larger Breeds)
MER = 140 x (body weight in kilograms)0.75 (Young Adult & More Active Adult Dogs)
MER= 200 x (body weight in kilograms)0.75 (Great Dane)
The calculator includes the other Energy Factors (EF) that are most commonly applied to dogs.
There is more to formulating a balanced diet than just numbers on paper. The dog itself is a living organism and must be considered. The energy of the diet being fed, the bioavailability of nutrients in the foods, the nutrient density, and the digestibility of the food all factor into the proper creation/formulation of a balanced diet.
Puppies and pregnant, lactating adults, need to be fed a specific diet for that stage of their life. It’s best to reach out for a consult to ensure your puppy or pregnant or lactating female’s diet is correctly formulated.
Essential Nutrient Classifications & Which of Them Provide Energy
Water • Protein • Fats • Carbohydrates & Fiber • Vitamins • Minerals
Of the above nutrient classifications, only protein, fats, and carbohydrates provide energy to dogs. Water while vital to life, does not provide energy; nor do vitamins or minerals.
Water: Important Hydration Note
Water does not, in itself, provide energy to the body, but helps in metabolism which is essential for the body to derive energy, function and repair itself. The water to kcal intake ratio for a typical/healthy dog’s daily water need is estimated to be 1.0:1.0 mL water:kcal of metabolizable energy (ME).
Interspecies Comparisons of Micronutrient Requirements: Metabolic vs. Absolute Body Size by Rucker, R and Storms, D; (2002)
Vitamin Requirements Relationship to Basal Metabolic Needs and Functions by Rucker, R and Steinberg, F.M.; (2006)
National Research Council. Nutrient Requirements of Dogs and Cats. Washington, DC: National Academies Press; (2006)
Animal Nutrition, Seventh Edition, Determining Energy Requirements, Andrea J. Fascetti, et, al., Chapter 3, Determining Energy Requirements; (2012)
Balanced Diet Formulation for Adult Dogs, Module Three by Granillo, A; (2019)