Defining Energy Requirements For Your Pet

What is Energy?

Did you know that energy is not actually a nutrient? Rather, nutrients provide energy. And more specifically, those nutrients are proteins, carbohydrates, and fats. When it comes to pet food, energy is often measured and presented as kilocalories (kcal). To determine the amount of energy in pet food, we commonly use the “Atwater Factors”.

These are as follows:
     -> 1 gram of protein = 4 kcal of energy
     -> 1 gram of fat = 9 kcal of energy
     -> 1 gram of carbohydrates = 4 kcal of energy

From these values we can calculate the amount of energy in our pet food. In combination with your pet’s energy requirements, we can also determine the amount of food your pet should eat.

Energy Requirements for Dogs and Cats
Every species requires energy to function. And energy is needed at specific amounts for normal body function and maintenance. This is referred to as the basal, or resting energy requirement. When we consider other factors such as thermoregulation and moderate physical activity, we calculate the animal’s maintenance energy requirements (MER). This is then used to determine your pet’s individual daily requirements.

The calculation for MER uses your pet’s body weight to determine their energy needs. There is a different MER calculation for dogs and cats. Keep in mind that these equations may not be PURR-fect! The calculated MER is a great place to start but values may differ between individual animals. Therefore, adjustments may be necessary.

When Might You Need to Adjust?
For both cats and dogs, the energy requirements may differ between breeds. For example, even if your husky is the same weight as someone’s golden retriever the husky may require more energy for everyday functions! But the MER equation will provide you with the same MER value. There are many other reasons why the real MER for your pet may be different than those predicted. Again, the MER calculations are a great guide or starting spot. 

But there are multiple things to consider that result in individual differences. 

Check out these five ulti-MUTT factors to consider: 

  1. Activity Level - Some animals are super active. And some enjoy the simpler things in life, like a good nap! If your pet has a higher activity level, they will require more energy than those cozy couch potatoes.
  2.  Body Composition - When calculating MER we consider your pet’s body weight. Unfortunately, this does not account for how much of that weight is from fat, and how much is from muscle. Why is this important? Well, muscle takes more energy to maintain than fat! So, if your husky is, well…husky, then they may need less energy than the predicted value!
  3. Growing Animals (Kittens and Puppies) - There’s no KITTEN around when it comes to growth! Growing animals require much more energy than adults.
  4. Pregnancy - Unsurprisingly, growing another animal takes a lot of energy too! Pregnant cats and dogs will require much higher energy intakes. And this doesn’t stop once the litter is born. Providing their puppies and kittens with milk also uses up lots of your pet’s energy.
  5. Presence of Illness or Disease - In humans, when you are ill, your body uses energy to try to fight it off. The same is true for dogs and cats too. If your pet has an underlying condition, whether it be an injury or a disease such as cancer, they will need more energy than a healthy animal. Always consult your veterinarian if your pet has an illness or disease.

Signs that you may need to adjust your pet’s energy intake can include weight gain or weight loss and noticeable changes in energy level. If this occurs, consult with your veterinarian to determine an energy intake that is right for your pet!

Article written by 
Hannah Godfrey
BSc H | MSc Animal Nutrition
Tom&Sawyer Client Ambassador & Animal Nutritionist